LTC6240, 41, 42 Datasheet by Analog Devices Inc.

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l ’ LINE I \p LTCé240‘LTC6241zLTC6242 TECHNOLOGY ,_ L7 LJUW
LTC6240/LTC6241/LTC6242
1
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Single/Dual/Quad 18MHz,
Low Noise, Rail-to-Rail Output,
CMOS Op Amps
The LTC
®
6240/6241/LTC6242 are single, dual and quad
low noise, low offset, rail-to-rail output, unity gain stable
CMOS op amps that feature 1pA of input bias current. Input
bias current is guaranteed to be 1pA max on the single
LTC6240. The 0.1Hz to 10Hz noise of only 550nVP-P, along
with an offset of just 125µV are signifi cant improvements
over traditional CMOS op amps. Additionally, noise is
guaranteed to be less than 10nV/√Hz at 1kHz. An 18MHz
gain bandwidth, and 10V/µs slew rate, along with the wide
supply range and low input capacitance, make them perfect
for use as fast signal processing amplifi ers.
These op amps have an output stage that swings within
30mV of either supply rail to maximize the signal dynamic
range in low supply applications. The input common mode
range extends to the negative supply. They are fully speci-
ed on 3V and 5V, and an HV version guarantees operation
on supplies up to ±5V.
The LTC6240 is available in the 8-pin SO and the 5-pin SOT-
23 packages. The LTC6241 is available in the 8-pin SO, and
for compact designs it is packaged in a tiny dual fi ne pitch
leadless (DFN) package. The LTC6242 is available in the
16-pin SSOP as well as the 5mm × 3mm DFN package.
n Photo Diode Amplifi ers
n Charge Coupled Amplifi ers
n Low Noise Signal Processing
n Medical Instrumentation
n High Impedance Transducer Amplifi er
n 0.1Hz to 10Hz Noise: 550nVP-P
n Input Bias Current:
0.2pA (Typ at 25°C)
1pA Max (LTC6240)
n Low Offset Voltage: 125μV Max
n Low Offset Drift: 2.5µV/°C Max
n Gain Bandwidth Product: 18MHz
n Output Swings Rail-to-Rail
n Supply Operation:
2.8V to 6V LTC6240/LTC6241/LTC6242
2.8V to ±5.5V LTC6240HV/LTC6241HV/LTC6242HV
n Low Input Capacitance
n H-Grade Temperature Range: –40°C to 125°C
n Single LTC6240 in 5-Pin Low Profi le (1mm)
ThinSOT™ Package and 8-Pin SO for PCB Guard Ring
n Dual LTC6241 in 8-Pin SO and Tiny DFN Packages
n Quad LTC6242 in 16-Pin SSOP and 5mm × 3mm
DFN Packages
Low Noise Single-Ended Input to Differential Output Amplifi er Noise Voltage vs Frequency
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
DESCRIPTION
FEATURES
APPLICATIONS
+
R2
200k
C1
10pF
C2
10pF
+2.5V
–2.5V
6241 TA01a
R4
4.99k
R1
200k
VIN
VOUT+
VOUT
1/2
LTC6241
+
1/2
LTC6241
C3
10pF
R3
4.99k
C4
10pF
FREQUENCY (Hz)
20
10
NOISE VOLTAGE (nV/√Hz)
30
40
50
60
1 100 1k 100k
6241 TA01b
010 10k
TA = 25°C
VS = ±2.5V
VCM = 0V
LTC6240/LTC6241 / LTC6242 j j j j j j j j 1%; w E E E E E E E E :I :I 3555 I: I: L7LJCUEN2
LTC6240/LTC6241/LTC6242
2
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Total Supply Voltage (V+ to V)
LTC6240/LTC6241/LTC6242 ...................................7V
LTC6240HV/LTC6241HV/LTC6242HV ....................12V
Input Voltage .......................... (V+ + 0.3V) to (V – 0.3V)
Input Current ........................................................±10mA
Output Short-Circuit Duration (Note 2) ............ Indefi nite
Operating Temperature Range
LTC6240C/LTC6241C/LTC6242C ..........40°C to 85°C
LTC6240I/LTC6241I/LTC6242I .............40°C to 85°C
LTC6240H/LTC6241H/LTC6242H ....... 40°C to 125°C
(Note 1)
Specifi ed Temperature Range (Note 3)
LTC6240C/LTC6241C/LTC6242C .............. 0°C to 70°C
LTC6240I/LTC6241I/LTC6242I .............40°C to 85°C
LTC6240H/LTC6241H/LTC6242H ....... 40°C to 125°C
Junction Temperature ........................................... 150°C
DHC, DD Package ............................................. 125°C
Storage Temperature Range ..................65°C to 150°C
DHC, DD Package .............................. 65°C to 125°C
Lead Temperature (Soldering, 10 sec)...................300°C
ABSOLUTE MAXIMUM RATINGS
LTC6240 LTC6240
OUT 1
V 2
TOP VIEW
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
+IN 3
5 V+
4 –IN
+
TJMAX = 150°C, θJA = 250°C/W
1
2
3
4
8
7
6
5
TOP VIEW
NC
V+
OUT
NC
NC
–IN
+IN
V
S8 PACKAGE
8-LEAD PLASTIC SO
+
TJMAX = 150°C, θJA = 190°C/W
LTC6241 LTC6241
TOP VIEW
DD PACKAGE
8-LEAD (3mm s 3mm) PLASTIC DFN
5
6
7
8
4
3
2
1OUT A
–IN A
+IN A
V
V+
OUT B
–IN B
+IN B
B
A
TJMAX = 125°C, θJA = 43°C/W
UNDERSIDE METAL CONNECTED TO V
(PCB CONNECTION OPTIONAL)
1
2
3
4
8
7
6
5
TOP VIEW
V+
OUT B
–IN B
+IN B
OUT A
–IN A
+IN A
V
S8 PACKAGE
8-LEAD PLASTIC SO
B
A
TJMAX = 150°C, θJA = 190°C/W
LTC6242 LTC6242
16
15
14
13
12
11
10
9
17
1
2
3
4
5
6
7
8
OUT D
–IN D
+IN D
V
+IN C
–IN C
OUT C
NC
OUT A
–IN A
+IN A
V+
+IN B
–IN B
OUT B
NC
TOP VIEW
DHC PACKAGE
16-LEAD (5mm s 3mm) PLASTIC DFN
B
A
C
D
TJMAX = 125°C, θJA = 43°C/W
UNDERSIDE METAL CONNECTED TO V (PCB CONNECTION OPTIONAL)
GN PACKAGE
16-LEAD PLASTIC SSOP
1
2
3
4
5
6
7
8
TOP VIEW
16
15
14
13
12
11
10
9
OUT A
–IN A
+IN A
V+
+IN B
–IN B
OUT B
NC
OUT D
–IN D
+IN D
V
+IN C
–IN C
OUT C
NC
B
A
C
D
TJMAX = 150°C, θJA = 135°C/W
PIN CONFIGURATION
LTC6240/ LTC6241 /LTC6242 L7 LJUW
LTC6240/LTC6241/LTC6242
3
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LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE
LTC6240CS5#PBF LTC6240CS5#TRPBF LTCRR 5-Lead Plastic TSOT-23 0°C to 70°C
LTC6240HVCS5#PBF LTC6240HVCS5#TRPBF LTCRS 5-Lead Plastic TSOT-23 0°C to 70°C
LTC6240IS5#PBF LTC6240IS5#TRPBF LTCRR 5-Lead Plastic TSOT-23 –40°C to 85°C
LTC6240HVIS5#PBF LTC6240HVIS5 #TRPBF LTCRS 5-Lead Plastic TSOT-23 –40°C to 85°C
LTC6240HS5#PBF LTC6240HS5#TRPBF LTCRR 5-Lead Plastic TSOT-23 –40°C to 125°C
LTC6240HVHS5#PBF LTC6240HVHS5#TRPBF LTCRS 5-Lead Plastic TSOT-23 –40°C to 125°C
LTC6240CS8#PBF LTC6240CS8#TRPBF 6240 8-Lead Plastic SO 0°C to 70°C
LTC6240HVCS8#PBF LTC6240HVCS8#TRPBF 6240HV 8-Lead Plastic SO 0°C to 70°C
LTC6240IS8#PBF LTC6240IS8#TRPBF 6240I 8-Lead Plastic SO –40°C to 85°C
LTC6240HVIS8#PBF LTC6240HVIS8#TRPBF 240HVI 8-Lead Plastic SO –40°C to 85°C
LTC6240HS8#PBF LTC6240HS8#TRPBF 6240H 8-Lead Plastic SO –40°C to 125°C
LTC6240HVHS8#PBF LTC6240HVHS8#TRPBF 240HVH 8-Lead Plastic SO –40°C to 125°C
LTC6241CDD#PBF LTC6241CDD#TRPBF LBPD 8-Lead (3mm × 3mm) Plastic DFN 0°C to 70°C
LTC6241HVCDD#PBF LTC6241HVCDD#TRPBF LBRR 8-Lead (3mm × 3mm) Plastic DFN 0°C to 70°C
LTC6241IDD#PBF LTC6241IDD#TRPBF LBPD 8-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C
LTC6241HVIDD#PBF LTC6241HVIDD#TRPBF LBRR 8-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C
LTC6241CS8#PBF LTC6241CS8#TRPBF 6241 8-Lead Plastic SO 0°C to 70°C
LTC6241HVCS8#PBF LTC6241HVCS8#TRPBF 6241HV 8-Lead Plastic SO 0°C to 70°C
LTC6241IS8#PBF LTC6241IS8#TRPBF 6241I 8-Lead Plastic SO –40°C to 85°C
LTC6241HVIS8#PBF LTC6241HVIS8#TRPBF 241HVI 8-Lead Plastic SO –40°C to 85°C
LTC6241HS8#PBF LTC6241HS8#TRPBF 6241H 8-Lead Plastic SO –40°C to 125°C
LTC6241HVHS8#PBF LTC6241HVHS8#TRPBF 241HVH 8-Lead Plastic SO –40°C to 125°C
LTC6242CDHC#PBF LTC6242CDHC#TRPBF 6242 16-Lead (5mm × 3mm) Plastic DFN 0°C to 70°C
LTC6242HVCDHC#PBF LTC6242HVCDHC#TRPBF 6242HV 16-Lead (5mm × 3mm) Plastic DFN 0°C to 70°C
LTC6242IDHC#PBF LTC6242IDHC#TRPBF 6242 16-Lead (5mm × 3mm) Plastic DFN –40°C to 85°C
LTC6242HVIDHC#PBF LTC6242HVIDHC#TRPBF 6242HV 16-Lead (5mm × 3mm) Plastic DFN –40°C to 85°C
LTC6242CGN#PBF LTC6242CGN#TRPBF 6242 16-Lead Plastic SSOP 0°C to 70°C
LTC6242HVCGN#PBF LTC6242HVCGN#TRPBF 6242HV 16-Lead Plastic SSOP 0°C to 70°C
LTC6242IGN#PBF LTC6242IGN#TRPBF 6242I 16-Lead Plastic SSOP –40°C to 85°C
LTC6242HVIGN#PBF LTC6242HVIGN#TRPBF 242HVI 16-Lead Plastic SSOP –40°C to 85°C
LTC6242HGN#PBF LTC6242HGN#TRPBF 6242H 16-Lead Plastic SSOP –40°C to 125°C
LTC6242HVHGN#PBF LTC6242HVHGN#TRPBF 242HVH 16-Lead Plastic SSOP –40°C to 125°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based fi nish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/
ORDER INFORMATION
LTC6240/LTC6241 / LTC6242 L7LJCUEN2
LTC6240/LTC6241/LTC6242
4
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AVAILABLE OPTIONS
PART NUMBER AMPS/PACKAGE SPECIFIED TEMP RANGE SPECIFIED SUPPLY VOLTAGE PACKAGE PART MARKING
LTC6240CS5 1 0°C to 70°C 3V, 5V SOT-23 LTCRR
LTC6240CS8 1 0°C to 70°C 3V, 5V SO-8 6240
LTC6240HVCS5 1 0°C to 70°C 3V, 5V, ±5V SOT-23 LTCRS
LTC6240HVCS8 1 0°C to 70°C 3V, 5V, ±5V SO-8 6240HV
LTC6240IS5 1 –40°C to 85°C 3V, 5V SOT-23 LTCRR
LTC6240IS8 1 –40°C to 85°C 3V, 5V SO-8 6240I
LTC6240HVIS5 1 –40°C to 85°C 3V, 5V, ±5V SOT-23 LTCRS
LTC6240HVIS8 1 –40°C to 85°C 3V, 5V, ±5V SO-8 240HVI
LTC6240HS5 1 –40°C to 125°C 3V, 5V SOT-23 LTCRR
LTC6240HS8 1 –40°C to 125°C 3V, 5V SO-8 6240H
LTC6240HVHS5 1 –40°C to 125°C 3V, 5V, ±5V SOT-23 LTCRS
LTC6240HVHS8 1 –40°C to 125°C 3V, 5V, ±5V SO-8 240HVH
LTC6241CS8 2 0°C to 70°C 3V, 5V SO-8 6241
LTC6241CDD 2 0°C to 70°C 3V, 5V DD LBPD
LTC6241HVCS8 2 0°C to 70°C 3V, 5V, ±5V SO-8 6241HV
LTC6241HVCDD 2 0°C to 70°C 3V, 5V, ±5V DD LBRR
LTC6241IS8 2 –40°C to 85°C 3V, 5V SO-8 6241I
LTC6241IDD 2 –40°C to 85°C 3V, 5V DD LBPD
LTC6241HVIS8 2 –40°C to 85°C 3V, 5V, ±5V SO-8 241HVI
LTC6241HVIDD 2 –40°C to 85°C 3V, 5V, ±5V DD LBRR
LTC6241HS8 2 –40°C to 125°C 3V, 5V SO-8 6241H
LTC6241HVHS8 2 –40°C to 125°C 3V, 5V, ±5V SO-8 241HVH
LTC6242CGN 4 0°C to 70°C 3V, 5V GN 6242
LTC6242CDHC 4 0°C to 70°C 3V, 5V DHC 6242
LTC6242HVCGN 4 0°C to 70°C 3V, 5V, ±5V GN 6242HV
LTC6242HVCDHC 4 0°C to 70°C 3V, 5V, ±5V DHC 6242HV
LTC6242IGN 4 –40°C to 85°C 3V, 5V GN 6242I
LTC6242IDHC 4 –40°C to 85°C 3V, 5V DHC 6242
LTC6242HVIGN 4 –40°C to 85°C 3V, 5V, ±5V GN 242HVI
LTC6242HVIDHC 4 –40°C to 85°C 3V, 5V, ±5V DHC 6242HV
LTC6242HGN 4 –40°C to 125°C 3V, 5V GN 6242H
LTC6242HVHGN 4 –40°C to 125°C 3V, 5V, ±5V GN 242HVH
LTC6240/ LTC6241 /LTC6242 L7 LJUW
LTC6240/LTC6241/LTC6242
5
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ELECTRICAL CHARACTERISTICS
(LTC6240C/I, LTC6240HVC/I, LTC6241C/I, LTC6241HVC/I, LTC6242C/I,
LTC6242HVC/I) The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at
TA = 25°C. VS = 5V, 0V, VCM = 2.5V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage (Note 4) LTC6241 S8
0°C to 70°C
–40°C to 85°C
l
l
40 125
250
300
µV
µV
µV
LTC6242 GN
0°C to 70°C
–40°C to 85°C
l
l
50 150
275
300
µV
µV
µV
LTC6240
0°C to 70°C
–40°C to 85°C
l
l
50 175
300
350
µV
µV
µV
LTC6241 DD, LTC6242 DHC
0°C to 70°C
–40°C to 85°C
l
l
100 550
650
725
µV
µV
µV
VOS Match Channel-to-Channel (Note 5) LTC6241 S8
0°C to 70°C
–40°C to 85°C
l
l
40 160
300
375
µV
µV
µV
LTC6242 GN
0°C to 70°C
–40°C to 85°C
l
l
50 185
325
400
µV
µV
µV
LTC6241 DD, LTC6242 DHC
0°C to 70°C
–40°C to 85°C
l
l
150 650
700
750
µV
µV
µV
TC VOS Input Offset Voltage Drift (Note 6) l0.7 2.5 µV/°C
IBInput Bias Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 75 pA
pA
LTC6240
l
0.2 1
75 pA
pA
IOS Input Offset Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 75 pA
pA
LTC6240
l
0.2 1
75 pA
pA
Input Noise Voltage 0.1Hz to 10Hz 550 nVP-P
enInput Noise Voltage Density f = 1kHz 7 10 nV/√Hz
inInput Noise Current Density (Note 8) 0.56 fA/√Hz
RIN Input Resistance Common Mode 1012
CIN Input Capacitance
Differential Mode
Common Mode
f = 100kHz 3.5
3pF
pF
VCM Input Voltage Range Guaranteed by CMRR l0 3.5 V
CMRR Common Mode Rejection 0V ≤ VCM ≤ 3.5V l80 105 dB
CMRR Match
Channel-to-Channel (Note 5) l76 95 dB
LTC6240/LTC6241 / LTC6242 L7LJCUEN2
LTC6240/LTC6241/LTC6242
6
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SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
AVOL Large Signal Voltage Gain VO = 1V to 4V
RL = 10k to VS/2
0°C to 70°C
–40°C to 85°C
l
l
425
300
200
1600 V/mV
V/mV
V/mV
VO = 1.5V to 3.5V
RL = 1k to VS/2
0°C to 70°C
–40°C to 85°C
l
l
90
60
50
215 V/mV
V/mV
V/mV
VOL Output Voltage Swing Low (Note 9) No Load
ISINK = 1mA
ISINK = 5mA
l
l
l
7
40
190
30
75
325
mV
mV
mV
VOH Output Voltage Swing High (Note 9) No Load
ISOURCE = 1mA
ISOURCE = 5mA
l
l
l
11
45
190
30
75
325
mV
mV
mV
PSRR Power Supply Rejection VS = 2.8V to 6V, VCM = 0.2V l80 104 dB
PSRR Match
Channel-to-Channel (Note 5) l74 100 dB
Minimum Supply Voltage (Note 10) l2.8 V
ISC Short-Circuit Current l15 30 mA
ISSupply Current per Amplifi er LTC6241, LTC6242
0°C to 70°C
–40°C to 85°C
l
l
1.8 2.2
2.3
2.4
mA
mA
mA
LTC6240
0°C to 70°C
–40°C to 85°C
l
l
2 2.4
2.5
2.6
mA
mA
mA
GBW Gain Bandwidth Product Frequency = 20kHz, RL = 1k l13 18 MHz
SR Slew Rate (Note 11) AV = –2, RL = 1k l5 10 V/µs
FPBW Full Power Bandwidth (Note 12) VOUT = 3VP-P, RL = 1k l0.53 1.06 MHz
tsSettling Time VSTEP = 2V, AV = –1, RL = 1k, 0.1% 1100 ns
ELECTRICAL CHARACTERISTICS
(LTC6240C/I, LTC6240HVC/I, LTC6241C/I, LTC6241HVC/I, LTC6242C/I,
LTC6242HVC/I) The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at
TA = 25°C. VS = 5V, 0V, VCM = 2.5V unless otherwise noted.
LTC6240/ LTC6241 /LTC6242 L7 LJUW
LTC6240/LTC6241/LTC6242
7
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ELECTRICAL CHARACTERISTICS
(LTC6240C/I, LTC6240HVC/I, LTC6241C/I, LTC6241HVC/I, LTC6242C/I,
LTC6242HVC/I) The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at
TA = 25°C. VS = 3V, 0V, VCM = 1.5V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage (Note 4) LTC6241 S8
0°C to 70°C
–40°C to 85°C
l
l
40 175
275
325
µV
µV
µV
LTC6242 GN
0°C to 70°C
–40°C to 85°C
l
l
60 200
275
325
µV
µV
µV
LTC6240
0°C to 70°C
–40°C to 85°C
l
l
50 200
325
375
µV
µV
µV
LTC6241 DD, LTC6242 DHC
0°C to 70°C
–40°C to 85°C
l
l
100 550
650
725
µV
µV
µV
VOS Match Channel-to-Channel (Note 5) LTC6241 S8
0°C to 70°C
–40°C to 85°C
l
l
40 200
325
400
µV
µV
µV
LTC6242 GN
0°C to 70°C
–40°C to 85°C
l
l
60 225
325
400
µV
µV
µV
LTC6241 DD, LTC6242 DHC
0°C to 70°C
–40°C to 85°C
l
l
150 650
700
750
µV
µV
µV
TC VOS Input Offset Voltage Drift (Note 6) l0.7 2.5 µV/°C
IBInput Bias Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 75 pA
pA
LTC6240
l
0.2 1
75 pA
pA
IOS Input Offset Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 75 pA
pA
LTC6240
l
0.2 1
75 pA
pA
VCM Input Voltage Range Guaranteed by CMRR l0 1.5 V
CMRR Common Mode Rejection 0V ≤ VCM ≤ 1.5V l78 100 dB
CMRR Match
Channel-to-Channel (Note 5) l76 95 dB
AVOL Large Signal Voltage Gain VO = 1V to 2V
RL = 10k to VS/2
0°C to 70°C
–40°C to 85°C
l
l
140
100
75
600 V/mV
V/mV
V/mV
VOL Output Voltage Swing Low (Note 9) No Load
ISINK = 1mA
l
l
3
65 30
110 mV
mV
VOH Output Voltage Swing High (Note 9) No Load
ISOURCE = 1mA
l
l
4
70 30
120 mV
mV
PSRR Power Supply Rejection VS = 2.8V to 6V, VCM = 0.2V l80 104 dB
PSRR Match
Channel-to-Channel (Note 5) l74 100 dB
Minimum Supply Voltage (Note 10) l2.8 V
ISC Short-Circuit Current l36 mA
LTC6240/LTC6241 / LTC6242 L7LJCUEN2
LTC6240/LTC6241/LTC6242
8
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SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage (Note 4) LTC6241 S8
0°C to 70°C
–40°C to 85°C
l
l
50 175
275
325
µV
µV
µV
LTC6242 GN
0°C to 70°C
–40°C to 85°C
l
l
60 200
275
325
µV
µV
µV
LTC6240
0°C to 70°C
–40°C to 85°C
l
l
60 250
350
400
µV
µV
µV
LTC6241 DD, LTC6242 DHC
0°C to 70°C
–40°C to 85°C
l
l
100 550
650
725
µV
µV
µV
VOS Match Channel-to-Channel (Note 5) LTC6241 S8
0°C to 70°C
–40°C to 85°C
l
l
50 200
325
400
µV
µV
µV
LTC6242 GN
0°C to 70°C
–40°C to 85°C
l
l
60 225
325
400
µV
µV
µV
LTC6241 DD, LTC6242 DHC
0°C to 70°C
–40°C to 85°C
l
l
150 650
700
750
µV
µV
µV
TC VOS Input Offset Voltage Drift (Note 6) l0.7 2.5 µV/°C
IBInput Bias Current (Notes 4, 7) LTC6241, LTC6242
l
0.5 75 pA
pA
LTC6240
l
0.5 1
75 pA
pA
IOS Input Offset Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 75 pA
pA
LTC6240
l
0.2 1
75 pA
pA
Input Noise Voltage 0.1Hz to 10Hz 550 nVP-P
(LTC6240HVC/I, LTC6241HVC/I, LTC6242HVC/I) The l denotes the specifi cations which apply over the full operating temperature
range, otherwise specifi cations are at TA = 25°C. VS = ±5V, 0V, VCM = 0V unless otherwise noted.
ELECTRICAL CHARACTERISTICS
(LTC6240C/I, LTC6240HVC/I, LTC6241C/I, LTC6241HVC/I, LTC6242C/I,
LTC6242HVC/I) The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at
TA = 25°C. VS = 3V, 0V, VCM = 1.5V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
ISSupply Current per Amplifi er LTC6241, LTC6242
0°C to 70°C
–40°C to 85°C
l
l
1.4 1.7
1.8
1.9
mA
mA
mA
LTC6240
0°C to 70°C
–40°C to 85°C
l
l
1.5 1.9
2
2.1
mA
mA
mA
GBW Gain Bandwidth Product Frequency = 20kHz, RL = 1k l12 17 MHz
LTC6240/ LTC6241 /LTC6242 L7 LJUW
LTC6240/LTC6241/LTC6242
9
624012fe
ELECTRICAL CHARACTERISTICS
(LTC6240HVC/I, LTC6241HVC/I, LTC6242HVC/I) The l denotes the
specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VS = ±5V, 0V, VCM = 0V
unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
enInput Noise Voltage Density f = 1kHz 7 10 nV/√Hz
inInput Noise Current Density (Note 8) 0.56 fA/√Hz
RIN Input Resistance Common Mode 1012
CIN Input Capacitance
Differential Mode
Common Mode
f = 100kHz 3.5
3pF
pF
VCM Input Voltage Range Guaranteed by CMRR l–5 3.5 V
CMRR Common Mode Rejection –5V ≤ VCM ≤ 3.5V l83 105 dB
CMRR Match
Channel-to-Channel (Note 5) l76 95 dB
AVOL Large Signal Voltage Gain VO = –3.5V to 3.5V
RL = 10k
0°C to 70°C
–40°C to 85°C
l
l
775
600
500
2700 V/mV
V/mV
V/mV
RL = 1k
0°C to 70°C
–40°C to 85°C
l
l
150
90
75
360 V/mV
V/mV
V/mV
VOL Output Voltage Swing Low (Note 9) No Load
ISINK = 1mA
ISINK = 10mA
l
l
l
15
45
360
30
75
550
mV
mV
mV
VOH Output Voltage Swing High (Note 9) No Load
ISOURCE = 1mA
ISOURCE = 10mA
l
l
l
15
45
360
30
75
550
mV
mV
mV
PSRR Power Supply Rejection VS = 2.8V to 11V, VCM = 0.2V l85 110 dB
PSRR Match
Channel-to-Channel (Note 5) l82 106 dB
Minimum Supply Voltage (Note 10) l2.8 V
ISC Short-Circuit Current l15 35 mA
ISSupply Current per Amplifi er LTC6241, LTC6242
0°C to 70°C
–40°C to 85°C
l
l
2.5 3.2
3.3
3.7
mA
mA
mA
LTC6240
0°C to 70°C
–40°C to 85°C
l
l
2.7 3.3
3.4
3.8
mA
mA
mA
GBW Gain Bandwidth Product Frequency = 20kHz, RL = 1k l13 18 MHz
SR Slew Rate (Note 11) AV = –2, RL = 1k l5.5 10 V/µs
FPBW Full Power Bandwidth (Note 12) VOUT = 3VP-P
, RL = 1k l0.58 1.06 MHz
tsSettling Time VSTEP = 2V, AV = –1, RL = 1k, 0.1% 900 ns
LTC6240/LTC6241 / LTC6242
LTC6240/LTC6241/LTC6242
10
624012fe
(LTC6240H/LTC6240HVH, LTC6241H/LTC6241HVH, LTC6242H/LTC6242HVH)
The l denotes the specifi cations which apply from –40°C to 125°C, otherwise specifi cations are at TA = 25°C. VS = 5V, 0V, VCM = 2.5V
unless otherwise noted.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage (Note 4) LTC6241 S8
l
40 125
400 µV
µV
LTC6242 GN
l
50 150
400 µV
µV
LTC6240
l
50 175
450 µV
µV
VOS Match Channel-to-Channel (Note 5) LTC6241 S8
l
40 160
400 µV
µV
LTC6242 GN
l
50 185
400 µV
µV
TC VOS Input Offset Voltage Drift (Note 6) l0.7 2.5 µV/°C
IBInput Bias Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 1.5 pA
nA
LTC6240
l
0.2 1
2.5 pA
nA
IOS Input Offset Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 150 pA
pA
LTC6240
l
0.2 1
750 pA
pA
VCM Input Voltage Range Guaranteed by CMRR l0 3.5 V
CMRR Common Mode Rejection 0V ≤ VCM ≤ 3.5V l78 dB
CMRR Match
Channel-to-Channel (Note 5) l74 dB
AVOL Large Signal Voltage Gain VO = 1V to 4V
RL = 10k to VS/2
l
425
200 1600 V/mV
V/mV
VO = 1.5V to 3.5V
RL = 1k to VS/2
l
90
40 215 V/mV
V/mV
VOL Output Voltage Swing Low (Note 9) No Load
ISINK = 1mA
ISINK = 5mA
l
l
l
30
85
325
mV
mV
mV
VOH Output Voltage Swing High (Note 9) No Load
ISOURCE = 1mA
ISOURCE = 5mA
l
l
l
30
85
325
mV
mV
mV
PSRR Power Supply Rejection VS = 2.8V to 6V, VCM = 0.2V l78 dB
PSRR Match
Channel-to-Channel (Note 5) l74 dB
Minimum Supply Voltage (Note 10) l2.8 V
ISC Short-Circuit Current l15 mA
ISSupply Current per Amplifi er LTC6241, LTC6242
l
1.8 2.2
2.4 mA
mA
LTC6240
l
2 2.4
2.8 mA
mA
GBW Gain Bandwidth Product Frequency = 20kHz, RL = 1k l12 MHz
SR Slew Rate (Note 11) AV = –2, RL = 1k l4.5 V/µs
FPBW Full Power Bandwidth (Note 12) VOUT = 3VP-P, RL = 1k l0.48 MHz
LTC6240/ LTC6241 /LTC6242 L7 LJUW
LTC6240/LTC6241/LTC6242
11
624012fe
ELECTRICAL CHARACTERISTICS
(LTC6240H/LTC6240HVH, LTC6241H/LTC6241HVH, LTC6242H/LTC6242HVH)
The l denotes the specifi cations which apply from –40°C to 125°C, otherwise specifi cations are at TA = 25°C. VS = 3V, 0V, VCM = 1.5V
unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage (Note 4) LTC6241 S8
l
40 175
400 µV
µV
LTC6242 GN
l
60 200
400 µV
µV
LTC6240
l
50 200
450 µV
µV
VOS Match Channel-to-Channel (Note 5) LTC6241 S8
l
40 200
400 µV
µV
LTC6242 GN
l
60 225
400 µV
µV
TC VOS Input Offset Voltage Drift (Note 6) l0.7 2.5 µV/°C
IBInput Bias Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 1.5 pA
nA
LTC6240
l
0.2 1
2.5 pA
nA
IOS Input Offset Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 150 pA
pA
LTC6240
l
0.2 1
750 pA
pA
VCM Input Voltage Range Guaranteed by CMRR l0 1.5 V
CMRR Common Mode Rejection 0V ≤ VCM ≤ 1.5V l75 dB
CMRR Match
Channel-to-Channel (Note 5) l74 dB
AVOL Large Signal Voltage Gain VO = 1V to 2V
RL = 10k to VS/2
l
140
65 600 V/mV
V/mV
VOL Output Voltage Swing Low (Note 9) No Load
ISINK = 1mA
l
l
30
130 mV
mV
VOH Output Voltage Swing High (Note 9) No Load
ISOURCE = 1mA
l
l
30
130 mV
mV
PSRR Power Supply Rejection VS = 2.8V to 6V, VCM = 0.2V l78 dB
PSRR Match Channel-to-Channel
(Note 5) l74 dB
Minimum Supply Voltage (Note 10) l2.8 V
ISC Short-Circuit Current l2.5 mA
ISSupply Current per Amplifi er LTC6241, LTC6242
l
1.4 1.7
1.9 mA
mA
LTC6240
l
1.5 1.9
2.1 mA
mA
GBW Gain Bandwidth Product Frequency = 20kHz, RL = 1k l10 MHz
LTC6240/LTC6241 / LTC6242 L7LJCUEN2
LTC6240/LTC6241/LTC6242
12
624012fe
(LTC6240HVH/LTC6241HVH/LTC6242HVH) The l denotes the specifi cations
which apply from –40°C to 125°C, otherwise specifi cations are at TA = 25°C. VS = ±5V, VCM = 0V unless otherwise noted.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage (Note 4) LTC6241 S8
l
50 175
400 µV
µV
LTC6242 GN
l
60 200
400 µV
µV
LTC6240
l
60 250
450 µV
µV
VOS Match Channel-to-Channel (Note 5) LTC6241 S8
l
50 200
400 µV
µV
LTC6242 GN
l
60 225
400 µV
µV
TC VOS Input Offset Voltage Drift (Note 6) l0.7 2.5 µV/°C
IBInput Bias Current (Notes 4, 7) LTC6241, LTC6242
l
0.5 1.5 pA
nA
LTC6240
l
0.5 1
2.5 pA
nA
IOS Input Offset Current (Notes 4, 7) LTC6241, LTC6242
l
0.2 150 pA
pA
LTC6240
l
0.2 1
750 pA
pA
VCM Input Voltage Range Guaranteed by CMRR l–5 3.5 V
CMRR Common Mode Rejection –5V ≤ VCM ≤ 3.5V l80 dB
CMRR Match
Channel-to-Channel (Note 5) l76 dB
AVOL Large Signal Voltage Gain VO = –3.5V to 3.5V
RL = 10k
l
775
350 2700 V/mV
V/mV
RL = 1k
l
150
60 360 V/mV
V/mV
VOL Output Voltage Swing Low (Note 9) No Load
ISINK = 1mA
ISINK = 10mA
l
l
l
30
85
600
mV
mV
mV
VOH Output Voltage Swing High (Note 9) No Load
ISOURCE = 1mA
ISOURCE = 10mA
l
l
l
30
85
600
mV
mV
mV
PSRR Power Supply Rejection VS = 2.8V to 11V, VCM = 0.2V l83 dB
PSRR Match
Channel-to-Channel (Note 5) l82 dB
Minimum Supply Voltage (Note 10) l2.8 V
ISC Short-Circuit Current l15 mA
ISSupply Current per Amplifi er LTC6241, LTC6242
l
2.5 3.2
3.7 mA
mA
LTC6240
l
2.7 3.3
3.8 mA
mA
GBW Gain Bandwidth Product Frequency = 20kHz, RL = 1k l12 MHz
SR Slew Rate (Note 11) AV = –2, RL = 1k l5 V/µs
FPBW Full Power Bandwidth (Note 12) VOUT = 3VP-P, RL = 1k l0.53 MHz
LTC6240/ LTC6241 /LTC6242 L7 LJUW
LTC6240/LTC6241/LTC6242
13
624012fe
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: A heat sink may be required to keep the junction temperature
below the absolute maximum rating when the output is shorted
indefi nitely.
Note 3: The LTC6240C/LTC6240HVC/LTC6241C/LTC6241HVC, LTC6242C/
LTC6242HVC are guaranteed to meet specifi ed performance from 0°C to
70°C. They are designed, characterized and expected to meet specifi ed
performance from –40°C to 85°C, but are not tested or QA sampled at
these temperatures. The LTC6240I/LTC6240HVI, LTC6241I/LTC6241HVI,
LTC6242I/LTC6242HVI are guaranteed to meet specifi ed performance
from –40°C to 85°C. All versions of the LTC6240H/LTC6241H/LTC6242H
are guaranteed to meet specifi ed performance from –40°C to 125°C.
Note 4: ESD (Electrostatic Discharge) sensitive device. ESD protection
devices are used extensively internal to the LTC6240/LTC6241/LTC6242;
however, high electrostatic discharge can damage or degrade the device.
Use proper ESD handling precautions.
Note 5: Matching parameters are the difference between the two amplifi ers
A and D and between B and C of the LTC6242; between the two amplifi ers
of the LTC6241. CMRR and PSRR match are defi ned as follows: CMRR
and PSRR are measured in µV/V on the matched amplifi ers. The difference
is calculated between the matching sides in µV/V. The result is converted
to dB.
Note 6: This parameter is not 100% tested.
Note 7: Bias current at TA = 25°C is 100% tested and guaranteed for the
LTC6240 in the S8 package. The LTC6240S5, LTC6241 and LTC6242 are
expected to achieve the same performance as the LTC6240S8. All parts are
guaranteed to meet specifi cations over temperature.
Note 8: Current noise is calculated from the formula: in = (2qIB)1/2 where
q = 1.6 × 10–19 coulomb. The noise of source resistors up to 50G
dominates the contribution of current noise. See also Typical Performance
Characteristics curve Noise Current vs Frequency.
Note 9: Output voltage swings are measured between the output and
power supply rails.
Note 10: Minimum supply voltage is guaranteed by the power supply
rejection ratio test.
Note 11: Slew rate is measured in a gain of –2 with RF = 1k and RG =
500. On the LTC6240/LTC6241/LTC6242, VS = ±2.5V, VIN is ±1V and
VOUT slew rate is measured between –1V and +1V. On the LTC6240HV/
LTC6241HV/LTC6242HV, VIN is ±2V and VOUT slew rate is measured
between –2V and +2V.
Note 12: Full-power bandwidth is calculated from the slew rate:
FPBW = SR/πVP-P.
ELECTRICAL CHARACTERISTICS
LTC6240/LTC6241 / LTC6242 L7LJCUEN2
LTC6240/LTC6241/LTC6242
14
624012fe
Input Bias Current
vs Common Mode Voltage
VOS Distribution LTC6241 VOS Distribution LTC6241
VOS Temperature Coeffi cient
Distribution LTC6241
Supply Current vs Supply Voltage
Offset Voltage
vs Input Common Mode Voltage
Input Bias Current
vs Common Mode Voltage
VOS Temperature Coeffi cient
Distribution LTC6240VOS Distribution LTC6240
TYPICAL PERFORMANCE CHARACTERISTICS
INPUT OFFSET VOLTAGE (µV)
0
NUMBER OF UNITS
10
30
40
50
90
6241 G01
20
60
70
80
–70 –50 –30 –10 7030 5010
VS = ±2.5V
SO-8 PACKAGE
INPUT OFFSET VOLTAGE (µV)
0
NUMBER OF UNITS
40
120
6241 G02
20
60
100
80
–350 –250 –150 –50 350150 25050
VS = ±2.5V
DD PACKAGE
DISTRIBUTION (µV/°C)
0
NUMBER OF UNITS
4
16
14
12
6241 G03
2
6
10
8
–1.0 –0.6 –0.2 0.2 1.81.0 1.40.6
VS = ±2.5V
2 LOTS
–55°C TO 125°C
INPUT OFFSET VOLTAGE (µV)
0
PERCENT OF UNITS
5
10
15
35
6241 G04
20
25
30
–70–90–110 –50 –30 –10 7030 5010
VS = ±2.5V
DISTRIBUTION (µV/°C)
0
NUMBER OF UNITS
2
6
8
10
18
6241 G05
4
12
14
16
–0.6 –0.2 1.81.41.00.60.2
VS = 5V, 0
VCM = 2.5V
2 LOTS
–40°C TO 125°C
SO-8 AND SOT23
PACKAGES
TOTAL SUPPLY VOLTAGE (V)
0
2.0
2.5
3.0
610
6241 G06
1.5
1.0
24 812
0.5
0
SUPPLY CURRENT PER AMP (mA)
3.5
TA = –55°C
TA = 125°C
TA = 25°C
INPUT COMMON MODE VOLTAGE (V)
–0.5
OFFSET VOLTAGE (µV)
300
200
250
150
100
0
50
–50
–100
–150
–200
–250
–300 3.0
6241 G07
0 0.5 1.5 2.5 3.5
1.0 2.0 4.54.0
VS = 5V, 0V
TA = –55°C
TA = 125°C
TA = 25°C
COMMON MODE VOLTAGE (V)
0 1.0 2.0 3.0 4.00.5 1.5 2.5 3.5 4.5 5.0
INPUT BIAS CURRENT (pA)
1000
100
10
0.1
1
6241 G08
VS = 5V, 0V
TA = 85°C
TA = 125°C
TA = 25°C
COMMON MODE VOLTAGE (V)
–0.8 –0.6 –0.2 0.2 0.6–0.4 0 0.4 0.8 1.0
INPUT BIAS CURRENT (pA)
700
100
200
300
400
500
600
–400
–300
–200
–100
0
6241 G09
VS = 5V, 0V
TA = 85°C
TA = 125°C
TA = 25°C
LTC6240/ LTC6241 /LTC6242 L7 LJUW
LTC6240/LTC6241/LTC6242
15
624012fe
Output Saturation Voltage
vs Load Current (Output High)
Gain Bandwidth and Phase
Margin vs Temperature Open Loop Gain vs Frequency
Input Bias Current vs Temperature
Output Saturation Voltage
vs Load Current (Output Low)
Gain Bandwidth and Phase
Margin vs Supply Voltage
Slew Rate vs Temperature
Common Mode Rejection Ratio
vs FrequencyOutput Impedance vs Frequency
TYPICAL PERFORMANCE CHARACTERISTICS
TEMPERATURE (°C)
25 45 65 85 10535 55 75 95 115 125
INPUT BIAS CURRENT (pA)
6241 G10
VCM = VS/2
VS = 5V
VS = 10V
1000
100
10
0.1
1
LOAD CURRENT (mA)
0.01
OUTPUT LOW SATURATION VOLTAGE (V)
0.1
0.1 10 100
6241 G11
0.001 1
10
1
VS = 5V, 0V
TA = 125°C
TA = –55°C
TA = 25°C
LOAD CURRENT (mA)
OUTPUT HIGH SATURATION VOLTAGE (V)
0.1
0.1 10 100
6241 G12
0.01 1
10
1
VS = 5V, 0V
TA = 125°C
TA = –55°C
TA = 25°C
TEMPERATURE (°C)
–55 –35 5 45 85–15 25 65 105 125
GAIN BANDWIDTH (MHz)
PHASE MARGIN (DEG)
70
30
40
50
60
0
10
20
30
40
6241 G13
CL = 5pF
RL = 1k
PHASE MARGIN
GAIN BANDWIDTH
VS = ±1.5V
VS = ±5V
VS = ±1.5V
VS = ±5V
FREQUENCY (Hz)
10k 100k 10M1M 100M
GAIN (dB)
PHASE (DEG)
–20
0
–10
10
20
30
40
50
60
70
80
–80
–40
–60
–20
0
20
40
60
80
100
120
6241 G14
CL = 5pF
RL = 1k
VCM = VS/2
PHASE
GAIN
VS = ±1.5V
VS = ±5V
VS = ±1.5V
VS = ±5V
TOTAL SUPPLY VOLTAGE (V)
0482 6 10 12
GAIN BANDWIDTH (MHz)
PHASE MARGIN (DEG)
70
60
40
50
0
10
20
30
6241 G15
TA = 25°C
CL = 5pF
RL = 1k
PHASE MARGIN
GAIN BANDWIDTH
TEMPERATURE (°C)
–55 –35 5 45 85–15 25 65 105 125
SLEW RATE (V/µs)
4
6
8
10
12
14
16
18
20
6241 G16
AV = –2
RF = 1k, RG = 500Ω
CONDITIONS: SEE NOTE 12
VS = ±5V RISING
VS = ±5V FALLING
VS = ±2.5V FALLING
VS = ±2.5V RISING
FREQUENCY (Hz)
OUTPUT IMPEDANCE (Ω)
10k 1M 10M
6241 G17
100k
TA = 25°C
VS = ±2.5V
AV = 10
AV = 1
0.01
10
10k
1
0.10
100
1k
AV = 2
FREQUENCY (Hz)
10k 100k 10M1M 100M
COMMON MODE REJECTION (dB)
–10
0
10
20
30
40
50
60
70
100
90
80
6241 G18
TA = 25°C
VS = ±2.5V
LTC6240/LTC6241 / LTC6242 SDURCWG 1,1755" L7LJCUEN2
LTC6240/LTC6241/LTC6242
16
624012fe
Input Capacitance vs Frequency
Minimum Supply Voltage Output Short-Circuit Current
vs Power Supply Voltage Open Loop Gain
Open Loop Gain Open Loop Gain
Channel Separation vs Frequency Power Supply Rejection Ratio
vs Frequency
Offset Voltage vs Output Current
TYPICAL PERFORMANCE CHARACTERISTICS
POWER SUPPLY REJECTION RATIO (dB)
90
80
70
60
50
40
30
20
10
01k 100k 1M 100M10k 10M
FREQUENCY (Hz)
6241 G20
TA = 25°C
VS = ±2.5V
POSITIVE SUPPLY
NEGATIVE SUPPLY
FREQUENCY (Hz)
10k 100k 10M1M 100M
VOLTAGE GAIN (dB)
–120
0
–10
–20
–30
–40
–50
–60
–70
–110
–100
–90
–80
6241 G19
TA = 25°C
VS = ±2.5V
AV = 1
INPUT CAPACITANCE (pF)
16
14
12
10
8
6
4
2
01k 100k 1M 100M10k 10M
FREQUENCY (Hz)
6241 G21
VS = ±1.5V
CCM
TOTAL SUPPLY VOLTAGE (V)
02 614 8375910
CHANGE IN OFFSET VOLTAGE (µV)
100
20
40
60
80
–100
–80
–40
–60
–20
0
6241 G22
VCM = VS/2
TA = 125°C
TA = –55°C
TA = 25°C
POWER SUPPLY VOLTAGE (±V)
1.5 2.5 4.52.0 3.53.0 4.0 5.0
OUTPUT SHORT-CIRCUIT CURRENT (mA)
50
10
20
30
40
–50
–40
–20
–30
–10
0
6241 G23
SOURCING
SINKING
TA = 125°C
TA = 125°C
TA = –55°C
TA = –55°C
TA = 2C
OUTPUT VOLTAGE (V)
0 0.5 2.51.51.0 2.0 3.0
INPUT VOLTAGE (µV)
120
100
20
40
60
80
0
6241 G24
TA = 25°C
VS = 3V, 0V
RL = 100k
RL = 10k
OUTPUT VOLTAGE (V)
012 534
INPUT VOLTAGE (µV)
120
100
20
40
60
80
–20
0
6241 G25
TA = 25°C
VS = 5V, 0V
RL = 1k
RL = 10k
OUTPUT VOLTAGE (V)
–5 –4 0–2–3 –1 51234
INPUT VOLTAGE (µV)
100
20
40
60
80
–60
–40
–20
0
6241 G26
TA = 25°C
VS = ±5V
RL = 1k
RL = 10k
OUTPUT CURRENT (mA)
–50 –40 –30 –20 –10 10 302004050
OFFSET VOLTAGE (µV)
500
400
100
200
300
–500
–400
–300
–100
–200
0
6241 G27
TA = 125°C
TA = –55°C
TA = 25°C
VS = ±5V
LTC6240/ LTC6241 /LTC6242 WW”. \\ / I: \ s 111111 // / ‘\ L7 LJUW
LTC6240/LTC6241/LTC6242
17
624012fe
Warm-Up Drift vs Time Noise Voltage vs Frequency
Series Output Resistance and
Overshoot vs Capacitive Load
Series Output Resistance and
Overshoot vs Capacitive Load
0.1Hz to 10Hz Voltage Noise
Noise Current vs Frequency
Minimum Output Series
Resistance vs Capacitive Load
Settling Time vs Output Step
(Inverting)
Settling Time vs Output Step
(Non-Inverting)
TYPICAL PERFORMANCE CHARACTERISTICS
TIME AFTER POWER UP (s)
010 3020540605015 3525 45 55
CHANGE IN OFFSET VOLTAGE (µV)
25
15
20
–5
0
10
5
6241 G28
TA = 25°C
VS = ±1.5V
VS = ±2.5V
VS = ±5V
FREQUENCY (Hz)
20
10
NOISE VOLTAGE (nV/√Hz)
30
40
50
60
1 100 1k 100k
6241 G29
010 10k
TA = 25°C
VS = ±2.5V
VCM = 0V
TIME (1s/DIV)
VOLTAGE NOISE (200nV/DIV)
6241 G30
VS = 5V, 0V
FREQUENCY (Hz)
1
NOISE CURRENT (fA/√Hz)
10
100 10k 100k
6241 G31
0.1 1k
1000
100
TA = 25°C
VS = ±2.5V
VCM = 0V
CAPACITIVE LOAD (pF)
10
OVERSHOOT (%)
60
50
40
30
20
10
0100 1000
6241 G32
RS = 50Ω
RS = 10Ω
VS = ±2.5V
AV = –1
R
S
1k 1k
C
L
75pF
+
0.01µF 1µF0.1µF1000pF100pF
CAPACITIVE LOAD
1
OUTPUT SERIES RESISTANCE (Ω)
10
10pF 10µF
6241 G33
0.1
1000
100
VS = ±2.5V
<30% OVERSHOOT
CAPACITIVE LOAD (pF)
10
OVERSHOOT (%)
60
50
40
30
20
10
0100 1000
6241 G34
RS = 50Ω
RS = 10Ω
VS = ±2.5V
AV = –2
R
S
500Ω 1k
C
L
75pF
+
OUTPUT STEP (V)
–4 –2 3–3 10–1 2 4
SETTLING TIME (µs)
3.5
1.5
2.0
2.5
3.0
0
0.5
1.0
6241 G35
10mV
1mV
10mV
1mV
TA = 25°C
VS = ±5V
AV = 1
V
OUT
V
IN
1k
+
3.0
1.5
2.0
2.5
0
0.5
1.0
OUTPUT STEP (V)
–4 –2 3–3 10–1 2 4
SETTLING TIME (µs)
6241 G36
10mV
1mV
10mV
1mV
TA = 25°C
VS = ±5V
AV = –1
V
OUT
V
IN
1k
+
1k 1k
LTC6240/LTC6241 / LTC6242 L7Hߤߤ
LTC6240/LTC6241/LTC6242
18
624012fe
Distortion vs Frequency Distortion vs Frequency
Maximum Undistorted Output
Signal vs Frequency
Distortion vs Frequency
Large Signal Response Large Signal Response Output Overdrive Recovery
Small Signal ResponseDistortion vs Frequency
TYPICAL PERFORMANCE CHARACTERISTICS
FREQUENCY (Hz)
10k 100k 1M 10M
OUTPUT VOLTAGE SWINGING (VP-P)
10
7
4
1
8
5
2
9
6
3
6241 G37
TA = 25°C
VS = ±5V
HD2, HD3 < –40dBc
AV = +2
AV = –1
FREQUENCY (Hz)
10k 100k 1M 10M
DISTORTION (dBc)
–30
–60
–90
–100
–50
–80
–40
–70
6241 G38
VS = ±2.5V
AV = 1
VOUT = 2VP-P
RL = 1k, 2ND
RL = 1k, 3RD
FREQUENCY (Hz)
10k 100k 1M 10M
DISTORTION (dBc)
–30
–60
–90
–100
–50
–80
–40
–70
6241 G39
VS = ±5V
AV = 1
VOUT = 2VP-P
RL = 1k, 2ND
RL = 1k, 3RD
FREQUENCY (Hz)
10k 100k 1M 10M
DISTORTION (dBc)
–30
–60
–90
–100
–50
–80
–40
–70
6241 G40
VS = ±2.5V
AV = 2
VOUT = 2VP-P
RL = 1k, 2ND
RL = 1k, 3RD
FREQUENCY (Hz)
10k 100k 1M 10M
DISTORTION (dBc)
–30
–60
–90
–100
–50
–80
–40
–70
6241 G41
VS = ±5V
AV = 2
VOUT = 2VP-P
RL = 1k, 2ND
RL = 1k, 3RD
VS = ±2.5V
AV = 1
RL = ∞
6241 G42
0V
VS = ±5V
AV = 1
RL = ∞
6241 G43
0V
VS = ±2.5V
AV = –1
RL = 1k
6241 G44
0V
VS = ±2.5V
AV = 3
RL = ∞
500ns/DIV 6241 G45
0V
0V
VIN
(1V/DIV)
VOUT
(2V/DIV)
LTCé240/ LTC6241 /LTC6242 %wj"$ 4r H %E i4} L7 LJDW
LTC6240/LTC6241/LTC6242
19
624012fe
Amplifi er Characteristics
Figure 1 is a simplifi ed schematic of the amplifi er, which
has a pair of low noise input transistors M1 and M2. A
simple folded cascode Q1, Q2 and R1, R2 allow the input
stage to swing to the negative rail, while performing level
shift to the differential drive generator. Low offset voltage
is accomplished by laser trimming the input stage.
Capacitor C1 reduces the unity cross frequency and im-
proves the frequency stability without degrading the gain
bandwidth of the amplifi er. Capacitor CM sets the overall
amplifi er gain bandwidth. The differential drive generator
supplies signals to transistors M3 and M4 that swing the
output from rail-to-rail.
The photo of Figure 2 shows the output response to an
input overdrive with the amplifi er connected as a voltage
follower. If the negative going input signal is less than
a diode drop below V, no phase inversion occurs. For
input signals greater than a diode drop below V, limit the
current to 3mA with a series resistor RS to avoid phase
inversion.
ESD
The LTC6240/LTC6241/LTC6242 have reverse-biased ESD
protection diodes on all input and outputs as shown in
Figure 1. If these pins are forced beyond either supply,
unlimited current will fl ow through these diodes. If the
current is transient and limited to one hundred milliamps
or less, no damage to the device will occur.
The amplifi er input bias current is the leakage current of
these ESD diodes. This leakage is a function of the tempera-
ture and common mode voltage of the amplifi er, as shown
in the Typical Performance Characteristics curves.
Noise
The LTC6240/LTC6241/LTC6242 exhibit exceptionally
low 1/f noise in the 0.1Hz to 10Hz region. This 550nVP-P
noise allows these op amps to be used in a wide variety
of high impedance low frequency applications, where
zero-drift amplifi ers might be inappropriate due to their
charge injection.
In the frequency region above 1kHz the LTC6240/LTC6241/
LTC6242 also show good noise voltage performance. In
this frequency region, noise can easily be dominated by
the total source resistance of the particular application.
Specifi cally, these amplifi ers exhibit the noise of a 3.1k
resistor, meaning it is desirable to keep the source and
feedback resistance at or below this value, i.e. RS + RG||RFB
≤ 3.1k. Above this total source impedance, the noise
voltage is not dominated by the amplifi er.
Noise current can be estimated from the expression in =
2qIB, where q = 1.6 • 10–19 coulombs. Equating √4kTRΔf
and R√2qIBΔf shows that for source resistors below 50G
the amplifi er noise is dominated by the source resistance.
See the Typical Performance Characteristics curve Noise
Current vs Frequency.
Figure 1. Simplifi ed Schematic Figure 2. Unity Gain Follower Test Circuit
APPLICATIONS INFORMATION
R2
Q2
6241 F01
VIN+
ITAIL
VIN
VO
V+
V+
V
V
V
CM
DESD5
DIFFERENTIAL
DRIVE
GENERATOR
BIAS
DESD6
V+
DESD2
V+
DESD4
V
DESD1
V
DESD3
R1
Q1
M2M1
M3
M4
C1
CLAMP
+2.5V
–2.5V
6241 F02
+
LTC6240
RS
VIN VOUT
VOUT AND VIN OF FOLLOWER WITH LARGE INPUT OVERDRIVE
VDD =
+2.5V
VSS =
–2.5V
LTC6240/LTC6241 / LTC6242 'Tv'TyTvTv L7LJCUEN2
LTC6240/LTC6241/LTC6242
20
624012fe
Proprietary design techniques are used to obtain simulta-
neous low 1/f noise and low input capacitance. Low input
capacitance is important when the amplifi er is used with
high value source and feedback resistors. High frequency
noise from the amplifi er tail current source, ITAIL in Fig-
ure 1, couples through the input capacitance and appears
across these large source and feedback resistors. As an
example, the photodiode amplifi er of Figure 15 on the last
page of this data sheet shows the noise results from the
LTC6241 and the results of a competitive CMOS amplifi er.
The LTC6241 output is the ideal noise of a 1M resistor
at room temperature, 130nV√Hz.
Half the Noise
The circuit shown in Figure 3 can be used to achieve even
lower noise voltage. By paralleling 4 amplifi ers the noise
voltage can be lowered by √4, or half as much noise. The
comes about from an RMS summing of uncorrelated
noise sources. This circuit maintains extremely high input
resistance, and has a 250 output resistance. For lower
output resistance, a buffer amplifi er can be added without
infl uencing the noise.
Stability
The good noise performance of these op amps can be at-
tributed to large input devices in the differential pair. Above
several hundred kilohertz, the input capacitance rises and
can cause amplifi er stability problems if left unchecked.
When the feedback around the op amp is resistive (RF), a
pole will be created with RF, the source resistance, source
capacitance (RS, CS), and the amplifi er input capacitance.
In low gain confi gurations and with RF and RS in even
the kilohm range (Figure 4), this pole can create excess
phase shift and possibly oscillation. A small capacitor CF
in parallel with RF eliminates this problem.
Low Noise Single-Ended Input to Differential Output
Amplifi er
The circuit on the fi rst page of the data sheet is a low noise
single-ended input to differential output amplifi er, with a
200k input impedance. The very low input bias current
of the LTC6241 allows for these large input and feedback
resistors. The 200k resistors, R1 and R2, along with C1 and
C2 set the –3dB bandwidth to 80kHz. Capacitor C3 is used
to cancel effects of input capacitance, while C4 adds phase
lead to compensate the phase lag of the second amplifi er.
Figure 3. Parallel Amplifi er Lowers Noise by 2x Figure 4. Compensating Input Capacitance
APPLICATIONS INFORMATION
10Ω
6241 F03
+1/4
LTC6242
1k
1k
10Ω
+1/4
LTC6242
1k
1k
10Ω
+1/4
LTC6242
1k
1k
10Ω
+1/4
LTC6242
1k
1k
+2.5
–2.5
VIN VO
+
CIN
CS
6241 F04
RF
RS
OUTPUT
CF
LTC6240/ LTC6241 /LTC6242 L7 LJUW
LTC6240/LTC6241/LTC6242
21
624012fe
The op amp’s good input offset voltage match and low
input bias current means that the typical differential output
offset voltage is less than 40µV. A noise spectrum plot of
the differential output is shown in Figure 5.
The guard ring should extend as far as necessary to shield
the high impedance signal from any and all leakage paths.
Figure 6 shows the use of a guard ring on the LTC6241 in
a unity gain confi guration. In this case the guard ring is
connected to the output and is shielding the high impedance
noninverting input from V. Figure 7 shows the inverting
gain confi guration.
A Digitally Programmable AC Difference Amplifi er
The LTC6241 confi gured as a difference amplifi er, can be
combined with a programmable gain amplifi er (PGA) to
obtain a low noise high speed programmable difference
amplifi er. Figure 8 shows the LTC6241 based as a single-
supply AC amplifi er. One LTC6241 op amp is used at the
circuit’s input as a standard four resistor difference amplifi er.
Figure 5. Differential Output Noise
Achieving Low Input Bias Current
The DD package is leadless and makes contact to the PCB
beneath the package. Solder fl ux used during the attach-
ment of the part to the PCB can create leakage current
paths and can degrade the input bias current performance
of the part. All inputs are susceptible because the backside
paddle is connected to V internally. As the input voltage
changes or if V changes, a leakage path can be formed
and alter the observed input bias current. For lowest bias
current, use the LTC6240/LTC6241 in the SO-8 and provide
a guard ring around the inputs that are tied to a potential
near the input voltage.
Layout Considerations and a PCB Guard Ring
In high source impedance applications such as pH probes,
photodiodes, strain gauges, et cetera, the low input bias
current of these parts requires a clean board layout to
minimize additional leakage current into a high impedance
signal node. A mere 100G of PC board resistance
between a 5V supply trace and an input trace adds 50pA
of leakage current, far greater then the input bias current
of the operational amplifi er. A guard ring around the high
impedance input traces driven by a low impedance source
equal to the input voltage prevents such leakage problems.
Figure 6. Sample Layout. Unity Gain Confi guration, Using Guard
Ring to Shield High Impedance Input from Board Leakage
Figure 7. Sample Layout. Inverting Gain Confi guration, Using
Guard Ring to Shield High Impedance Input from Board Leakage
APPLICATIONS INFORMATION
FREQUENCY (kHz)
020 6010 40 8030 7050 90 100
DIFFERENTIAL OUTPUT VOLTAGE DENSITY (nV/√Hz)
140
60
80
100
120
0
20
40
6241 F05
VS = ±2.5V
TA = 25°C
–3dB BW = 80kHz
LTC6241 S8
R
OUT+
IN
IN+
V
LEAKAGE
CURRENT
NO LEAKAGE
CURRENT
GUARD
RING
NO SOLDER MASK
OVER THE GUARD RING
LTC6241 F06
LTC6241 S8
LTC6241 F07
R
R
OUT+
IN
IN+
V
VIN
GND
LTC6240/LTC6241 / LTC6242 «H: §§ w .E W I» "'1 L7LJCUEN2
LTC6240/LTC6241/LTC6242
22
624012fe
Figure 8. Wideband Difference Amplifi er with High
Input Impedance and Digitally Programmable Gain
The low bias current and current noise of the LTC6241
allow the use of high valued input resistors, 100k or
greater. Resistors R1, R2, R3 and R4 are equal and the
gain of the difference amplifi er is one. An LTC6910-2 PGA
amplifi es the difference amplifi er output with inverting
gains of –1, –2, –4, –8, –16, –32 and –64. The second
LTC6241 op amp is used as an integrator to set the DC
output voltage equal to the LT6650 reference voltage VREF.
The integrator drives the PGA analog ground to provide
a feedback loop, in addition to blocking any DC voltage
through the PGA. The reference voltage of the LT6650
can be set to a voltage from 400mV to V+ – 350mV with
resistors R5 and R6. If R6 is 20k or less, the error due
to the LT6650 op amp bias current is negligible. The low
voltage offset and drift of the LTC6241 integrator will not
contribute any signifi cant error to the LT6650 reference
voltage. The LT6650 VREF voltage has a maximum error
of ±2% with 1% resistors. The upper –3dB frequency of
the amplifi er is set by resistor R3 and capacitor C1 and
is limited by the bandwidth of the PGA when operated at
a gain of 64. Capacitor C2 is equal to C1 and is added to
maintain good common mode rejection at high frequency.
The lower –3dB frequency is set by the integrator resistor
R7, capacitor C3, and the gain setting of the LTC6910-2
PGA. This lower –3dB zero frequency is multiplied by the
PGA gain. The rail-to-rail output of the LTC6910-2 PGA
allows for a maximum output peak-to-peak voltage equal
to twice the VREF voltage. At the maximum gain setting of
64, the maximum peak-to-peak difference between inputs
V1 and V2 is equal to twice VREF divided by 64.
Example Design: Design a programmable gain AC differ-
ence amplifi er, with a bandwidth of at least 10Hz to 100kHz,
an input impedance equal to or greater than 100k, and
an output DC reference equal to 1V.
a. Select input resistors R1, R2, R3 and R4 equal to
100k.
b. If the upper –3dB frequency is 100kHz then C1 = 1/(2π
• R2 • f3dB) = 1/(6.28 • 100k • 100kHz) = 15pF (to
the nearest 5% value) and C2 = C1 = 15pF.
c. Select R7 equal to one 1M and set the lower –3dB
frequency to 10Hz at the highest PGA gain of 64, then
C3 = Gain/(2π • R7 • f3dB) = 64/(6.28 • 100k • 10Hz)
= 1µF. Lower gains settings will give a lower f3dB.
d. Calculate the value of R5 to set the LT6650 reference
equal to 1V;
V
REF = 0.4(R5/R6 + 1), so R5 = R6(2.5VREF – 1). For
R6 = 20k, R5 = 30k
With VREF = 1V the maximum input difference voltage
is equal to 2V/64 = 31.2mV.
40nVpp Noise, 0.05μV/°C Drift, Chopped FET
Amplifi er
Figure 9’s circuit combines the ±5V rail-to-rail performance
of the LTC6241HV with a pair of extremely low noise JFETs
confi gured in a chopper based carrier modulation scheme
APPLICATIONS INFORMATION
6241 F08
R4
R3
R2
+1/2
LTC6241
C1
C2
1µF
0.1µF8 765
G2 G1 G0
1
1
2
234
AGNDOUT IN V
V+
0.1µF
V+
V+
R1
R1 = R2 = R3 = R4
V2
V1
R5
1k
1000pF
3 4
5
R6
20k
LTC6910-2
LT6650
VOUT
VREF
+
1/2
LTC6241
C3 R7
100Ω
1µF
DIGITAL INPUTS
G1G2 GO
GAIN
0
0
1
1
0
0
1
1
0
0
0
0
1
1
1
1
0
1
0
1
0
1
0
1
0
–1
–2
–4
–8
–16
–32
–64
VOUT = (V1 – V2) GAIN + VREF

VR
R
RkV
REF
REF
=+
¥
§
¦´
µ
=

=
04 5
61
510 5 2 R620
.•
•• – k
d BANDWIDTH f f
fRC
HIGH LOW
HIGH
––
•• •
3
1
23
=
=P1273
fGAIN
RC
LOW =•• •P
LTC6240/ LTC6241 /LTC6242 5 L7 LJUW
LTC6240/LTC6241/LTC6242
23
624012fe
Figure 9. Ultralow Noise Chopper Amplifi er
to achieve an extraordinarily low noise and low DC drift.
The performance of this circuit is suited for the demand-
ing transducer signal conditioning situations such as high
resolution scales and magnetic search coils.
The LTC1799’s output is divided down to form a 2-phase
925Hz square wave clock. This frequency, harmonically
unrelated to 60Hz, provides excellent immunity to harmonic
beating or mixing effects which could cause instabilities.
S1 and S2 receive complementary drive, causing A1 to
see a chopped version of the input voltage. A1’s square
wave output is synchronously demodulated by S3 and
S4. Because these switches are synchronously driven
with the input chopper, proper amplitude and polarity
information is presented to A2, the DC output amplifi er.
This stage integrates the square wave into a DC voltage,
providing the output. The output is divided down (R2 and
R1) and fed back to the input chopper where it serves as
a zero signal reference. Gain, in this case 1000, is set by
the R1-R2 ratio. Because A1 is AC coupled, its DC offset
and drift do not affect the overall circuit offset, resulting
in the extremely low offset and drift noted. The JFETs
have an input RC damper that minimizes offset voltage
contribution due to parasitic switch behavior, resulting in
the 1µV offset specifi cation.
APPLICATIONS INFORMATION
+
+
BIAS
10M
F
14
15
16
3
2
1
S4
S3 240k
F
OUTPUT
A2
LTC6241HV
A1
LTC6241HV
F
INPUT
10k
8
7
11
S1
S2
9
6
10
R2
10k
R1
10Ω
NOISE
OFFSET
DRIFT
OPEN-LOOP GAIN
I
= 40nVP-P 0.1Hz TO 10Hz
= 1µV
= 0.05µV/°C
R2
10
= 10
= 500pA
+1
GAIN =
9
0.01µF
Ø1
Ø1
Ø2
Ø2
6241 F09
= 0.1% METAL FILM RESISTOR
= 1% METAL FILM RESISTOR
*
**
= LTC201 QUAD
= LSK389
= LINEAR INTEGRATED SYSTEMS
FREMONT, CA
F
DIV
RSET
LTC1799
V+
74C90 ÷ 10
18.5kHz
OUT 74C74 ÷ 2
TO
Ø1
POINTS
TO
Ø2
POINTS
QQ
54.2k*
TO LTC201 V+ PIN
5V
5V –5V
5V 5V
925Hz
TO LTC201 V PIN
F
898Ω**
5V
–5V
898Ω**
LSK389
30.1Ω
499Ω**
+
+
LTCb240/LTCé241 / LTC6242 L7Hfl§fl§
LTC6240/LTC6241/LTC6242
24
624012fe
by the sensor is forced across the feedback capacitor
by the op amp action. Because the feedback capacitor
is 100 times smaller than the sensor, it will be forced to
100 times what would have been the sensors open circuit
voltage. So the circuit gain is 100. The benefi t of this ap-
proach is that the signal gain of the circuit is independent
of any cable capacitance introduced between the sensor
and the amplifi er. Hence this circuit is favored for remote
accelerometers where the cable length may vary. Diffi culties
with the circuit are inaccuracy of the gain setting with the
small capacitor, and low frequency cutoff due to the bias
resistor working into the small feedback capacitor.
Figure 12 shows a noninverting amplifi er approach. This
approach has many advantages. First of all, the gain is set
accurately with resistors rather than with a small capaci-
tor. Second, the low frequency cutoff is dictated by the
bias resistor working into the large 770pF sensor, rather
than into a small feedback capacitor, for lower frequency
response. Third, the noninverting topology can be paral-
leled and summed (as shown) for scalable reductions in
voltage noise. The only drawback to this circuit is that the
parasitic capacitance at the input reduces the gain slightly.
This circuit is favored in cases where parasitic input
capacitances such as traces and cables will be relatively
small and invariant.
The noise measured over a 50 second interval, in Figure 10,
is 40nV in a 0.1Hz to 10Hz bandwidth.This low noise is at-
tributed to the input JFETs die size and current density.
Figure 11. Classical Inverting Charge Amplifi er Figure 12. Low Noise Noninverting Shock Sensor Amplifi er
Figure 10. Noise in a 0.1Hz to 10Hz Bandwidth
Low Noise Shock Sensor Amplifi ers
Figures 11 and 12 show the amplifi ers realizing two dif-
ferent approaches to amplifying signals from a capacitive
sensor. The sensor in both cases is a 770pF piezoelectric
shock sensor accelerometer, which generates charge under
physical acceleration.
Figure 11 shows the classical “charge amplifi er” approach.
The LTC6240 is in the inverting confi guration so the sensor
looks into a virtual ground. All of the charge generated
APPLICATIONS INFORMATION
5s/DIV 6241 F10
20nV/DIV
BIAS RESISTOR
VISHAY-TECHNO
CRHV2512AF1007G
(OR EQUIVALENT)
MAIN
GAIN-SETTING
ELEMENT IS A
CAPACITOR
SHOCK SENSOR
MURATA-ERIE
PKGS-00LD
770pF
CABLE HAS
UNKNOWN C
Rf
1G
6241 F11
VOUT = 110mV/g
+
LTC6240
Cf
7.7pF
BIAS RESISTOR
VISHAY-TECHNO
CRHV2512AF1007G
(OR EQUIVALENT)
1G
VS+
6241 F12
10k
1k
1k
100Ω
VOUT = 110mV/g
VS = ±1.4V to ±5.5V
BW = 0.2Hz to 10kHz
VOUT
+1/2
LTC6241HV
VS
10k100Ω
+1/2
LTC6241HV
SHOCK SENSOR
MURATA-ERIE
PKGS-00LD
770pF
LTC6240/ LTC6241 /LTC6242 if} L7 LJUW
LTC6240/LTC6241/LTC6242
25
624012fe
1M Transimpedance Amplifi er with 43nV/√Hz
Output Noise
In a normal 1M transimpedance amplifi er, like that shown
on the back page of this data sheet, the output noise density
must be at least 130nV/√Hz at room temperature. This is
true even should the op amp be perfectly noiseless, because
the 1M resistor provides 130nV/√Hz of voltage noise at
room temperature independently of the op amp.
The circuit of Figure 13 provides an overall transimpedance
gain of 1M, but it has an output noise density of only
43nV/√Hz, about 1/3 of the normal transimpedance ampli-
er. It does this by taking a higher initial transimpedance
gain of 10M and then attenuating by a factor of 10. The
transistor section provides voltage gain and works on a
54V supply voltage to guarantee adequate output swing.
By achieving an output swing of 50V before attenuation,
the circuit provides an output swing to 5V after attenu-
ation. The 10M resistor sets the gain of the TIA stage
and has a noise density of 400nV/√Hz. After attenuation,
the effective TIA gain drops to 1M while the noise fl oor
drops to 40nV/√Hz, which clearly dominates the observed
43nV/√Hz. Note the additional benefi t that the offset voltage
of the op amp is divided by 10. Worst-case output offset
for this circuit is 150µV over temperature.
Reference Buffer
Figure 14 shows the LTC6240 being utilized as a buffer
in conjunction with the LT1019 reference. The passive
R-C fi lter attenuates the reference noise and the LTC6240
provides a low noise buffer, resulting in an output noise
of 8nV/√Hz.
Figure 13. 1M Transimpedance Amplifi er with 43nV/√Hz Output Noise
Figure 14. Low Noise Reference Buffer
APPLICATIONS INFORMATION
5V
54V
–5V
–1.5V
3pF
PHOTODIODE
6241 F13
–5V
10k
+
LTC6240HV
100pF
10M
1%
0.3pF
1k
10k 2.4k
33k
MPSA06
43k
9.09k
1%
1/4W
1k
1%
VOUT
1M GAIN
(1V/µA)
10M GAIN
(10V/µA)
MPSA06
5V
–5V
6241 F14
0.2Ω
+
LTC6240HV
1M
10µF
CERAMIC
OR FILM
8nV/√Hz VOUT
F
LT1019-2.5 180nV/√Hz
LTC6240/LTC6241 / LTC6242 DD Package Lead Plastic DFN (3mm x 3mm) Reierence LTC DWG 0‘ 0570871698} ] fififiFfifi 4477177 \lfifiw anatom w 551nm” msmEs; (ZSHJES) \ 0 Q m fl ‘ A ‘ ‘ 1 07513 05 4. <7 l="" +="" l2="" as="" :n="" m="" ~a="" fin="" min="" as="" ammm="" wgwiwosm="" pad="" v="" +="" l7ljcuen2="">
LTC6240/LTC6241/LTC6242
26
624012fe
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
PACKAGE DESCRIPTION
3.00 p0.10
(4 SIDES)
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON TOP AND BOTTOM OF PACKAGE
0.40 p 0.10
BOTTOM VIEW—EXPOSED PAD
1.65 p 0.10
(2 SIDES)
0.75 p0.05
R = 0.125
TYP
2.38 p0.10
14
85
PIN 1
TOP MARK
(NOTE 6)
0.200 REF
0.00 – 0.05
(DD8) DFN 0509 REV C
0.25 p 0.05
2.38 p0.05
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
1.65 p0.05
(2 SIDES)
2.10 p0.05
0.50
BSC
0.70 p0.05
3.5 p0.05
PACKAGE
OUTLINE
0.25 p 0.05
0.50 BSC
LTC6240/ LTC6241 / LTC6242 ‘7 a ‘ W ¢ ‘ luuuuwwufl , ,,,,, w ,,,,, , f, ,,,,,,, i ,,,,, ,7 x \ + i O x mm ‘Han l7:t:I-CI-tZI-CI-CHZHZHZI—iiflmkuflfi Q ‘74, L7 LJUW
LTC6240/LTC6241/LTC6242
27
624012fe
DHC Package
16-Lead Plastic DFN (5mm × 3mm)
(Reference LTC DWG # 05-08-1706)
PACKAGE DESCRIPTION
3.00 ±0.10
(2 SIDES)
5.00 ±0.10
(2 SIDES)
NOTE:
1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDEC
PACKAGE OUTLINE MO-229
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
0.40 ± 0.10
BOTTOM VIEW—EXPOSED PAD
1.65 ± 0.10
(2 SIDES)
0.75 ±0.05
R = 0.115
TYP
R = 0.20
TYP
4.40 ±0.10
(2 SIDES)
18
169
PIN 1
TOP MARK
(SEE NOTE 6)
0.200 REF
0.00 – 0.05
(DHC16) DFN 1103
0.25 ± 0.05
PIN 1
NOTCH
0.50 BSC
4.40 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1.65 ±0.05
(2 SIDES)2.20 ±0.05
0.50 BSC
0.65 ±0.05
3.50 ±0.05
PACKAGE
OUTLINE
0.25 ± 0.05
LTC6240/LTC6241 /LTC6242 IDDDDDDDUT immumm} 7 T7 i EM '1 g1L444, f fifififififififi LEQQQQEQE I 4171$Q£
LTC6240/LTC6241/LTC6242
28
624012fe
PACKAGE DESCRIPTION
GN Package
16-Lead Plastic SSOP (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1641)
GN16 (SSOP) 0204
12
345678
.229 – .244
(5.817 – 6.198)
.150 – .157**
(3.810 – 3.988)
16 15 14 13
.189 – .196*
(4.801 – 4.978)
12 11 10 9
.016 – .050
(0.406 – 1.270)
.015 ± .004
(0.38 ± 0.10) × 45°
0° – 8° TYP
.007 – .0098
(0.178 0.249)
.0532 – .0688
(1.35 – 1.75)
.008 – .012
(0.203 – 0.305)
TYP
.004 – .0098
(0.102 – 0.249)
.0250
(0.635)
BSC
.009
(0.229)
REF
.254 MIN
RECOMMENDED SOLDER PAD LAYOUT
.150 – .165
.0250 BSC.0165 ±.0015
.045 ±.005
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
INCHES
(MILLIMETERS)
NOTE:
1. CONTROLLING DIMENSION: INCHES
2. DIMENSIONS ARE IN
3. DRAWING NOT TO SCALE
L7 LJUW LTC6240/ LTC6241 / LTC6242 $
LTC6240/LTC6241/LTC6242
29
624012fe
S5 Package
5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635 Rev B)
1.50 – 1.75
(NOTE 4)
2.80 BSC
0.30 – 0.45 TYP
5 PLCS (NOTE 3)
DATUM ‘A’
0.09 – 0.20
(NOTE 3) S5 TSOT-23 0302 REV B
PIN ONE
2.90 BSC
(NOTE 4)
0.95 BSC
1.90 BSC
0.80 – 0.90
1.00 MAX
0.01 – 0.10
0.20 BSC
0.30 – 0.50 REF
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
3.85 MAX
0.62
MAX
0.95
REF
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
1.4 MIN
2.62 REF
1.22 REF
PACKAGE DESCRIPTION
LTC6240/LTC6241 /LTC6242 TDJEJEE TH H H H I LDJDDJ T T 4 F 7H H H H We 7 : Li Twang Lwi 1 74‘44 1 L7LJllfiN2
LTC6240/LTC6241/LTC6242
30
624012fe
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
PACKAGE DESCRIPTION
.016 – .050
(0.406 – 1.270)
.010 – .020
(0.254 – 0.508)× 45°
0°– 8° TYP
.008 – .010
(0.203 0.254)
SO8 0303
.053 – .069
(1.346 1.752)
.014 – .019
(0.355 – 0.483)
TYP
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
1234
.150 – .157
(3.810 – 3.988)
NOTE 3
8765
.189 – .197
(4.801 – 5.004)
NOTE 3
.228 – .244
(5.791 – 6.197)
.245
MIN .160 ±.005
RECOMMENDED SOLDER PAD LAYOUT
.045 ±.005
.050 BSC
.030 ±.005
TYP
INCHES
(MILLIMETERS)
NOTE:
1. DIMENSIONS IN
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
LTC6240/ LTC6241 /LTC6242 L7 LJUW
LTC6240/LTC6241/LTC6242
31
624012fe
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
REVISION HISTORY
REV DATE DESCRIPTION PAGE NUMBER
E 07/10 Update to Simplifi ed Schematic (Figure 1) 19
(Revision history begins at Rev E)
LTCb240/LTCé241 / LTC6242 L7Hfl§fl§
LTC6240/LTC6241/LTC6242
32
624012fe
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2005
LT 0710 REV E • PRINTED IN USA
PART NUMBER DESCRIPTION COMMENTS
LTC1151 ±15V Zero-Drift Op Amp Dual High Voltage Operation ±18V
LT1792 Low Noise Precision JFET Op Amp 6nV/√Hz Noise, ±15V Operation
LTC2050 Zero-Drift Op Amp 2.7 Volt Operation, SOT-23
LTC2051/LTC2052 Dual/Quad Zero-Drift Op Amp Dual/Quad Version of LTC2050 in MS8/GN16 Packages
LTC2054/LTC2055 Single/Dual Zero-Drift Op Amp Micropower Version of the LTC2050/LTC2051 in SOT-23 and DD Packages
LTC6244 Dual 50MHz Rail-to-Rail Op Amp 100µV VOS(MAX), 1pA IBIAS, 40V/µV, Slew Rate
Figure 15. Ultralow Noise 1MΩ 150kHz Photodiode Amplifi er
LTC6241 Output Noise Spectrum. 1MΩ Resistor Noise
Dominates; Ideal Performance Competition Output Noise Spectrum. Op Amp Noise Dominates;
Performance Compromised
RELATED PARTS
TYPICAL APPLICATION
R2
1.69k
C3
180pF
C1
1500pF
+1.5V
–1.5V
–1.5V
SFH213FA
OR EQUIVALENT
(≤4pF) 6241 TA02a
RF
1M
R1
866Ω
+1/2
LTC6241
+1/2
LTC6241
C2
1500pF
CF
1pF
1MΩ TIA 150kHz 3RD ORDER BUTTERWORTH FILTER
R3
2k
1kHz 101kHz10kHz/DIV
6241 TA02b
0V
30nV/√Hz PER DIV
1kHz 101kHz
6241 TA02c
10kHz/DIV
0V
30nV/√Hz PER DIV

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