AD8010 Datasheet by Analog Devices Inc.

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REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
a
AD8010
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 2000
200 mA Output Current
High-Speed Amplifier
CONNECTION DIAGRAMS
8-Lead DIP and SOIC
8
7
6
5
1
2
3
4
NC = NO CONNECT
NC
–IN
+IN
NC
+VS
OUT
NC–VS
AD8010
16-Lead Wide Body SOIC
16
15
14
13
1
2
3
4
NC = NO CONNECT
NC
IN
+IN
NC
+V
S
OUT
NC
V
S
12
11
10
9
5
6
7
8
NC
NC
NC
NC
NC
NC
NC
NC
AD8010
V
IN
+5V
5V
75V
OUT1
V
OUT2
V
OUT3
V
OUT4
V
OUT5
V
OUT6
V
OUT7
V
OUT8
75
AD8010
R
T
R
G
R
F
R
S
Figure 1. Video Distribution Amplifier
PRODUCT DESCRIPTION
The AD8010 is a low power, high current amplifier capable of
delivering a minimum load drive of 175 mA. Signal performance
such as 0.02% and 0.03° differential gain and phase error is
maintained while driving eight 75 back terminated video lines.
The current feedback amplifier features gain flatness to 60 MHz
and –3 dB (G = +1) signal bandwidth of 230 MHz and only
requires a typical of 15.5 mA supply current from ±5 V supplies.
These features make the AD8010 an ideal component for Video
Distribution Amplifiers or as the drive amplifier within high data
rate Digital Subscriber Line (VDSL and xDSL) systems.
The AD8010 is an ideal component choice for any application
that needs a driver that will maintain signal quality when driving
low impedance loads.
The AD8010 is offered in three package options: an 8-lead DIP,
16-lead wide body SOIC and a low thermal resistance 8-lead
SOIC, and operates over the industrial temperature range of
–40°C to +85°C.
FEATURES
200 mA of Output Current
9 Load
SFDR –54 dBc @ 1 MHz
Differential Gain Error 0.04%, f = 4.43 MHz
Differential Phase Error 0.06, f = 4.43 MHz
Maintains Video Specifications Driving Eight Parallel
75 Loads
0.02% Differential Gain
0.03 Differential Phase
0.1 dB Gain Flatness to 60 MHz
THD –72 dBc @ 1 MHz, RL = 18.75
IP3 42 dBm @ 5 MHz, RL = 18.75
1 dB Gain Compression 21 dBm @ 5 MHz, RL = 100
230 MHz –3 dB Bandwidth, G = +1, RL = 18.75
800 V/s Slew Rate, RL = 18.75
25 ns Settling Time to 0.1%
Available in 8-Lead DIP, 16-Lead Wide Body SOIC and
Thermally Enhanced 8-Lead SOIC
APPLICATIONS
Video Distribution Amplifier
VDSL, xDSL Line Driver
Communications
ATE
Instrumentation
–2– REV. B
AD8010–SPECIFICATIONS
(@ 25C, VS = 5 V, G = +2, RL = 18.75 , RS+ = 150 , RF = RG = 604 (R-16),
RF = RG = 562 (N-8), RF = RG = 499 (R-8). TMIN = –40C, TMAX = +85C unless otherwise noted)
M
odel Conditions Min Typ Max Unit
DYNAMIC PERFORMANCE
–3 dB Bandwidth G = +1, V
OUT
= 0.2 V p-p 180 230 MHz
G = +2, V
OUT
= 0.2 V p-p 130 190 MHz
0.1 dB Bandwidth V
OUT
= 0.2 V p-p 30 60 MHz
Large Signal Bandwidth V
OUT
= 4 V p-p 90 MHz
Peaking V
OUT
= 0.2 V p-p, < 5 MHz 0.02 dB
Slew V
OUT
= 2 V p-p 800 V/µs
Rise and Fall Time V
OUT
= 2 V p-p 2.0 ns
Settling Time 0.1%, V
OUT
= 2 V p-p 25 ns
NOISE/HARMONIC PERFORMANCE
Distortion V
OUT
= 2 V p-p
2nd Harmonic 1 MHz –73 dBc
5 MHz –58 dBc
10 MHz –53 dBc
10 MHz, R
L
= 39 –67 dBc
20 MHz –44 dBc
3rd Harmonic 1 MHz –77 dBc
5 MHz –63 dBc
10 MHz –57 dBc
10 MHz, R
L
= 39 –63 dBc
20 MHz –50 dBc
IMD 5 MHz f = 10 kHz –73 dBc
IP3 5 MHz 42 dBm
1 dB Gain Compression 5 MHz 21 dBm
Input Noise Voltage f = 10 kHz 2 nVHz
Input Noise Current f = 10 kHz, +In 3 pAHz
f = 20 kHz, –In 20 pAHz
Differential Gain f = 4.43 MHz, R
L
= 150 0.02 %
f = 4.43 MHz, R
L
= 18.75 0.02 %
Differential Phase f = 4.43 MHz, R
L
= 150 0.02 Degrees
f = 4.43 MHz, R
L
=18.75 0.03 Degrees
DC PERFORMANCE
Input Offset Voltage 512mV
T
MIN
–T
MAX
15 mV
Offset Drift 10 µV/°C
Input Bias Current (–) 10 135 µA
T
MIN
–T
MAX
200 µA
Input Bias Current (+) 612µA
T
MIN
–T
MAX
20 µA
INPUT CHARACTERISTICS
Input Resistance +Input 125 k
–Input 12.5
Input Capacitance 2.75 pF
Common-Mode Rejection Ratio V
CM
= ±2.5 V 50 54 dB
Input Common-Mode Voltage Range ±2.5 V
Open Loop Transresistance V
OUT
= ±2.5 V 300 500 k
T
MIN
–T
MAX
250 k
OUTPUT CHARACTERISTICS
Output Voltage Swing
R
L
= 18.75 Ω ±2.1 ±2.5 V
R
L
= 150 Ω ±2.7 ±3.0 V
Output Current R
L
= 9 175 200 mA
Short-Circuit Current 240 mA
Capacitive Load Drive 40 pF
POWER SUPPLY
Operating Range ±4.5 ±6.0 V
Quiescent Current 15.5 17 mA
T
MIN
to T
MAX
20 mA
Power Supply Rejection Ratio +V
S
= +4 V to +6 V, –V
S
= +5 V 60 66 dB
+V
S
= +5 V, –V
S
= –4 V to –6 V 50 56 dB
Specifications subject to change without notice.
\x\
AD8010
–3–REV. B
ABSOLUTE MAXIMUM RATINGS
1
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.6 V
Internal Power Dissipation
2
Plastic Package (N) . . . . . . Observe Power Derating Curves
Small Outline Package (R) . Observe Power Derating Curves
Wide Body SOIC (R-16) . . . Observe Power Derating Curves
Input Voltage (Common-Mode) . . . . . . . . . . . . . . . . . . . ±V
S
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . ±1.2 V
Output Short Circuit Duration
. . . . . . . . . . . . . . . . . . . . . . Observe Power Derating Curves
Storage Temperature Range N, R . . . . . . . . –65°C to +125°C
Operating Temperature Range (A Grade) . . –40°C to +85°C
Lead Temperature Range (Soldering 10 sec) . . . . . . . . 300°C
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
2
Specification is for device in free air:
8-Lead Plastic Package: θ
JA
= 90°C/W
8-Lead SOIC Package: θ
JA
= 122°C/W
16-Lead SOIC Package: θ
JA
= 73°C/W
AMBIENT TEMPERATURE C
3.0
2.5
0
50
MAXIMUM POWER DISSIPATION Watts
2.0
1.5
1.0
0.5
40 30 20 10 0 10 203040 5060708090
8-LEAD SOIC PACKAGE
8-LEAD MINI-DIP PACKAGE
16-LEAD SOIC
PACKAGE (WIDEBODY)
T
J
= 150C
Figure 2. Plot of Maximum Power Dissipation vs. Temperature
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD8010 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
WARNING!
ESD SENSITIVE DEVICE
ORDERING GUIDE
Model Temperature Range Package Description Package Options
AD8010AN –40°C to +85°C 8-Lead Plastic DIP N-8
AD8010AR –40°C to +85°C 8-Lead Plastic SOIC SO-8
AD8010AR-16 –40°C to +85°C 16-Lead Wide Body SOIC R-16
AD8010AR-REEL REEL SOIC 13" REEL
AD8010AR-REEL7 REEL SOIC 7" REEL
AD8010AR-16-REEL REEL SOIC 13" REEL
AD8010AR-16-REEL7 REEL SOIC 7" REEL
MAXIMUM POWER DISSIPATION
The maximum power that can be safely dissipated by the
AD8010 is limited by the associated rise in junction temperature.
The maximum safe junction temperature for plastic encapsu-
lated devices is determined by the glass transition temperature
of the plastic, approximately +150°C. Temporarily exceeding
this limit may cause a shift in parametric performance due to a
change in the stresses exerted on the die by the package. Exceed-
ing a junction temperature of +175°C for an extended period
can result in device failure.
While the AD8010 is internally short circuit protected, this
may not be sufficient to guarantee that the maximum junction
temperature (+150°C) is not exceeded under all conditions. To
ensure proper operation, it is necessary to observe the maximum
power derating curves.
HM «31%deer NUMBER or when LOADS FREouEch 7 MHz snn
AD8010
–4– REV. B
dG
(
%
)
/d
De
g
rees
60
30
0
0.130.01
PERCENTAGE OF UNITS
0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12
50
40
20
10
d
G = +2
f = 4.43MHz (PAL)
R
L
= 18.75
0
SAMPLE SIZE = 300
dG
dG
dG
dG
d
d
ddddddd
d
DIFFERENTIAL GAIN dG IN %
DIFFERENTIAL PHASE d IN Degrees
Figure 3. Distribution of Differential Gain (dG) and
Differential Phase (d
φ
); R
L
= 18.75
FREQUENCY MHz
G = +2
V
O
= 2V p-p
R
L
AS SHOWN
45
50
55
60
65
70
75
80
85
90
95
12 56789102034
2ND
R
L
= 18.753RD
R
L
= 1002ND
3RD
HARMONIC DISTORTION dBc
Figure 4. Harmonic Distortion vs. Frequency; G = +2
G = +2
RL = 18.75
VO = 0.2V p-p
FREQUENCY MHz
0.1 1
GAIN FLATNESS dB
10 100
6.20
6.15
6.10
6.05
6.0
5.95
5.90
5.85
5.80
500
+85C
+25C
40C
Figure 5. Gain Flatness vs. Frequency Over Temperature
(–40
°
C to +85
°
C)
NUMBER OF VIDEO LOADS
0.05
0.04
DIFFERENTIAL PHASE
0162 4 6 8 10 12 14
0.03
0.02
0.01
DIFFERENTIAL GAIN %
1
0.10
0.08
0
0.06
0.04
0.02
DIFFERENTIAL PHASE Degrees
DIFFERENTIAL GAIN
Figure 6. Differential Gain and Phase vs. Number of Video
Loads Over Temperature (–40
°
C to +85
°
C); f = 4.43 MHz
FREQUENCY MHz
45
40
5
1 10010
INTERCEPT POINT dBm
35
30
10
25
20
15
G = +2
R
L
= 18.75
Figure 7. Two-Tone, 3rd Order IMD Intercept vs.
Frequency; G = +2, R
L
= 18.75
6.5
6.4
6.3
6.2
6.1
6.0
5.9
5.8
5.7
5.6
5.5
1
FREQUENCY MHz
G = +2
V
O
= 0.2V p-p
NUMBER OF VIDEO
LOADS AS SHOWN
4
6
8
10
14
12
1
10 100 1000
2
GAIN FLATNESS dB
Figure 8. Gain Flatness vs. Frequency vs. Number of
Video Loads
Typical Performance Characteristics
FREQUENCV’MHI son 15m) / . P R RU:2C|.1FOR RL:1B,7511 FREQUENCV’MHI
AD8010
–5–REV. B
5.0355.0155.04.9854.965
FREQUENCY MHz
INTERMODULATION DISTORTION dBm
5
5
15
25
35
45
55
65
75
85
G = +2
R
L
= 18.75
f
O
= 5MHz
f
= 10kHz
4dBm
4dBm
P
OUT
69dBm 69dBm
Figure 9. Intermodulation Distortion
P
OUT
dBm
35
75
105
10 128
TOTAL HARMONIC DISTORTION dBc
6420 246810
45
55
85
95
65
FREQUENCY = 5MHz
G = +2
R
L
= AS SHOWN (SEE SCHEMATIC)
R
L1
= FOR R
L
= 100
R
L1
= 23.1 FOR R
L
= 18.75
50
50
P
OUT
P
IN
R
F
R
G
150
50
R
L1
R
L
= 100
R
L
= 18.75
Figure 10. Total Harmonic Distortion vs. P
OUT
; G = +2
FREQUENCY MHz
2
1
7
0.1 10001
NORMALIZED GAIN dB
10 100
0
1
6
2
3
4
5
GAIN AS SHOWN
V
O
= 0.2V p-p
R
L
= 18.75
G = +1
G = +2
G = +3
Figure 11. Small Signal Closed-Loop Frequency
Response; R
L
= 18.75
Figure 12. Multitone Distortion; R
L
= 100
G = +2
V
O
= 2V p-p
f = 5MHz
LOAD
55
60
65
70
75
80
85
90
15 100 200 300 400 500
2
ND
3
RD
HARMONIC DISTORTION dBc
Figure 13. Harmonic Distortion vs. Load
Figure 14. Closed-Loop Frequency Response vs.
Number of Video Loads
man‘mmsa
AD8010
–6– REV. B
FREQUENCY MHz
10
20
0.03 500
0.1
PSRR dB
1 10 100
30
40
80
50
60
70
+PSRR
PSRR
Figure 15. PSRR vs. Frequency
FREQUENCY MHz
0.1 500
1
CLOSED-LOOP OUTPUT RESISTANCE
10 100
310
100
31
10
3.1
1
0.31
0.1
0.031
G = +2
Figure 16. Closed-Loop Output Resistance vs. Frequency
FREQUENCY MHz
2
1
0.1 10001
NORMALIZED GAIN dB
10 100
1
2
7
3
4
5
6
0
GAIN AS SHOWN
V
O
= 2V p-p
R
L
= 18.75
G = +1
G = +10
G = +2
Figure 17. Large Signal Frequency Response; V
O
= 2 V p-p
FREQUENCY MHz
0.1 5001
CMRR dB
10 100
0
10
100
20
30
40
50
60
70
80
90
Figure 18. CMRR vs. Frequency
FREQUENCY Hz
316
0.31610k 1G100k
TRANSRESISTANCE k
1M 10M 100M
100
31.6
10
3.16
1
90
135
180
PHASE De
g
rees
225
45
0
TRANSRESISTANCE
1000
PHASE
Figure 19. Transresistance and Phase vs. Frequency;
R
L
= 18.75
FREQUENCY MHz
0.1 1000
0
NORMALIZED GAIN dB
10 100
3.0
2.0
7.0
1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
GAIN AS SHOWN
VO = 4V p-p
RL = 18.75
G = +10
G = +2
Figure 20. Large Signal Frequency Response; V
O
= 4 V p-p
INPUT vonAGE NOISE - th/tT rnzouzucv 7 Hz
AD8010
–7–REV. B
0.05
0.2
0
0.1
0.2
0.1
0.05
0.15
0.15
VOLTS
G = +1
R
L
= 18.75
V
O
= 0.2V p-p
50mV 20ns
Figure 21. Small-Signal Pulse Response; G = +1
0.05
0.2
0
0.1
0.2
0.1
0.05
0.15
0.15
50mV 20ns
G = +2, 1
RL = 18.75
VO = 0.2V p-p
VOLTS
Figure 22. Small-Signal Pulse Response; G = +2, –1
100
10
FREQUENCY Hz
1k
10 100 10k 100k 1M
1
INPUT VOLTAGE NOISE nV/ Hz
10M
Figure 23. Input Voltage Noise vs. Frequency
1V 20ns
G = +1
RL = 18.75
VO = 4V p-p
VOLTS
5
4
3
2
1
0
1
2
3
4
5
Figure 24. Large-Signal Pulse Response; G = +1
1V 20ns
G = +2, 1
R
L
= 18.75
V
O
= 4V p-p
4
3
2
1
0
1
2
3
4
VOLTS
Figure 25. Large-Signal Pulse Response; G = +2, –1
INVERTING CURRENT
NONINVERTING CURRENT
100
10
1
10 100 1k 10k 100k 1M
FREQUENCY Hz
INPUT CURRENT NOISE pA/ Hz
1000
10M
Figure 26. Input Current Noise vs. Frequency
AD8010
–8– REV. B
0
VOLTS
INPUT (500mV/DIV)
OUTPUT (1V/DIV)
G = +6
R
F
= 604
R
L
= 18.75
INPUT OUTPUT
100ns
Figure 27. Overdrive Recovery; G = +6
OVERDRIVE RECOVERY
Overdrive of an amplifier occurs when the output and/or input
range are exceeded. The amplifier must recover from this over-
drive condition. As shown in Figure 27, the AD8010 recovers
within 35 ns from negative overdrive and within 75 ns from
positive overdrive.
THEORY OF OPERATION
The AD8010 is a current feedback amplifier optimized for high
current output while maintaining excellent performance with
respect to flatness, distortion and differential gain/phase. As a
video distribution amplifier, the AD8010 will drive up to 12
parallel video loads (12.5 ) from a single output with 0.04%
differential gain and 0.04° differential phase errors. This means
that, unlike designs with one driver per output, any output is a
true reflection of the signal on all other outputs.
The high output current capability of the AD8010 also make it
useful in xDSL applications. The AD8010 can drive a 12.5
single-ended or 25 differential load with low harmonic dis-
tortion. This makes it useful in designs that utilize a step-up
transformer to drive a twisted-pair transmission line.
To achieve these levels of performance special precautions with
respect to supply bypassing are recommended (Figure 29). This
configuration minimizes the contribution from high frequency
supply rejection to differential gain and phase errors as well as
reducing distortion due to harmonic energy in the power supplies.
R
S
200
100
10205
CAPACITIVE LOAD pF
10
10 15
G = +2
G = +5
G = +1
GAIN AS SHOWN
V
O
= 0.2V p-p
w/ 30% OVERSHOOT
V
OUT
V
IN
R
F
R
G
150
50
R
S
C
L
Figure 28. Capacitive Load Drive vs. Series Resistor for
Various Gains
Driving Capacitance Loads
The AD8010 was designed primarily to drive nonreactive loads.
If driving loads with a capacitive component is desired, best
frequency response is obtained by the addition of a small series
resistance as shown in Figure 28. The inset figure shows the
optimum value for R
SERIES
vs. capacitive load. It is worth noting
that the frequency response of the circuit when driving large
capacitive loads will be dominated by the passive roll-off of
R
SERIES
and C
L
.
LAYOUT CONSIDERATIONS
The specified high speed performance of the AD8010 requires
careful attention to board layout and component selection.
Proper R
F
design techniques and low-pass parasitic component
selection are necessary.
The PCB should have a ground plane covering all unused portions
of the component side of the board to provide low impedance
path. The ground plane should be removed from the area near
the input pins to reduce the parasitic capacitance.
AD8010
V
IN
150
R
F
R
G
R
T
+V
S
V
S
FB
C1
+
R
BT
Z
O
R
L
C2
+
Figure 29. Standard Noninverting Closed-Loop Configura-
tion with Recommended Bypassing Technique
The standard noninverting closed-loop configuration with the
recommended power supply bypassing technique is shown in
Figure 29. Ferrite beads (Amidon Associates, Torrance CA,
Part Number 43101) are used to suppress high frequency power
supply energy on the DUT supply lines at the DUT. C1 and C2
each represent the parallel combination of a 47 µF (16 V) tanta-
lum electrolytic capacitor, a 10 µF (10 V) tantalum electrolytic
capacitor and a 0.1 µF ceramic chip capacitor. Connect C1
from the +V
S
pin to the –V
S
pin. Connect C2 from the –V
S
pin
to signal ground.
The feedback resistor should be located close to the inverting
input pin in order to keep the parasitic capacitance at this node
to a minimum. Parasitic capacitances of less than 1 pF at the
inverting input can significantly affect high speed performance.
Stripline design techniques should be used for long traces
(greater than about 3 cm). These should be designed with a
characteristic impedance (Z
O
) of 50 or 75 and be properly
terminated at each end.
AD8010
–9–REV. B
APPLICATIONS
Video Distribution Amplifier
The AD8010 is optimized for the specific function of providing
excellent video performance when driving multiple video loads
in parallel. Significant power is saved and heat sinking is greatly
simplified because of the ability of the AD8010 to obtain this
performance when running on a ±5 V supply. However, due to
the high currents that flow when driving many parallel video
loads, special layout and bypassing techniques are required to
assure optimal performance.
When designing a video distribution amplifier with the AD8010, it
is very important to keep in mind where the high (ac) currents
will flow. These paths include the power supply pins of the chip
along with the bypass capacitors and the return path for these
capacitors, the output circuits and the return path of the output
current from the loads.
In general, any loops that are formed by any of the above paths
should be made as small as possible. Large loops are both gen-
erators and receivers of magnetic fields and can cause undesired
coupling of signals that lowers the performance of the amplifier.
Effects that have not been seen before in other op amp circuits
might arise because of the high currents. Most op amp circuits
output, at most, tens of milliamps and do not require extremely
tight video specifications, while a video distribution amplifier
can output hundreds of milliamps and require extremely low
differential gain and phase errors.
The bypassing scheme that is used for the AD8010 requires
special attention. It was found that the conventional technique
of bypassing each power pin individually to ground can have an
adverse effect on the differential phase error of the circuit. The
cause of this is attributed to the fact that there is an internal
compensation capacitor in the AD8010 that is referenced to the
negative supply.
The recommended technique is to connect parallel bypass
capacitors from the positive supply to the negative supply and
then to bypass the negative supply to ground. For high fre-
quency bypassing, 0.1 µF ceramic capacitors are recommended.
These should be placed within a few millimeters of the power
pins and should preferably be chip type capacitors.
The high currents that can potentially flow through the power
supply pins require large bypassing capacitors. These should be
low inductance tantalum types and at least 47 µF. The ground
side of the capacitor that bypasses the negative supply should be
brought to a single point ground that is the common for the
returns of the outputs.
Figure 30 shows a circuit for making an N-channel video distri-
bution amplifier. As a practical matter, the AD8010 can readily
drive eight standard 150 video loads. When driving up to 12
video loads, there is minimal degradation in video performance.
Another important consideration when driving multiple cables
is the high frequency isolation between the outputs of the
cables. Due to its low output impedance, the AD8010 achieves
better than 46 dB of output-to-output isolation at 5 MHz driv-
ing back terminated 75 cables.
AD8010
V
IN
150
75
R
L1
499499
+5V
5V
75
75
75
75
75R
L2
75R
LN
FB
FB
C1
C2
Figure 30. An N-Channel Video Distribution Amplifier Using An AD8010.
NOTE: Please see Figure 29 for Recommended Bypassing Technique.
mm H Isou mm mm Isou 12M:
AD8010
–10– REV. B
Differential Line Driver
Twisted pair transmission lines are more often being used for
high frequency analog and digital signals. Over long distances,
however, the attenuation characteristics of these lines can
degrade the performance of the transmission system. To com-
pensate for this, larger signals are transmitted, which after the
attenuation, will still have useful signal strength.
The high output current of two AD8010s can be used along
with a transformer to create a high power differential line driver.
The differential configuration effectively doubles the output
swing, while the step-up transformer further increases the out-
put voltage.
In the circuit in Figure 31 the A device is configured as a gain-
of-two follower, while the B device is a gain-of-two inverter.
These will produce a differential output signal whose maximum
value is twice the peak-to-peak value of the maximum output
of one device. For this circuit a 12 V peak-to-peak output can
be obtained.
The op amps drive a 1:2 step-up transformer that drives a
100 transmission line. Since the impedance reflected back to
the primary varies as the square of the turns ratio, it will appear
as 25 at the primary. This source terminating resistor is split
as a 12.4 resistor at the output of each device.
The circuit shown is capable of delivering 12 V p-p to the line
and operates with a –3 dB bandwidth of 40 MHz. The peak
current output of either op amp is 100 mA.
AD8010
V
IN
499
499
150
402
AD8010
150
806
12.4
12.4+6
6
1:2
100
Figure 31. High Output Differential Line Driver Using Two AD8010s.
NOTE: Please see Figure 29 for Recommended Bypassing Technique.
AD8010
–11–REV. B
Table I. –3 dB Bandwidth and Slew Rate vs. Closed-Loop
Gain and Resistor Values
Package: N-8
Closed-Loop –3 dB BW Slew Rate
Gain R
F
()R
G
() (MHz) (V/s)
+1 453
285 900
+2 374 374 255 900
+5 348 86.6 200 800
+10 562 61.9 120 550
Package: R-16
Closed-Loop –3 dB BW Slew Rate
Gain R
F
()R
G
() (MHz) (V/s)
+1 412
245 900
+2 392 392 220 900
+5 392 97.6 160 800
+10 604 66.5 95 550
Package: SO-8
Closed-Loop –3 dB BW Slew Rate
Gain R
F
()R
G
() (MHz) (V/s)
+1 392
345 950
+2 374 374 305 1000
+5 348 86.6 220 1000
+10 499 54.9 135 650
1. V
O
= 0.2 V p-p for –3 dB Bandwidth.
2. V
O
= 2 V p-p for Slew Rate.
3. Bypassing per Figure 29.
150
50
R
F
R
G
V
OUT
18.75
V
IN
Figure 32. Test Circuit for Table I
Closed-Loop Gain and Bandwidth
The AD8010 is a current feedback amplifier optimized for use
in high performance video and data acquisition applications.
Since it uses a current feedback architecture, its closed-loop
–3 dB bandwidth is dependent on the magnitude of the feedback
resistor. The desired closed-loop bandwidth and gain are obtained
by varying the feedback resistor (R
F
) to set the bandwidth, and
varying the gain resistor (R
G
) to set the desired gain. The char-
acteristic curves and specifications for this data sheet reflect the
performance of the AD8010 using the values of R
F
noted at the
top of the specifications table. If a greater –3 dB bandwidth
and/or slew rate is required (at the expense of video performance),
Table I provides the recommended resistor values. Figure 32
shows the test circuit and conditions used to produce Table I.
Effect of Feedback Resistor Tolerance on Gain Flatness
Because of the relationship between the 3 dB bandwidth and the
feedback resistor, the fine scale gain flatness will, to some extent,
vary with feedback resistor tolerance. It is therefore recommended
that resistors with a 1% tolerance be used if it is desired to main-
tain flatness over a wide range of production lots. In addition,
resistors of different construction have different associated para-
sitic capacitance and inductance. Metal-film resistors were used
for the bulk of the characterization for this data sheet. It is pos-
sible that values other than those indicated will be optimal for
other resistor types.
Quality of Coaxial Cable
Optimum flatness when driving a coax cable is possible only
when the driven cable is terminated at each end with a resistor
matching its characteristic impedance. If the coax was ideal,
then the resulting flatness would not be affected by the length of
the cable. While outstanding results can be achieved using inex-
pensive cables, it should be noted that some variation in flatness
due to varying cable lengths may be experienced.
+ r T J (41% wii 491$ ' féuuuil 7 W ’H‘7 L i WHHH TL, Ah fifififififififi' T T HRHHHHHHH
–12– REV. B
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
C01047a–0–12/00 (rev. B)
PRINTED IN U.S.A.
AD8010
8-Lead Plastic Mini-DIP
(N-8)
8
14
5
0.430 (10.92)
0.348 (8.84)
0.280 (7.11)
0.240 (6.10)
PIN 1
SEATING
PLANE
0.022 (0.558)
0.014 (0.356)
0.060 (1.52)
0.015 (0.38)
0.210 (5.33)
MAX 0.130
(3.30)
MIN
0.070 (1.77)
0.045 (1.15)
0.100
(2.54)
BSC
0.160 (4.06)
0.115 (2.93)
0.325 (8.25)
0.300 (7.62)
0.015 (0.381)
0.008 (0.204)
0.195 (4.95)
0.115 (2.93)
8-Lead SOIC
(SO-8)
0.1968 (5.00)
0.1890 (4.80)
85
41
0.2440 (6.20)
0.2284 (5.80)
PIN 1
0.1574 (4.00)
0.1497 (3.80)
0.0688 (1.75)
0.0532 (1.35)
SEATING
PLANE
0.0098 (0.25)
0.0040 (0.10)
0.0192 (0.49)
0.0138 (0.35)
0.0500
(1.27)
BSC
0.0098 (0.25)
0.0075 (0.19)
0.0500 (1.27)
0.0160 (0.41)
8
0
0.0196 (0.50)
0.0099 (0.25) 45
16-Lead Wide Body SOIC
(R-16)
16 9
81
0.4133 (10.50)
0.3977 (10.00)
0.4193 (10.65)
0.3937 (10.00)
0.2992 (7.60)
0.2914 (7.40)
PIN 1
SEATING
PLANE
0.0118 (0.30)
0.0040 (0.10)
0.0192 (0.49)
0.0138 (0.35)
0.1043 (2.65)
0.0926 (2.35)
0.0500
(1.27)
BSC
0.0125 (0.32)
0.0091 (0.23)
0.0500 (1.27)
0.0157 (0.40)
8
0
0.0291 (0.74)
0.0098 (0.25) 45

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