BCM8Bx120x300A00 Datasheet by Vicor Corporation

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VICOR iv?»— 9% cflus@lc € l—V—V VICOR’
BCM® Bus Converter
Isolated Fixed Ratio DC-DC Converter
BCM® Bus Converter Rev 1.9
Page 1 of 21 01/2021
S
NRTL
CUS
CUS
®
BCM48Bx120y300A00
SW1
enable / disable
switch
F1
VIN
PC
TM
-OUT
+OUT
-IN
+IN
L
O
A
D
BCM®
Bus Converter
Features & Benefits
48VDC – 12VDC 300W Bus Converter
High efficiency (>96%) reduces system
power consumption
High power density (>1022W/in3)
reduces power system footprint by >40%
Contains built-in protection features:
Undervoltage
Overvoltage Lockout
Overcurrent Protection
Short circuit Protection
Overtemperature Protection
Provides enable/disable control,
internal temperature monitoring
Can be paralleled to create multi-kW arrays
Typical Applications
High-End Computing Systems
Automated Test Equipment
High-Density Power Supplies
Communications Systems
Description
The VI Chip® bus converter is a high efficiency (>96%) Sine
Amplitude Converter™ (SAC™) operating from a 38 to 55VDC
primary bus to deliver an isolated, ratiometric output voltage from
9.5 to 13.8VDC. The Sine Amplitude Converter offers a low AC
impedance beyond the bandwidth of most downstream regulators;
therefore capacitance normally at the load can be located at the
input to the Sine Amplitude Converter. Since the transformation
ratio of the BCM48Bx120y300A00 is 1/4, the capacitance value can
be reduced by a factor of 16x, resulting in savings of board area,
materials and total system cost.
The BCM48BF120y300A00 is provided in a VI Chip package
compatible with standard pick-and-place and surface mount
assembly processes. The co-molded VI Chip package provides
enhanced thermal management due to a large thermal interface
area and superior thermal conductivity. The high conversion
efficiency of the BCM48Bx120y300A00 increases overall
system efficiency and lowers operating costs compared to
conventional approaches.
Typical Application
Product Number Package Style (x) Product Grade (y)
BCM48Bx120y300A00 F = J-Lead T = –40 to 125°C
T = Through hole M = –55 to 125°C
Product Ratings
VIN = 48V (38 – 55V) POUT= up to 300W
VOUT = 12V (9.5 – 13.8V)
(no load)K = 1/4
For Storage and Operating Temperatures see General Characteristics
Part Numbering
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BCM® Bus Converter Rev 1.9
Page 2 of 21 01/2021
BCM48Bx120y300A00
–IN
PC
RSV
TM
+IN
–OUT
+OUT
–OUT
+OUT
Bottom View
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
T
43 21
A
B
C
D
E
H
J
K
L
M
N
P
R
T
Pin Configuration
Pin Descriptions
Pin Number Signal Name Type Function
A1-E1, A2-E2 +IN INPUT POWER Positive input power terminal
L1-T1, L2-T2 –IN INPUT POWER
RETURN Negative input power terminal
H1, H2 TM OUTPUT Temperature monitor, input side referenced signal
J1, J2 RSV NC No connect
K1, K2 PC OUTPUT/INPUT Enable and disable control, input side referenced signal
A3-D3, A4-D4,
J3-M3, J4-M4 +OUT OUTPUT POWER Positive output power terminal
E3-H3, E4-H4,
N3-T3, N4-T4 –OUT OUTPUT POWER
RETURN Negative output power terminal
VICOR
BCM® Bus Converter Rev 1.9
Page 3 of 21 01/2021
BCM48Bx120y300A00
Absolute Maximum Ratings
The absolute maximum ratings below are stress ratings only. Operation at or beyond these maximum ratings can cause permanent damage to the device.
Parameter Comments Min Max Unit
+IN to –IN –1 60 V
VIN Slew Rate Operational –1 1 V/µs
Isolation Voltage, Input to Ouput 2250 V
+OUT to –OUT –1 16 V
Output Current Transient ≤ 10ms, ≤ 10% DC –3 37.5 A
Output Current Average –2 30 A
PC to –IN –0.3 20 V
TM to –IN –0.3 7 V
VICOR
BCM® Bus Converter Rev 1.9
Page 4 of 21 01/2021
BCM48Bx120y300A00
Electrical Specifications
Specifications apply over all line and load conditions, unless otherwise noted; boldface specifications apply over the temperature range of
–40°C ≤ TCASE ≤ 100°C (T-Grade); all other specifications are at TCASE = 25°C unless otherwise noted.
Attribute Symbol Conditions / Notes Min Typ Max Unit
Powertrain
Input Voltage Range, Continuous VIN_DC 38 55 V
Input Voltage Range, Transient VIN_TRANS Full current or power supported, 50ms max,
10% duty cycle max 38 55 V
Quiescent Current IQDisabled, PC Low 0.5 1.0 mA
VIN to VOUT Time tON1 VIN = 48V, PC floating 340 450 620 ms
No-Load Power Dissipation PNL
VIN = 48V, TCASE = 25°C 5.3 6.5
W
VIN = 48V 3 15
VIN = 38 – 55V, TCASE = 25°C 9
VIN = 38 – 55V 17
Inrush Current Peak IINR_P Worse case of: VIN = 55V, COUT = 1000μF,
RLOAD = 391mΩ 10 20 A
DC Input Current IIN_DC At POUT = 300W 8.8 A
Transformation Ratio K K = VOUT / VIN, at no load 1/4 V/V
Output Power (Average) POUT_AVG 300 W
Output Power (Peak) POUT_PK 10ms max, POUT_AVG ≤ 300W 450 W
Output Current (Average) IOUT_AVG 30 A
Output Current (Peak) IOUT_PK 10ms max, IOUT_AVG ≤ 30A 37.5 A
Efficiency (Ambient) ηAMB
VIN = 48V, IOUT = 25A; TCASE = 25°C 95.0 96.0
%VIN = 38 – 55V, IOUT = 25A; TCASE = 25°C 93.5
VIN = 48V, IOUT = 12.5A; TCASE = 25°C 94.5 95.5
Efficiency (Hot) ηHOT VIN = 48V, IOUT = 25A; TCASE = 100°C 94.5 95.6 %
Efficiency (Over Load Range) η20% 5A < IOUT < 25A 80 %
Output Resistance
ROUT_COLD IOUT = 25A, TCASE = –40°C 4.9 6.7 12.0
ROUT_AMB IOUT = 25A, TCASE = 25°C 6.3 9.0 14.0
ROUT_HOT IOUT = 25A, TCASE = 100°C 8.8 11.5 16.0
Switching Frequency FSW 1.85 1.95 2.05 MHz
Output Voltage Ripple VOUT_PP COUT = 0F, IOUT = 25A, VIN = 48V,
20MHz BW 150 285 mV
Output Inductance (Parasitic) LOUT_PAR Frequency up to 30MHz, simulated J-lead model 600 pH
Output Capacitance (Internal) COUT_INT Effective value at 12VOUT 47 µF
Output Capacitance (External) COUT_EXT 0 1000 µF
VICOR
BCM® Bus Converter Rev 1.9
Page 5 of 21 01/2021
BCM48Bx120y300A00
Electrical Specifications (Cont.)
Specifications apply over all line and load conditions, unless otherwise noted; boldface specifications apply over the temperature range of
–40°C ≤ TCASE ≤ 100°C (T-Grade); all other specifications are at TCASE = 25°C unless otherwise noted.
Attribute Symbol Conditions / Notes Min Typ Max Unit
Protection
Input Overvoltage Lockout Threshold VIN_OVLO+ 55.1 58.5 60 V
Input Overvoltage
Recovery Threshold VIN_OVLO– 55.1 58.0 60 V
Input Overvoltage Lockout Hysteresis VIN_OVLO_HYST 1.2 V
Overvoltage Lockout Response Time tOVLO 8 µs
Fault Recovery Time tAUTO_RESTART 240 300 380 ms
Input Undervoltage
Lockout Threshold VIN_UVLO– 28.5 31.1 37.4 V
Input Undervoltage
Recovery Threshold VIN_UVLO+ 28.5 33.7 37.4 V
Input Undervoltage
Lockout Hysteresis VIN_UVLO_HYST 1.6 V
Undervoltage Lockout
Response Time tUVLO 8 µs
Output Overcurrent Trip Threshold IOCP 30 39 55 A
Output Overcurrent Response
Time Constant tOCP Effective internal RC filter 5.3 ms
Short Circuit Protection
Trip Threshold ISCP 30 A
Short Circuit Protection
Response Time tSCP 1 µs
Thermal Shut-Down Threshold TJ_OTP 125 °C
Output Voltage (V)
Output Power (W)
P (ave) P (pk), < 10ms I (ave) I (pk), < 10ms
Output Current (A)
200
225
250
275
300
325
350
375
8.70 9.23 9.76 10.29 10.82 11.3611.89 12.4212.95 13.4814.01
6.25
12.50
18.75
25.00
31.25
37.50
43.75
50.00
Figure 1 Safe operating area
VICOR
BCM® Bus Converter Rev 1.9
Page 6 of 21 01/2021
BCM48Bx120y300A00
Signal Characteristics
Specifications apply over all line and load conditions, unless otherwise noted; boldface specifications apply over the temperature range of
–40°C ≤ TCASE ≤ 100°C (T-Grade); all other specifications are at TCASE = 25°C unless otherwise noted.
Primary Control: PC
The PC pin enables and disables the BCM. When held low, the BCM is disabled.
In an array of BCM modules, PC pins should be interconnected to synchronize start up and permit start up into full load conditions.
PC pin outputs 5V during normal operation. PC pin internal bias level drops to 2.5V during fault mode, provided VIN remains in the valid range.
Signal Type State Attribute Symbol Conditions / Notes Min Typ Max Unit
Analog
Output
Regular
Operation
PC Voltage VPC 4.7 5.0 5.3 V
PC Available Current IPC_OP 2.0 3.5 5.0 mA
Standby PC Source (Current) IPC_EN 50 100 µA
PC Resistance (Internal) RPC_INT Internal pull down resistor 50 150 400
Transition PC Capacitance (Internal) CPC_INT 1000 pF
Start Up PC Load Resistance RPC_S To permit regular operation 60
Digital
Input /
Output
Regular
Operation
PC Enable Threshold VPC_EN 2.0 2.5 3.0 V
PC Disable Threshold VPC_DIS 1.95 V
Standby PC Disable Duration tPC_DIS_T Minimum time before attempting
re-enable 1s
Transition
PC Threshold Hysteresis VPC_HYSTER 50 mV
PC Enable to VOUT Time tON2 VIN = 48V for at least tON1 ms 50 100 150 µs
PC Disable to Standby Time tPC_DIS 410 µs
PC Fault Response Time tFR_PC From fault to PC = 2V 100 µs
Temperature Monitor: TM
The TM pin monitors the internal temperature of the controller IC within an accuracy of ±5°C.
Can be used as a “Power Good” flag to verify that the BCM module is operating.
Is used to drive the internal comparator for Overtemperature Shut Down.
Signal Type State Attribute Symbol Conditions / Notes Min Typ Max Unit
Analog
Output
Regular
Operation
TM Voltage Range VTM 2.12 4.04 V
TM Voltage Reference VTM_AMB TJ controller = 27°C 2.95 3.00 3.05 V
TM Available Current ITM 100 µA
TM Gain ATM 10 mV/°C
TM Voltage Ripple VTM_PP CTM = 0pF, VIN = 48V, IOUT = 25A 120 200 mV
Digital
Input /
Output
Transition TM Capacitance (External) CTM_EXT 50 pF
TM Fault Response Time tFR_TM From fault to TM = 1.5V 10 µs
Standby TM Voltage VTM_DIS 0 V
TM Pull Down (Internal) RTM_INT Internal pull down-resistor 25 40 50
Reserved: RSV
Reserved for factory use. No connection should be made to this pin.
VICOR’
BCM® Bus Converter Rev 1.9
Page 7 of 21 01/2021
BCM48Bx120y300A00
Timing Diagram
12
34
56
VUVLO+
PC
5V
3V
LL • K
A: tON1
B: tOVLO*
C: tAUTO_RESTART
D: tUVLO
E: tON2
F: tOCP
G: tPC–DIS
H: tSCP**
1: Controller start
2: Controller turn off
3: PC release
4: PC pulled low
5: PC released on output SC
6: SC removed
VOUT
TM
3V @ 27°C
0.4V
VIN
3 V 5 V
2.5 V
500mS
before retrial
VUVLO
A
B
E
H
ISSP
IOUT
IOCP
G
F
D
C
VOVLO+
VOVLO
VOVLO+
NL
Notes:
Timing and signal amplitudes are not to scale
– Error pulse width is load dependent
*Min value switching off
**From detection of error to power train shut down
C
/// /// VICOR
BCM® Bus Converter Rev 1.9
Page 8 of 21 01/2021
BCM48Bx120y300A00
Application Characteristics
The following values, typical of an application environment, are collected at TCASE = 25°C unless otherwise noted.
See associated figures for general trend data.
Input Voltage (V)
Power Dissipation (W)
-40°C 25°C 100°C
4
5
6
7
8
9
10
11
12
38 40 42 44 46 47 49 51 53 55
TCASE:
Case Temperature (°C)
Full Load Efficiency (%)
38V 48V 55V
VIN:
94.0
94.5
95.0
95.5
96.0
96.5
-40 -20 02040608
01
00
Load Current (A)
Efficiency (%)
VIN:38V 48V 55V
67
72
77
82
87
92
97
0510 15 20 25
Figure 2 — No load power dissipation vs. Vin Figure 3 — Full load efficiency vs. temperature; Vin
Figure 4 — Efficiency at TCASE = –40°C
Load Current (A)
Efficiency (%)
VIN:38V 48V 55V
78
83
88
93
98
0510 15 20 25
Figure 6 — Efficiency at TCASE = 25°C
Load Current (A)
38V 48V 55V
VIN:
Power Dissipation (W)
0510 15 20 25
0
5
10
15
20
25
30
Figure 5 — Power dissipation at TCASE = –40°C
Load Current (A)
38V 48V 55V
VIN:
Power Dissipation (W)
0510 15 20 25
0
6
12
18
24
Figure 7 — Power dissipation at TCASE = 25°C
H VICOR
BCM® Bus Converter Rev 1.9
Page 9 of 21 01/2021
BCM48Bx120y300A00
Application Characteristics (Cont.)
The following values, typical of an application environment, are collected at TCASE = 25°C unless otherwise noted.
See associated figures for general trend data.
Load Current (A)
Ripple (mV pk-pk)
48V
VIN:
25
45
65
85
105
125
145
0510 15 20 25
Figure 11 — Vripple vs. Iout: no external Cout, board-mounted
module, scope setting: 20MHz analog BW
Load Current (A)
Efficiency (%)
VIN:38V 48V 55V
78
83
88
93
98
0510 15 20 25
Figure 8 — Efficiency at TCASE = 100°C
Case Temperature (°C)
ROUT (mΩ)
IOUT:12.5A 25A
4
6
8
10
12
14
-40 -20 02040608
01
00
Figure 10 — ROUT vs. temperature; nominal input
Load Current (A)
38V 48V 55V
VIN:
Power Dissipation (W)
0510 15 20 25
0
6
12
18
24
Figure 9 — Power dissipation at TCASE = 100°C
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BCM® Bus Converter Rev 1.9
Page 10 of 21 01/2021
BCM48Bx120y300A00
Figure 13 — Start up from application of PC;
Vin pre-applied Cout = 1000µF
Figure 12 — Full load ripple, 330µF Cin: No external Cout, board
mounted module, scope setting: 20MHz analog BW
Figure 15 — 25 – 0A transient response: Cin = 330µF, Iin measured
prior to Cin, no external Cout
Figure 14 0 – 25A transient response: Cin = 330µF, Iin measured
prior to Cin , no external Cout
Application Characteristics (Cont.)
The following values, typical of an application environment, are collected at TCASE = 25°C unless otherwise noted.
See associated figures for general trend data.
VICOR
BCM® Bus Converter Rev 1.9
Page 11 of 21 01/2021
BCM48Bx120y300A00
General Characteristics
Specifications apply over all line and load conditions, unless otherwise noted; boldface specifications apply over the temperature range of
–40°C ≤ TCASE ≤ 100°C (T-Grade); All other specifications are at TCASE = 25°C unless otherwise noted.
Attribute Symbol Conditions / Notes Min Typ Max Unit
Mechanical
Length L 32.25 [1.270] 32.50 [1.280] 32.75 [1.289] mm [in]
Width W 21.75 [0.856] 22.00 [0.866] 22.25 [0.876] mm [in]
Height H 6.48 [0.255] 6.73 [0.265] 6.98 [0.275] mm [in]
Volume Vol No heat sink 4.81 [0.294] cm3 [in3]
Weight W 14.5 [0.512] g [oz]
Lead Finish
Nickel 0.51 2.03
µm
Palladium 0.02 0.15
Gold 0.003 0.051
Thermal
Operating Temperature TJ
BCM48Bx120T300A00 (T-Grade) –40 125 °C
BCM48Bx120M300A00 (M-Grade) –55 125
Thermal Resistance θJC
Isothermal heatsink and
isothermal internal PCB 1 °C/W
Thermal Capacity 5 Ws/°C
Assembly
Peak Compressive Force
Applied to Case (Z-Axis) Supported by J-lead only 6 lbs
5.41 lbs / in2
Storage Temperature TST
BCM48Bx120T300A00 (T-Grade) –40 125 °C
BCM48Bx120M300A00 (M-Grade) –65 125 °C
ESD Withstand
ESDHBM Human Body Model,
JEDEC JESD 22-A114D.01 Class 1D 1000
V
ESDCDM Charge Device Model,
JEDEC JESD 22-C101-D 400
Soldering
Peak Temperature During Reflow RoHS 245 °C
Non-RoHS 225
Peak Time Above Liquidus Requires AN:009 compliance 60 90 s
Peak Heating Rate During Reflow Requires AN:009 compliance 1 1.5 3 °C/s
Peak Cooling Rate Post Reflow Requires AN:009 compliance 1 1.5 6 °C/s
Safety
Working Voltage (IN – OUT) VIN_OUT 60 VDC
Isolation Voltage (Hipot) VHIPOT 2250 VDC
Isolation Capacitance CIN_OUT Unpowered unit 2500 3200 3800 pF
Isolation Resistance RIN_OUT At 500VDC 10
MTBF
MIL-HDBK-217Plus Parts Count - 25°C
Ground Benign, Stationary, Indoors /
Computer Profile
6.03 MHrs
Telcordia Issue 2 - Method I Case III;
25°C Ground Benign, Controlled 7.94 MHrs
Agency Approvals / Standards
cTÜVus
cURus
CE Marked for Low Voltage Directive and ROHS recast directive, as applicable.
VICOR’
BCM® Bus Converter Rev 1.9
Page 12 of 21 01/2021
BCM48Bx120y300A00
Using The Control Signals PC, TM
Primary Control (PC) pin can be used to accomplish the
following functions:
Logic enable and disable for module: Once tON1 time has
been satisfied, a PC voltage greater than VPC_EN will cause the
module to start. Bringing PC lower than VPC_DIS will cause the
module to enter standby.
Auxiliary voltage source: Once enabled in regular operational
conditions (no fault), each BCM module PC provides a regulated
5V, 3.5mA voltage source.
Synchronized start up: In an array of parallel modules, PC
pins should be connected to synchronize start up across units.
This permits the maximum load and capacitance to scale by the
number of paralleled modules.
Output disable: PC pin can be actively pulled down in order
to disable the module. Pull-down impedance shall be lower
than 60Ω.
Fault-detection flag: The PC 5V voltage source is internally
turned off as soon as a fault is detected.
Note that PC can not sink significant current during a fault
condition. The PC pin of a faulted module will not cause
interconnected PC pins of other modules to be disabled.
Temperature Monitor (TM) pin provides a voltage proportional
to the absolute temperature of the converter control IC.
It can be used to accomplish the following functions:
Monitor the control IC temperature: The temperature in
Kelvin is equal to the voltage on the TM pin scaled by 100.
(i.e., 3.0V = 300K = 27°C). If a heat sink is applied, TM can be
used to protect the system thermally.
Fault-detection flag: The TM voltage source is internally
turned off as soon as a fault is detected. For system monitoring
purposes microcontroller interface faults are detected on falling
edges of TM signal.
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BCM® Bus Converter Rev 1.9
Page 13 of 21 01/2021
BCM48Bx120y300A00
The Sine Amplitude Converter (SAC™) uses a high-frequency
resonant tank to move energy from input to output. The resonant
LC tank, operated at high frequency, is amplitude modulated as
a function of input voltage and output current. A small amount
of capacitance embedded in the input and output stages
of the module is sufficient for full functionality and is key to
achieving power density.
The BCM48Bx120y300A00 SAC can be simplified into the
preceeding model.
At no load:
K represents the “turns ratio” of the SAC.
Rearranging Equation 1:
In the presence of a load, VOUT is represented by:
and IOUT is represented by:
ROUT represents the impedance of the SAC, and is a function of
the RDS_ON of the input and output MOSFETs and the winding
resistance of the power transformer. IQ represents the quiescent
current of the SAC control, gate drive circuitry and core losses.
The use of DC voltage transformation provides additional
interesting attributes. Assuming that ROUT = 0Ω and IQ = 0A,
Equation 3 now becomes Equation 1 and is essentially load
independent, resistor R is now placed in series with VIN.
The relationship between VIN and VOUT becomes:
Substituting the simplified version of Equation 4
(IQ is assumed = 0A) into Equation 5 yields:
This is similar in form to Equation 3, where ROUT is used to
represent the characteristic impedance of the SAC. However, in this
case a real R on the input side of the SAC is effectively scaled by
K2 with respect to the output.
Assuming that R = 1Ω, the effective R as seen from the secondary
side is 62.5mΩ, with K = 1/4.
+
+
VOUT
VIN
V•I
K
+
+
CIN
2µF
IQ
109mA
1/4 • IOUT 1/4 • VIN
RCIN
0.57mΩ
COUT
47µF
RCOUT
430µΩ
LIN
5.7nH
LOUT
600pH
ROUT
9.0mΩ
IOUT
973pH
3.13Ω
R
SAC™
K = 1/4
VIN
VOUT
+
Figure 17 — K = 1/4 Sine Amplitude Converter with
series input resistor
Figure 16 — VI Chip® module AC model
Sine Amplitude Converter™ Point-of-Load Conversion
V
OUT
= V
IN
K(1)
K =
V
OUT
V
IN
(2)
IOUT =
I
IN
– I
Q
K
(4)
V
OUT
= V
IN
• K – I
OUT
• R
OUT
(3)
V
OUT
= (V
IN
– I
IN
• R)K(5)
VOUT = VIN • K – IOUT • R • K2(6)
dV dz (8) P am : P P *PNiPNLiP :P +P m ’ DISSII'ATED — P7P 1 7P (10) (11) VICOR’
BCM® Bus Converter Rev 1.9
Page 14 of 21 01/2021
BCM48Bx120y300A00
A similar exercise should be performed with the additon of a
capacitor or shunt impedance at the input to the SAC. A switch in
series with VIN is added to the circuit. This is depicted in Figure 18.
A change in VIN with the switch closed would result in a change in
capacitor current according to the following equation:
Assume that with the capacitor charged to VIN, the switch is
opened and the capacitor is discharged through the idealized
SAC. In this case,
substituting Equations 1 and 8 into Equation 7 reveals:
The equation in terms of the output has yielded a K2 scaling factor
for C, specified in the denominator of the equation.
A K factor less than unity results in an effectively larger capacitance
on the output when expressed in terms of the input. With a
K = 1/4 as shown in Figure 18, C = 1µF would appear as
C = 16µF when viewed from the output.
Low impedance is a key requirement for powering a high-current,
low-voltage load efficiently. A switching regulation stage
should have minimal impedance while simultaneously providing
appropriate filtering for any switched current. The use of a SAC
between the regulation stage and the point-of-load provides a
dual benefit of scaling down series impedance leading back to
the source and scaling up shunt capacitance or energy storage
as a function of its K factor squared. However, the benefits are
not useful if the series impedance of the SAC is too high. The
impedance of the SAC must be low, i.e., well beyond the crossover
frequency of the system.
A solution for keeping the impedance of the SAC low involves
switching at a high frequency. This enables small magnetic
components because magnetizing currents remain low. Small
magnetics mean small path lengths for turns. Use of low-loss core
material at high frequencies also reduces core losses.
The two main terms of power loss in the BCM module are:
No-load power dissipation (PNL): defined as the power
used to power up the module with an enabled powertrain
at no load.
Resistive loss (PROUT): refers to the power loss across
the BCM modeled as pure resistive impedance.
Therefore,
The above relations can be combined to calculate the overall
module efficiency:
C
S
SAC™
K = 1/4
VIN
VOUT
+
Figure 18 — Sine Amplitude Converter™ with input capacitor
IC (t) = C
dV
IN
dt
(7)
IOUT = (9)
C
K 2
dV
OUT
dt
I
C
= I
OUT
K(8)
P
DISSIPATED
= P
NL
+ P
ROUT
(10)
P
OUT
= P
IN
– P
DISSIPATED
= P
IN
– P
NL
– P
ROUT
(11)
P
OUT
PIN
P
IN
– P
NL
– P
ROUT
PIN
VIN • IIN – PNL(IOUT)2 • ROUT
VIN • IIN
(PNL + (IOUT)2 • ROUT)
VIN • IIN
= 1 –
η =
=
=(
12)
VICOR’
BCM® Bus Converter Rev 1.9
Page 15 of 21 01/2021
BCM48Bx120y300A00
Input and Output Filter Design
A major advantage of SAC™ systems versus conventional PWM
converters is that the transformers do not require large
functional filters. The resonant LC tank, operated at extreme high
frequency, is amplitude modulated as a function of input voltage
and output current and efficiently transfers charge through the
isolation transformer. A small amount of capacitance embedded
in the input and output stages of the module is sufficient for full
functionality and is key to achieve power density.
This paradigm shift requires system design to carefully evaluate
external filters in order to:
Guarantee low source impedance:
To take full advantage of the BCM’s dynamic response, the
impedance presented to its input terminals must be low from
DC to approximately 5MHz. The connection of the bus converter
module to its power source should be implemented with minimal
distribution inductance. If the interconnect inductance exceeds
100nH, the input should be bypassed with a RC damper to
retain low source impedance and stable operation. With an
interconnect inductance of 200nH, the RC damper may be as
high as 1μF in series with 0.3Ω. A single electrolytic or equivalent
low-Q capacitor may be used in place of the series RC bypass.
Further reduce input and/or output voltage ripple without
sacrificing dynamic response:
Given the wide bandwidth of the module, the source response
is generally the limiting factor in the overall system response.
Anomalies in the response of the source will appear at the
output of the module multiplied by its K factor. This is illustrated
in Figures 14 and 15.
Protect the module from overvoltage transients imposed
by the system that would exceed maximum ratings and
cause failures:
The module input/output voltage ranges shall not be exceeded.
An internal overvoltage lockout function prevents operation
outside of the normal operating input range. Even during this
condition, the powertrain is exposed to the applied voltage and
power MOSFETs must withstand it. A criterion for protection
is the maximum amount of energy that the input or output
switches can tolerate if avalanched.
Total load capacitance at the output of the BCM shall not exceed
the specified maximum. Owing to the wide bandwidth and
low output impedance of the module, low-frequency bypass
capacitance and significant energy storage may be more densely
and efficiently provided by adding capacitance at the input of
the module. At frequencies <500kHz the module appears as an
impedance of ROUT between the source and load.
Within this frequency range, capacitance at the input appears as
effective capacitance on the output per the relationship defined
in Equation 13.
This enables a reduction in the size and number of capacitors used
in a typical system.
Thermal Considerations
VI Chip® products are multi-chip modules whose temperature
distribution varies greatly for each part number as well as with the
input / output conditions, thermal management and environmental
conditions. Maintaining the top of the BCM48Bx120y300A00 case
to less than 100°C will keep all junctions within the VI Chip module
below 125°C for most applications.
The percent of total heat dissipated through the top surface
versus through the J-lead is entirely dependent on the particular
mechanical and thermal environment. The heat dissipated through
the top surface is typically 60%. The heat dissipated through the
J-lead onto the PCB surface is typically 40%. Use 100% top surface
dissipation when designing for a conservative cooling solution.
It is not recommended to use a VI Chip module for an extended
period of time at full load without proper heat sinking.
COUT =
C
IN
K
2 (13)
VICOR’
BCM® Bus Converter Rev 1.9
Page 16 of 21 01/2021
BCM48Bx120y300A00
Figure 19 BCM module array
Current Sharing
The performance of the SAC™ topology is based on efficient
transfer of energy through a transformer without the need of
closed loop control. For this reason, the transfer characteristic
can be approximated by an ideal transformer with a positive
temperature coefficient series resistance.
This type of characteristic is close to the impedance characteristic
of a DC power distribution system both in dynamic (AC) behavior
and for steady state (DC) operation.
When multiple BCM modules of a given part number are
connected in an array they will inherently share the load current
according to the equivalent impedance divider that the system
implements from the power source to the point of load.
Some general recommendations to achieve matched array
impedances include:
Dedicate common copper planes within the PCB
to deliver and return the current to the modules.
Provide as symmetric a PCB layout as possible among modules
Apply same input / output filters (if present) to each unit.
For further details see AN:016 Using BCM Bus Converters
in High Power Arrays.
Fuse Selection
In order to provide flexibility in configuring power systems
VI Chip® modules are not internally fused. Input line fusing
of VI Chip products is recommended at system level to provide
thermal protection in case of catastrophic failure.
The fuse shall be selected by closely matching system
requirements with the following characteristics:
Current rating (usually greater than maximum current
of BCM module)
Maximum voltage rating (usually greater than the maximum
possible input voltage)
Ambient temperature
Nominal melting I2t
Recommend fuse: ≤ 10A Littlefuse Nano2 Fuse.
Reverse Operation
BCM modules are capable of reverse power operation. Once the
unit is started, energy will be transferred from secondary back
to the primary whenever the secondary voltage exceeds VIN • K.
The module will continue operation in this fashion for as long as
no faults occur.
The BCM48Bx120y300A00 has not been qualified for continuous
operation in a reverse power condition. Furthermore fault
protections which help protect the module in forward operation
will not fully protect the module in reverse operation.
Transient operation in reverse is expected in cases where there is
significant energy storage on the output and transient voltages
appear on the input. Transient reverse power operation of less
than 10ms, 10% duty cycle is permitted and has been qualified to
cover these cases.
BCM®1
R0_1
ZIN_EQ1 ZOUT_EQ1
ZOUT_EQ2
VOUT
ZOUT_EQn
ZIN_EQ2
ZIN_EQn
R0_2
R0_n
BCM®2
BCM®n
Load
DC
VIN
+
TOP VIEW (CUMPONENT SIDE SHOWN) BOTTOM VIEW m [571 V W, Haas _ “3' T m 0mm A T . m...“ a 1c w my ‘1’” W Mus w P a. m a \ I7 (555! a a q m t [559! fi . “ '1 a Jan} 1 ”L 92a fi‘" ~ ‘2‘ n \ um a (3:11 fl w W m m m; 7 » a: new fixm m m 7m m a, < 307="" ‘="" ,m.="" ‘\="" .="" m="" ‘z="" n="" m="" l="" 7mm“="" m="">< [um="" \="" 1="" mm="" d:="" m="" 3‘="" r="" 7m?”="" 7="" n="">< m="" y.="" o="" .="" m="" ‘7,="" 9="" mm="" w="" w="" m="" m="" a="" w="" »="" k="" ¥="" ,.="" n="" m="" a="" (1:5!="" m="" w="" m="" l/="" w="" m="" m="" a="" ,an="" p.="" n="" w="" [35;="" a)="L" j="" as».="" m="" at="" a="" (1va="" 4/="" \="" w="" m="" ‘="" \="" 1“="" ‘2‘="" n="" j="" ,snn="" u="" w="" ”r="" (2va="" r5391="" 0="" 1357="" £1va="" u="" [susy="" \="" 1“="" mm="" 1:="" mr="" w»!="" (tour-maw!="" mm="" mm="" 1="" e="" 1="" bambi="" vllw="" fl="" _="" ‘="" h2="" m="" mm»="" la“="" mm="" “m="" a="" -="" u="" mm="" '="" 5am="" pm="" 1*="" ‘="" ‘l’="" “0="" 122="" via:="" luau="" ‘51="" mm="" wsw="" onuua="" [maul="" ll="" ‘5="" lam="" sent.="" 117="" r="" scnll="" my="" “1601="" [my="" m‘-="" w="" 5m:-="" m="" m="" p="" m,="" m="" recommended="" land="" pattern="" (cdmpunent="" side="" shown)="" 41="" “5="" um="" 1,31%="" mm="" ‘2‘="" k="" .="" ”a="" “="" hm="" 2‘="" n="" ‘c="" ”a="" ,‘="" hst]="" 2‘="" n="" use="" ‘="" ‘="" f="" [l72]="" 2="" ’="" [wi="" n="" :="" aimmmu="" mm="" ”1751)?”="" :mwm="" m.="" smnm="" vicor’="">
BCM® Bus Converter Rev 1.9
Page 17 of 21 01/2021
BCM48Bx120y300A00
mm
[inch]
NOTES:
1. DIMENSIONS ARE
2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE:
.X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005]
3. PRODUCT MARKING ON TOP SURFACE
DXF and PDF files are available on vicorpower.com
mm
[inch]
NOTES:
1. DIMENSIONS ARE
2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE:
.X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005]
3. PRODUCT MARKING ON TOP SURFACE
DXF and PDF files are available on vicorpower.com
mm
[inch]
NOTES:
1. DIMENSIONS ARE
2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE:
.X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005]
3. PRODUCT MARKING ON TOP SURFACE
DXF and PDF files are available on vicorpower.com
mm
[inch]
NOTES:
1. DIMENSIONS ARE
2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE:
.X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005]
3. PRODUCT MARKING ON TOP SURFACE
DXF and PDF files are available on vicorpower.com
J-Lead Package Recommended Land Pattern
J-Lead Package Mechanical Drawing
"WM, mzazs A ms om («03‘ [m 325 0777+77 WWW ’x ms} m, W! M s» m (3951’ ‘ an mm 7j 99 um] mm Ymv 15 my mm. m m‘omsvl‘ W» m, an (Susy “ ”L 1 mm Kim M, 7 m n m um my?“ 7 ”‘1 m m J mm m mg, m n T o ,, mam ‘ L W m m r [H731 ‘ < 77‘="" mm="" (2051="" "3="" a,="" m="" #="" ”m="" w="" m="" a="" 7/="" as“="" 1"="" 9»="" m="" n="" 44/="" mu="" a="" 57="" w="" [5071="" m="" ”l="" a521)="" ‘7‘="" v‘="" w="" um="" w:="" 22m="" 5="" ‘2="" [32m="" x="" [5531="" ’1’“="" m="" m="" m="" m="" m="" a="" [sum="" ‘1’="" ”l="" \="" ,f="" x555)="" w="" m="" n="" ham="" 4="" azn="" ‘z="" n="" \="" *="" m="" m="" a="" w“="" {2:}="" \m="" 13m="" \="" w,="" m="" 1="" m="" w="" \="" 7="" 3‘="" [3731="" “l="" m="" 1‘="" um="" i="" l="" \="" kg”;="" m="" m="" no="" ml="" f="" 2""="" ml="" 1="" 7="" an="" a="" n="" ‘2"="" umj’="" ”0”="" m="" 5="" 307="" w="" (w!="" 57‘="" (may="" 1‘="" l="" mu="" m="" 0va="" j="" fags,="" m="" m="" m="" m="" v="" mu="" 1/="" m="" 57="" mm="" m="" m="" 5»="" a12="" (="" mm="" mm="" vicor’="">
BCM® Bus Converter Rev 1.9
Page 18 of 21 01/2021
BCM48Bx120y300A00
TOP VIEW ( COMPONENT SIDE )
BOTTOM VIEW
NOTES:
1. DIMENSIONS ARE
2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE:
X.X [X.XX] = ±0.25 [0.01]; X.XX [X.XXX] = ±0.13 [0.005]
3. RoHS COMPLIANT PER CST-0001 LATEST REVISION
DXF and PDF files are available on vicorpower.com
mm
[inch]
NOTES:
1. DIMENSIONS ARE
2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE:
X.X [X.XX] = ±0.25 [0.01]; X.XX [X.XXX] = ±0.13 [0.005]
3. RoHS COMPLIANT PER CST-0001 LATEST REVISION
DXF and PDF files are available on vicorpower.com
mm
[inch]
RECOMMENDED HOLE PATTERN
( COMPONENT SIDE SHOWN )
TOP VIEW ( COMPONENT SIDE )
BOTTOM VIEW
NOTES:
1. DIMENSIONS ARE
2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE:
X.X [X.XX] = ±0.25 [0.01]; X.XX [X.XXX] = ±0.13 [0.005]
3. RoHS COMPLIANT PER CST-0001 LATEST REVISION
DXF and PDF files are available on vicorpower.com
mm
[inch]
NOTES:
1. DIMENSIONS ARE
2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE:
X.X [X.XX] = ±0.25 [0.01]; X.XX [X.XXX] = ±0.13 [0.005]
3. RoHS COMPLIANT PER CST-0001 LATEST REVISION
DXF and PDF files are available on vicorpower.com
mm
[inch]
RECOMMENDED HOLE PATTERN
( COMPONENT SIDE SHOWN )
Through Hole Package Recommended Land Pattern
Through Hole Package Mechanical Drawing
# ’ "a?“ , :T E win \W\\ E 7 , fir L mm W , ;: E ¢ fl . +r mm m ‘mmw . m mam VICOR’
BCM® Bus Converter Rev 1.9
Page 19 of 21 01/2021
BCM48Bx120y300A00
Notes:
1. Maintain 3.50 [0.138] Dia. keep-out zone
free of copper, all PCB layers.
2. (A) Minimum recommended pitch is 39.50 (1.555).
This provides 7.00 [0.275] component
edge-to-edge spacing, and 0.50 [0.020]
clearance between Vicor heat sinks.
(B) Minimum recommended pitch is 41.00 [1.614].
This provides 8.50 [0.334] component
edge-to-edge spacing, and 2.00 [0.079]
clearance between Vicor heat sinks.
3. VI Chip® module land pattern shown for reference
only; actual land pattern may differ.
Dimensions from edges of land pattern
to push–pin holes will be the same for
all full-size VI Chip® products.
4. RoHS compliant per CST–0001 latest revision.
(NO GROUNDING CLIPS) (WITH GROUNDING CLIPS)
5. Unless otherwise specified:
Dimensions are mm [inches]
tolerances are:
x.x (x.xx) = ±0.3 [0.01]
x.xx (x.xxx) = ±0.13 [0.005]
6. Plated through holes for grounding clips (33855)
shown for reference, heat sink orientation and
device pitch will dictate final grounding solution.
Recommended Heat Sink Push Pin Location
VICOR’
BCM® Bus Converter Rev 1.9
Page 20 of 21 01/2021
BCM48Bx120y300A00
Revision History
Revision Date Description Page Number(s)
1.9 01/04/21 Provided additional information to soldering guidelines 11
VICOR
BCM® Bus Converter Rev 1.9
Page 21 of 21 01/2021
BCM48Bx120y300A00
Contact Us: http://www.vicorpower.com/contact-us
Vicor Corporation
25 Frontage Road
Andover, MA, USA 01810
Tel: 800-735-6200
Fax: 978-475-6715
www.vicorpower.com
email
Customer Service: custserv@vicorpower.com
Technical Support: apps@vicorpower.com
©2020 Vicor Corporation. All rights reserved. The Vicor name is a registered trademark of Vicor Corporation.
All other trademarks, product names, logos and brands are property of their respective owners.
Vicor’s comprehensive line of power solutions includes high density AC-DC and DC-DC modules and
accessory components, fully configurable AC-DC and DC-DC power supplies, and complete custom
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Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is assumed by Vicor for its use. Vicor makes
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and other quality controls are used to the extent Vicor deems necessary to support Vicor’s product warranty. Except where mandated by
government requirements, testing of all parameters of each product is not necessarily performed.
Specifications are subject to change without notice.
Visit http://www.vicorpower.com/dc-dc/isolated-fixed-ratio/lv-bus-converter-module for the latest product information.
Vicor’s Standard Terms and Conditions and Product Warranty
All sales are subject to Vicor’s Standard Terms and Conditions of Sale, and Product Warranty which are available on Vicor’s webpage
(http://www.vicorpower.com/termsconditionswarranty) or upon request.
Life Support Policy
VICOR’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE
EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF VICOR CORPORATION. As used
herein, life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and
whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to
result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform
can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. Per Vicor Terms
and Conditions of Sale, the user of Vicor products and components in life support applications assumes all risks of such use and indemnifies
Vicor against all liability and damages.
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Vicor and its subsidiaries own Intellectual Property (including issued U.S. and Foreign Patents and pending patent applications) relating to the
products described in this data sheet. No license, whether express, implied, or arising by estoppel or otherwise, to any intellectual property
rights is granted by this document. Interested parties should contact Vicor’s Intellectual Property Department.
The products described on this data sheet are protected by the following U.S. Patents Numbers:
5,945,130; 6,403,009; 6,710,257; 6,911,848; 6,930,893; 6,934,166; 6,940,013; 6,969,909; 7,038,917; 7,145,786; 7,166,898; 7,187,263;
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