Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
_____________________________________________________________
ASTEC POWER - Andover 1 of 14
REV Description Date Approved
PR-A Preliminary Release 4/30/00
PR-B Preliminary Release 9/05/00
PR-C Remove 1.5, 2, 5V unit – misc.
updates 3/28/01 KTF
TECHNICAL REFERENCE
NOTES (TRN)
BK60C-H SERIES
HIGH EFFICIENCY
DC-DC CO NVERTER
ASTEC POWER
ANDOVER, MA
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 2 of 14
Electrical Spec if ications
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device.
These are absolute stress ratings only. Functional operation of the device in not implied at these
or any other conditions in excess of those given in the operational sections of the TRN. Exposure
to absolute maximum ratings for extended periods can adversely affect device reliability.
Table 1. Absolute Maximum Ratings
Parameter Device Symbol Min Typ Max Unit
Input Voltage:
Continuous:
Transient (100ms) All
All VI
VI, trans
0
0-
-80
100 Vdc
Vdc
Operating Case Temperature All Tc -40 - 100 ºC
Storage Temperature All Tstg -55 - 125 ºC
Operating Humidity All - - - 95 %
I/O Isolation All - - - 1500 Vdc
Input Specifications
Table 2. Input Specifications
Parameter Device Symbol Min Typ Max Unit
Operating Input Voltage All VI36 48 75 Vdc
Maximum Input Current
(VI = 0 to VI,max: Io = Io,max) 018FX
025FX
033FX
II,max
II,max
II,max
-
-
-
-
-
-
3.0
4.0
5.0
A
A
A
Input Reflected-ripple Current
(5Hz to 20MHz: 12uH source
impedance: TA = 25 ºC.) See Figure 9.
All II-10 -mAp-p
No Load Input Power
(VI = VI,nom ) All - - - 7.5 W
Internal Input Capacitance All - - - 3.7 uF
Output Specifications
Table 3. Output Specifications
Parameter Device Symbol Min Typ Max Unit
Output Volta ge Set poi nt
(VI = VI,min to VI,max: Io = Io,max ;
TA = 25 ºC )
018FX
025FX
033FX
Vo,set
Vo,set
Vo,set
1.77
2.46
3.25
1.8
2.5
3.3
1.83
2.54
3.35
Vdc
Vdc
Vdc
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 3 of 14
Output Specifications (continued)
Table 3. Output Specifications (continued)
Parameter Device Symbol Min Typ Max Unit
Output Regulation:
Line (VI = VI,min to VI,max)
Load(Io = Io,min to Io,max)
Temperature (Tc = -40 ºC to +100 ºC)
All -
-
-
-
-
-
0.05
0.1
15
0.2
0.3
50
%Vo
%Vo
mV
Output Ripple and Noise
(Across 0. 1uF ceramic and 10uF
tantalum capacitors ) See Figure 10.
All - - - 150 mVp-p
External Load Capacitance All -
--
--
-10,000 uF
Output Current 018FX
025FX
033FX
Io
Io
Io
0.5
0.5
0.5
-
-
-
40
40
40
A
A
A
Output Current- limit Inceptio n
(Vo = 90% Vo,set) All Io 45 - 55 A
Output Shor t-c irc uit Cur rent
(Vo = 250mV) All - - - 190 %Io,max
Efficiency
(VI = VI,nom ; Io = Io,max;
Tc = 25°C)
018FX
025FX
033FX
Io
Io
Io
80
82
84
82
84
86
-
-
-
%
%
%
Switching Frequency 018FX
025FX
033FX
f
f
f
-
-
-
330
330
400
-
-
-
kHz
kHz
kHz
Dynamic Response:
(Io/t = 1A/10us; VI = VI,nom ; Tc =
70 ºC )
Load Change from Io = 50% to
75% of Io, max:
Peak Deviation
Settling Time
Load Change from Io = 50% to
25% of Io, max:
Peak Deviation
Settling Time
All
All
-
-
-
-
-
-
-
-
-
-
-
-
6
300
6
300
%Vo
usec
%Vo
usec
Turn-on Time
(Io = Io,max; Vo within 1%) All - - 2 5 msec
Output Volta ge O vers hoo t
(Io = Io,max; Tc = 70 ºC) All - - - 5 %Vo
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 4 of 14
Isolation Specifications
Table 4. Isolation Specifications
Parameter Device Symbol Min Typ Max Unit
Isolation Capacitance All - - 2300 - pF
Isolation Resistance All - - 1000 - Mohm
General Specifications
Table 5. General Specifications
Parameter Device Symbol Min Typ Max Unit
Calculated MTBF
(Io = Io,max; TA = 25 ºC)All - - TBD - hours
Weight All - - - 100(3.5) g (oz.)
Feature Specifications
Table 6. Feature Specifications
Parameter Device Symbol Min Typ Max Unit
Remote On/Off Signal Interface:
(VI = 0 to VI,max ; Open collector or
equivalent co mpatible; Signal
referenced to VI (-) terminal.)
Positive Logic – No Suffix
Low Logic – Module Off
High Logic – Module On
Negative Logic –Suffix “N”
Low Logic – Module On
High Logic – Module Off
Module Sp ecifications :
On/Off Current – Logic Low
On/Off Voltage:
Logic Low
Logic High (Ion/off = 0)
Open Collector Switch
Specifications:
Leakage Current – Logic High
(Von/off = 10V)
Output Voltage – Logic Low
(Ion/off = 1mA)
All
All
All
All
All
Ion/off
Von/off
Von/off
Ion/off
Von/off
-
-0.7
-
-
-
-
-
-
-
-
1.0
1.2
10
50
1.2
mA
V
V
uA
V
Output Volta ge Adj us tment
Remote Sense Range
Voltage Adjustment Range All
All -
--
90 -
-0.5
110 V
%Vo
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 5 of 14
Feature Specifications (continued)
Table 6. Feature Specifications (continued)
Parameter Device Symbol Min Typ Max Unit
Output Overvoltage Clamp 018FX
025FX
033FX
Vo,clamp
Vo,clamp
Vo,clamp
2.4
3.1
3.9
-
-
-
2.7
3.5
4.6
V
V
V
Overtem per ature Shu t do wn All T c 105 110 120 ºC
Undervoltage Lockout
Turn-on Point
Turn-off Point All
All -
--
32 34.5
32.5 35
-V
V
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 6 of 14
Characteristic Curves
Figure 1. Typical Input Current vs Input Voltage.
Figure 2. 018F Efficiency vs Load Current. Figure 3. 025F Efficiency vs Load Current.
Figure 4. 033F Efficiency vs Load Current.
BK60C-048L-033F40H
Effici ency vs Outp ut Current
Tc = 25 Deg Celsius
50%
55%
60%
65%
70%
75%
80%
85%
90%
95%
0 5 10 15 20 25 30 35 40
Output Current (Amps)
Vin = 36 Vdc
Vin = 48 Vdc
Vin = 75 Vdc
BK60C-048L-033F40H
Input Current (Worst Case)
Tc = 25 C, Iout = 40A
0
1
2
3
4
5
6
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Vin (Volts)
BK60C-048L-018F40H
Effici ency vs Outp ut Current
Tc = 25 Deg Celsius
50%
55%
60%
65%
70%
75%
80%
85%
90%
95%
0 5 10 15 20 25 30 35 40
Output Current (Amps)
Vin = 36V dc
Vin = 48V dc
Vin = 75V dc
BK60C-048L-025F40H
Effici ency vs Outp ut Current
Tc = 25 Deg Celsius
50%
55%
60%
65%
70%
75%
80%
85%
90%
95%
0 5 10 15 20 25 30 35 40
Output Current (Amps)
Vin = 36V dc
Vin = 48V dc
Vin = 75V dc
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 7 of 14
Characteristic Curves (continued)
Figure 5. Typical Output Voltage Startup Figure 6. Typical Output Ripple (033F)
Vi = Vi,nom, Io = Io,max. Vi = Vi,nom, Io = Io,max.
Figure 7. Typical Dynamic Response (033F) Figure 8. Typical Dynamic Response (033F)
Step Load Change from 50% to 75% Io,max Step Load Change from 50% to 25% Io,max
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 8 of 14
Test Configurations
Note: Measure input reflected-ripple current with a simulated source inductance (Ltest) of 12 uH. Capacitor
Cs offsets possible battery impedance. Measure current as shown above.
Figure 9. Input Reflecte d-ripple Test Setup.
Note: Use a 0.1 uF ceramic capacitor and a 10 uF tantalum capacitor. Scope measurement should be made
using a BNC socket. Position the load between 51 mm and 76 mm (2 in. and 3 in. ) from module.
Figure 10. Peak-to-Peak Output Noise Measurement Test Setup.
BATTERY Cs 220 uF
ESR < 0.1 OHM
@ 20 ºC, 100 kHz
Ltest
12 uH
33 uF
ESR < 0.7 OHM
@ 20 ºC, 100 kHz
Vi(+)
Vi(-)
TO OSCILLOSCOPE
Vo(+)
Vo(-)
RESISTIVE
LOAD
10 uF0.1 uF SCOPE
COPPER STRIP
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 9 of 14
Feature Descriptions
Output Overvoltage Clamp
The output overvoltage clamp consists of a separate control loop, independent of the primary
control loop. This control loop has a higher voltage setpoint than the primary loop. In a fault
condition the converter goes into “Hiccup Mode”, and the output overvoltage clamp ensures that
the output voltage does not exceed Vo,clamp,max. This secondary control loop provides a
redundant voltage-control that reduces the risk of output overvoltage.
Output Current P rotection
To provide protection in an output overload or short circuit condition, the converter is equipped
with current limiting circuitry and can endure the fault condition for an unlimited duration. At the
point of current-limit inception, the converter goes into “Hiccup Mode”, causing the output current
to be limited both in peak and duration. The converter operates normally once the output current
is brought back into its specified range.
Enable (Optional)
Two enable option are available. Positive Logic Enable, no suffix, and Negative Logic Enable,
suffix “N”. Positive Logic Enable turns the converter on during a logic-high voltage on the enable
pin, and off during a logic-low. Negative Logic Enable turns the converter off during a logic-high
and on during a logic-low.
Output Voltage Adjustment
Output voltage adjustment is accomplished by connecting an external resistor between the Vadj
Pin and either the +Sense or –Sense Pins.
With an external resistor between the Vadj Pin and -Sense Pin (Radj-down) the output voltage set
point (Vo,adj) decreases (see Figure 11). The following equation determines the required external
resistor value to obtain an adjusted output voltage:
Where Radj-down is the resistance value and %Vo,adj is the percent change in the output voltage.
With an external resistor between the Vadj Pin and +Sense Pin (Radj-up) the output voltage set
point (Vo,adj) increases (see Figure 12). The following equation determines the required external
resistor value to obtain an adjusted output voltage:
Where Radj-up is the resistance value and %Vo,adj is the percent change in the output voltage.
Radj_down .
100
,%Vo adj 2 koh
m
Radj_up .
.
Vo ( ),
100 %Vo adj
,
.
1.225%Vo adj
,100 .
2 %Vo adj
,%Vo adj koh
m
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 10 of 14
Figure 11 . Circuit Configuration to Decrease Output Voltage.
Figure 12 . Circuit Configuration to Increase Output Voltage.
+Vin
-Vin
Case
Enable
-Vout
+Vout
-Sense
+Sense
Vadj
Rload
Radj-down
+Vin
-Vin
Case
Enable
-Vout
+Vout
-Sense
+Sense
Vadj
Rload
Radj-up
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 11 of 14
Thermal Considerations
The power converter operates in a variety of thermal environments: however, sufficient cooling
should be provided to help ensure reliable operation of the converter. Heat-dissipating
components are thermally coupled to the case. Heat is removed by conduction, convection and
radiation to the surrounding environment. Proper cooling can be verified by measuring the case
temperature.
Heat Transfer Characteristics
Increasing airflow over the converter enhances the heat transfer via convection. Figure 13 shows
the maximum power that can be dissipated by the converter without exceeding the maximum
case temperature versus local ambient temperature (TA) for natural convection through 2.0 m/s
(400 ft/min).
Systems in which these converters are used generate airflow rates of 0.25 m/s (50 ft/min) due to
other heat dissipating components in the system. Therefore, the natural convection condition
represents airflow rates of approximately 0.25 m/s (50 ft/min). Use of Figure 13 is shown in the
follo wing ex ample.
Example
What is the minimum airflow required for an 033F40H operating at 48 V, an output current of 25
A, and maximum ambient temperature of 55 ºC.
Solution:
Given: Vi = 48 V, Io = 25 A, TA = 55 ºC.
Determine PD (Figure 16): PD = 13 W.
Determine airflow (Figure 16): v = 1.0 m/s (200 ft/min)
Figure 13. Forced Convection Power Derating
BK60C SERIES
Power Derating Curve
0
5
10
15
20
25
30
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110
Ambient Temperature (ºC)
Nat. Conv.
0.5 m/s (100 ft/min)
1.0 m/s (200 ft/min)
2.0 m/s (400 ft/min)
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 12 of 14
Thermal Considerations (continued)
Figure 14. 018F Pwr. Diss. vs Load Current. Figure 15. 025F Pwr. Diss. vs Load Current.
Figure 16. 033F Pwr. Diss. vs Load Current.
BK60C-048L-018F40H
Dissipation vs Output Current
Tc = 100 Deg Cel sius
0
5
10
15
20
25
0 5 10 15 20 25 30 35 40
Output Current (Amps)
Vin = 36 Vd c
Vin = 48 Vd c
Vin = 75 Vd c
BK60C-048L-033F40H
Dissipation vs Output Current
Tc = 100 Deg Cel sius
0
5
10
15
20
25
30
0 5 10 15 20 25 30 35 40
Output Current (Amps)
Vin = 36 Vd c
Vin = 48 Vd c
Vin = 75 Vd c
BK60C-048L-025F40H
Dissipation vs Output Current
Tc = 100 Deg Cel sius
0
5
10
15
20
25
0 5 10 15 20 25 30 35 40
Output Current (Amps)
Vin = 36 Vd c
Vin = 48 Vd c
Vin = 75 Vd c
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
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ASTEC POWER - Andover 13 of 14
Outline Drawing
Tolerances: x.xx +/- 0.02 in (x.x +/- 0.5mm)
x.xxx +/- 0.010 in (x.xx +/- 0.25mm
Pin Assignment
1. -Vin
2. Case
3. Enable (on/off)
4. + Vin
5. - Output
6. - Sense
7. Trim
8. + Sense
9. + Output
All pins are 0.040 diameter except pins 5 & 9 which are 0.080 diameter.
Technical Reference Notes (TRN) BK60C-H Series
36 Vdc to 75 Vdc Inputs, 150 W
_____________________________________________________________
ASTEC POWER - Andover 14 of 14
Table 8 Part Numbers.
Model Designation Part Number
018FN BK60C-048L-018F40HN
025FN BK60C-048L-025F40HN
033FN BK60C-048L-033F40HN
018F BK60C-048L-018F40H
025F BK60C-048L-025F40H
033F BK60C-048L-033F40H
Table 9. Options
Suffix Option
N Negative Logic Enable
No Suffix Positive Logic Enable
-6 3.7 mm Pin Length
-8 2.8 mm Pin Length