Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W Date 4/30/00 9/05/00 3/28/01 Approved
REV Description PR-A Preliminary Release PR-B Preliminary Release PR-C Remove 1.5, 2, 5V unit – misc.
updates
KTF
TECHNICAL REFERENCE NOTES (TRN) BK60C-H SERIES HIGH EFFICIENCY DC-DC CONVERTER
ASTEC POWER ANDOVER, MA
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Electrical Specifications 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 Input Voltage: Continuous: All Transient (100ms) All Operating Case Temperature All Storage Temperature All Operating Humidity All I/O Isolation All
Symbol VI VI, trans Tc Tstg -
Min 0 0 -40 -55 -
Typ -
Max 80 100 100 125 95 1500
Unit Vdc Vdc ºC ºC % Vdc
Input Specifications
Table 2. Input Specifications Parameter Operating Input Voltage Maximum Input Current (VI = 0 to VI,max: Io = Io,max) Input Reflected-ripple Current (5Hz to 20MHz: 12uH source
impedance: TA = 25 ºC.) See Figure 9.
Device All 018FX 025FX 033FX All All All
Symbol VI II,max II,max II,max II -
Min 36 -
Typ 48 10 -
Max 75 3.0 4.0 5.0 7.5 3.7
Unit Vdc A A A mAp-p W uF
No Load Input Power (VI = VI,nom ) Internal Input Capacitance
Output Specifications
Table 3. Output Specifications Parameter Output Voltage Setpoint (VI = VI,min to VI,max: Io = Io,max; TA = 25 ºC ) Device 018FX 025FX 033FX Symbol Vo,set Vo,set Vo,set Min 1.77 2.46 3.25 Typ 1.8 2.5 3.3 Max 1.83 2.54 3.35 Unit Vdc Vdc Vdc
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Output Specifications (continued)
Table 3. Output Specifications (continued) Parameter Output Regulation: Line (VI = VI,min to VI,max)
Load(Io = Io,min to Io,max) Temperature (Tc = -40 ºC to +100 ºC)
Device All
Symbol Io Io Io Io Io Io Io f f f
Min 0.5 0.5 0.5 45 80 82 84 -
Typ 0.05 0.1 15 82 84 86 330 330 400
Max 0.2 0.3 50 150 10,000 40 40 40 55 190 -
Unit %Vo %Vo mV mVp-p uF A A A A
%Io,max
Output Ripple and Noise
(Across 0.1uF ceramic and 10uF tantalum capacitors) See Figure 10.
All All 018FX 025FX 033FX All All 018FX 025FX 033FX 018FX 025FX 033FX
External Load Capacitance Output Current
Output Current-limit Inception
(Vo = 90% Vo,set)
Output Short-circuit Current
(Vo = 250mV)
Efficiency (VI = VI,nom ; Io = Io,max; Tc = 25°C) Switching Frequency
% % % 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 Turn-on Time
(Io = Io,max; Vo within 1%)
All
-
-
-
6 300
%Vo usec
All
-
-
2 -
6 300 5 5
%Vo usec
msec
All All
Output Voltage Overshoot
(Io = Io,max; Tc = 70 ºC)
%Vo
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Isolation Specifications
Table 4. Isolation Specifications Parameter Isolation Capacitance Isolation Resistance Device All All Symbol Min Typ 2300 1000 Max Unit pF Mohm
General Specifications
Table 5. General Specifications Parameter Calculated MTBF (Io = Io,max; TA = 25 ºC) Weight Device All All Symbol Min Typ TBD Max 100(3.5)
Unit hours
g (oz.)
Feature Specifications
Table 6. Feature Specifications Parameter Remote On/Off Signal Interface:
(VI = 0 to VI,max ; Open collector or equivalent compatible; Signal referenced to VI (-) terminal.)
Device
Symbol
Min
Typ
Max
Unit
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 Specifications: 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)
All All All
Ion/off Von/off Von/off
-0.7 -
-
1.0 1.2 10
mA V V
All All All All
Ion/off Von/off -
90
-
50 1.2 0.5 110
uA V V %Vo
Output Voltage – Logic Low
(Ion/off = 1mA)
Output Voltage Adjustment Remote Sense Range Voltage Adjustment Range
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Feature Specifications (continued)
Table 6. Feature Specifications (continued)
Parameter Output Overvoltage Clamp
Overtemperature Shutdown Undervoltage Lockout Turn-on Point Turn-off Point
Device 018FX 025FX 033FX All
Symbol Vo,clamp Vo,clamp Vo,clamp Tc
Min 2.4 3.1 3.9 105
Typ 110
Max 2.7 3.5 4.6 120
Unit V V V ºC V V
All All
-
32
34.5 32.5
35 -
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Characteristic Curves
BK60C-048L-033F40H Input Current (Worst Case) Tc = 25 C, Iout = 40A 6 5 4 3 2 1 0 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 Vin (Volts)
Figure 1. Typical Input Current vs Input Voltage.
BK60C-048L-018F40H Efficiency vs Output Current Tc = 25 Deg Celsius 95% 90% 85% 80% 75% 70% 65% 60% 55% 50% 0 5 10 15 20 25 Output Current (Amps) 30
Vin = 36Vdc Vin = 48Vdc Vin = 75Vdc 95% 90% 85% 80% 75% 70% 65% 60% 55% 50% 35 40 0 5
BK60C-048L-025F40H Efficiency vs Output Current Tc = 25 Deg Celsius
Vin = 36Vdc Vin = 48Vdc Vin = 75Vdc
10
15 20 25 Output Current (Amps)
30
35
40
Figure 2. 018F Efficiency vs Load Current.
Figure 3. 025F Efficiency vs Load Current.
BK60C-048L-033F40H Efficiency vs Output Current Tc = 25 Deg Celsius 95% 90% 85% 80% 75% 70% 65% 60% 55% 50% 0 5 10 15 20 25 Output Current (Amps) 30
Vin = 36 Vdc Vin = 48 Vdc Vin = 75 Vdc
35
40
Figure 4. 033F Efficiency vs Load Current.
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Characteristic Curves (continued)
Figure 5. Typical Output Voltage Startup Vi = Vi,nom, Io = Io,max.
Figure 6. Typical Output Ripple (033F) Vi = Vi,nom, Io = Io,max.
Figure 7. Typical Dynamic Response (033F) Step Load Change from 50% to 75% Io,max
Figure 8. Typical Dynamic Response (033F) Step Load Change from 50% to 25% Io,max
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Test Configurations
TO OSCILLOSCOPE
Ltest 12 uH BATTERY Cs 220 uF ESR < 0.1 OHM @ 20 ºC, 100 kHz 33 uF ESR < 0.7 OHM @ 20 ºC, 100 kHz
Vi(+)
Vi(-)
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 Reflected-ripple Test Setup.
COPPER STRIP Vo(+) 0.1 uF Vo(-) 10 uF SCOPE RESISTIVE LOAD
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.
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
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 Protection 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:
Radj_down
100 %Vo, adj
2 . kohm
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:
Radj_up
Vo. ( 100 %Vo , adj ) 1.225. %Vo , adj
100 2. %Vo, adj . kohm %Vo, adj
Where Radj-up is the resistance value and %Vo,adj is the percent change in the output voltage.
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
-Vin Case
-Vout -Sense
Radj-down
Vadj Enable +Vin +Sense +Vout
Rload
Figure 11 . Circuit Configuration to Decrease Output Voltage.
-Vin Case
-Vout -Sense Vadj
Radj-up Rload
Enable +Vin
+Sense +Vout
Figure 12 . Circuit Configuration to Increase Output Voltage.
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
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 following example. 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)
BK60C SERIES Power Derating Curve 30 25 20 15 10 5 0
25 30 35 40 45 50 55 60 65 70 75 80 85 90
Nat. Conv. 0.5 m/s (100 ft/min) 1.0 m/s (200 ft/min) 2.0 m/s (400 ft/min)
95 100 105 110
Ambient Temperature (ºC)
Figure 13. Forced Convection Power Derating
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Thermal Considerations (continued)
BK60C-048L-018F40H Dissipation vs Output Current Tc = 100 Deg Celsius
25 20 15 10 5 0 0 5 10 15 20 25 Output Current (Amps) 30 35 40
Vin = 36 Vdc Vin = 48 Vdc Vin = 75 Vdc
25 20 15 10 5 0 0 5
BK60C-048L-025F40H Dissipation vs Output Current Tc = 100 Deg Celsius
Vin = 36 Vdc Vin = 48 Vdc Vin = 75 Vdc
10
15 20 25 Output Current (Amps)
30
35
40
Figure 14. 018F Pwr. Diss. vs Load Current.
Vin = 36 Vdc Vin = 48 Vdc Vin = 75 Vdc
Figure 15. 025F Pwr. Diss. vs Load Current.
BK60C-048L-033F40H Dissipation vs Output Current Tc = 100 Deg Celsius 30 25 20 15 10 5 0 0 5 10 15 20 25 Output Current (Amps) 30
35
40
Figure 16. 033F Pwr. Diss. vs Load Current.
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Technical Reference Notes (TRN)
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Outline Drawing Tolerances: x.xx +/- 0.02 in (x.x +/- 0.5mm) x.xxx +/- 0.010 in (x.xx +/- 0.25mm
Pin Assignment 1. 2. 3. 4. 5. 6. 7. 8. 9. -Vin Case Enable (on/off) + Vin - Output - Sense Trim + Sense + Output
All pins are 0.040 diameter except pins 5 & 9 which are 0.080 diameter.
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Technical Reference Notes (TRN)
Table 8 Part Numbers. Model Designation 018FN 025FN 033FN 018F 025F 033F
BK60C-H Series 36 Vdc to 75 Vdc Inputs, 150 W
Part Number BK60C-048L-018F40HN BK60C-048L-025F40HN BK60C-048L-033F40HN BK60C-048L-018F40H BK60C-048L-025F40H BK60C-048L-033F40H
Table 9. Options Suffix N No Suffix -6 -8 Option Negative Logic Enable Positive Logic Enable 3.7 mm Pin Length 2.8 mm Pin Length
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