Data Sheet
March 2008
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
The JC050B, JC075B, JC100B Power Modules use advanced,
surface-mount technology and deliver high-quality, efficient,
compact dc-dc conversion.
Applications
nDistributed power architectures
nWorkstations
nEDP equipment
nTelecommunications
Options
nChoice of remote on/off logic configuration
nHeat sink available for extended operation
nShort Leads: 2.79 mm (0.110 in.)
3.68 mm (0.145 in.)
Features
nSmall size: 61.0 mm x 57.9 mm x 13.1 mm
(2.40 in. x 2.28 in. x 0.52 in.)
nHigh power density
nHigh efficiency: 85% typical
nLow output noise
nConstant frequency
nIndustry-standard pinout
nMetal baseplate
n2:1 input voltage range
nOvertemperature protection (100 W only)
nRemote sense
nRemote on/off
nAdjustable output voltage
nCase ground pin
nUL* Recognized, CSA† Certified, VDE Licensed
*UL is a registered trademark of Underwriters Laboratories, Inc.
†CSA is a registered trademark of Canadian Standards Assn.
Description
The JC050B, JC075B, JC100B Power Modules are dc-dc converters that operate over an input voltage range of
18 Vdc to 36 Vdc and provide a precisely regulated dc output. The outputs are fully isolated from the inputs, allow-
ing versatile polarity configurations and grounding connections. The modules have maximum power ratings from
50 W to 100 W at typical full-load efficiency of 85%.
The sealed modules offer metal baseplate for excellent thermal performance. Threaded-through holes are pro-
vided to allow easy mounting or addition of a heat sink for high-temperature applications. The standard feature set
includes remote sensing, output trim, and remote on/off for convenient flexibility in distributed power applications.
2Lineage Power
Data Sheet
March 200818 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are abso-
lute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operations sections of the data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability.
Electrical Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions.
Table 1. Input Specifications
Fusing Considerations
CAUTION: This power module is not internally fused. An input line fuse must always be used.
This encapsulated power module can be used in a wide variety of applications, ranging from simple stand-alone
operation to an integrated part of a sophisticated power architecture. To preserve maximum flexibility, internal fus-
ing is not included; however, to achieve maximum safety and system protection, always use an input line fuse. The
safety agencies require a normal-blow, dc fuse with a maximum rating of 20 A (see Safety Considerations section).
Based on the information provided in this data sheet on inrush energy and maximum dc input current, the same
type of fuse with a lower rating can be used. Refer to the fuse manufacturer’s data for further information.
Parameter Symbol Min Max Unit
Input Voltage:
Continuous
Transient (100 ms)
VI
VI, trans
—
—
40
50
Vdc
Vdc
I/O Isolation Voltage — — 1500 Vdc
Operating Case Temperature
(See Thermal Considerations section.)
TC–40 100 °C
Storage Temperature Tstg –40 110 °C
Parameter Symbol Min Typ Max Unit
Operating Input Voltage VI18 28 36 Vdc
Maximum Input Current
(VI = 0 V to 36 V; IO = IO, max):
JC050B (See Figure 1)
JC075B (See Figure 2)
JC100B (See Figure 3.)
II, max
II, max
II, max
—
—
—
—
—
—
5.0
7.0
9.0
A
A
A
Inrush Transient i2t——1.0A
2s
Input Reflected-ripple Current, Peak-to-peak
(5 Hz to 20 MHz, 12 µH source impedance;
see Figure 11.)
—— 5 —mAp-p
Input Ripple Rejection (120 Hz) — — 60 — dB
Lineage Power 3
Data Sheet
March 2008 18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Electrical Specifications (continued)
Table 2. Output Specifications
Table 3. Isolation Specifications
Parameter Device Symbol Min Typ Max Unit
Output Voltage
(Over all operating input voltage, resistive load,
and temperature conditions until end of life; see
Figure 13.)
All VO11.64 — 12.36 Vdc
Output Voltage Set Point
(VI = 28 V; IO = IO, max; TC = 25 °C)
All VO, set 11.78 — 12.22 Vdc
Output Regulation:
Line (VI = 18 V to 36 V)
Load (IO = IO, min to IO, max)
Temperature (TC = –40 °C to +100 °C)
All
All
All
—
—
—
—
—
—
0.01
0.05
50
0.1
0.4
150
%
%
mV
Output Ripple and Noise Voltage
(See Figure 12.):
RMS
Peak-to-peak (5 Hz to 20 MHz)
All
All
—
—
—
—
—
—
50
200
mVrms
mVp-p
External Load Capacitance (electrolytic) All — 0 — 5,000 µF
Output Current
(At IO < IO, min, the module may exceed output
ripple specifications.)
JC050B
JC075B
JC100B
IO
IO
IO
0.3
0.3
0.3
—
—
—
4.2
6.3
8.3
A
A
A
Output Current-limit Inception
(VO = 90% of VO, nom)
JC050B
JC075B
JC100B
IO, cli
IO, cli
IO, cli
—
—
—
4.8
6.4
9.6
5.8
8.1
10.8
A
A
A
Output Short-circuit Current (VO = 250 mV) All — — 170 — %IO, max
Efficiency (VI = 28 V; IO = IO, max; TC = 70 °C) JC050B
JC075B
JC100B
η
η
η
82
83
83
85
85
85
—
—
—
%
%
%
Dynamic Response
(ΔIO/Δt = 1 A/10 µs, VI = 28 V, TC = 25 °C):
Load Change from IO = 50% to 75% of IO, max:
Peak Deviation
Settling Time (VO < 10% of peak deviation)
Load Change from IO = 50% to 25% of IO, max:
Peak Deviation
Settling Time (VO < 10% of peak deviation)
All
All
All
All
—
—
—
—
—
—
—
—
2
300
2
300
—
—
—
—
%VO, set
µs
%VO, set
µs
Parameter Min Typ Max Unit
Isolation Capacitance — 2500 — pF
Isolation Resistance 10 — — MΩ
4Lineage Power
Data Sheet
March 200818 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
General Specifications
Feature Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions. See Feature Descriptions for additional information.
Parameter Min Typ Max Unit
Calculated MTBF (IO = 80% of IO, max; TC = 40 °C) 2,600,000 hr.
Weight — — 100 (3.5) g (oz.)
Parameter Symbol Min Typ Max Unit
Remote On/Off Signal Interface
(VI = 0 V to 36 V; open collector or equivalent compatible;
signal referenced to VI(–) terminal; see Figure 14 and
Feature Descriptions.):
JCxxxB1 Preferred Logic:
Logic Low—Module On
Logic High—Module Off
JCxxxB Optional Logic
Logic Low—Module Off
Logic High—Module On
Logic Low:
At Ion/off = 1.0 mA
At Von/off = 0.0 V
Logic High:
At Ion/off = 0.0 µA
At Von/off = 15 V
Turn-on Time (See Figure 10)
(IO = 80% of IO, max; VO within ±1% of steady state)
Von/off
Ion/off
Von/off
Ion/off
—
0
—
—
—
—
—
—
—
—
20
1.2
1.0
15
50
35
V
mA
V
µA
ms
Output Voltage Adjustment (See Feature Descriptions.):
Output Voltage Remote-sense Range
Output Voltage Set-point Adjustment Range (trim)
—
—
—
60
—
—
1.2
110
V
%VO, nom
Output Overvoltage Clamp VO, clamp 13.2 — 16.0 V
Overtemperature Shutdown
(100 W only; see Feature Descriptions.)
Tc — 105 — °C
Lineage Power 5
Data Sheet
March 2008 18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Characteristic Curves
The following figures provide typical characteristics for the JC050B, JC075B, JC100B power modules. The figures
are identical for both on/off configurations.
8-1238 (C)
Figure 1. Typical JC050B Input Characteristics at
Room Temperature, IO = Full Load
8-1238 (C).b
Figure 2. Typical JC075B Input Characteristics at
Room Temperature, IO = Full Load
8-1239 (C)
Figure 3. Typical JC100B Input Characteristics at
Room Temperature, IO = Full Load
8-1240 (C)
Figure 4. Typical JC050B Output Characteristics at
Room Temperature, VIN = 28 V
0 4 8 121620 36
0.0
2.5
3.0
3.5
4.0
INPUT VOLTAGE, VI (V)
2.0
1.5
1.0
0.5
24 28 32
IIN (A)
04 8121620 36
0.0
5.0
6.0
4.0
3.0
2.0
1.0
24 28 32
IIN (A)
INPUT VOLTAGE, VI (V)
0 4 8 121620 36
0
5
6
7
8
INPUT VOLTAGE, VI (V)
4
3
2
1
24 28 32
IIN (A)
012345 7
0
8
10
12
14
OUTPUT CURRENT, IO (A)
VOUT (V)
6
4
2
6
Data Sheet
March 2008
66 Lineage Power
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Characteristic Curves (continued)
8-1240 (C).a
Figure 5. Typical JC075B Output Characteristics at
Room Temperature, VIN = 28 V
8-1241 (C)
Figure 6. Typical JC100B Output Characteristics at
Room Temperature, VIN = 28 V
8-1242 (C).a
Figure 7. Typical JC050B Converter Efficiency vs.
Output Current at Room Temperature
8-1243 (C).a
Figure 8. Typical JC075B Converter Efficiency vs.
Output Current at Room Temperature
01 2 3 4 5 7
0
7
9
12
13
OUTPUT CURRENT, IO (A)
VOUT (V)
6
4
2
6
11
10
8
5
3
1
89
0134678
0
8
10
12
OUTPUT CURRENT, IO (A)
6
4
2
529
VOUT (V)
10
14
0 0.7 1.4 2.1 2.8 3.5 4.2
77
83
84
85
86
OUTPUT CURRENT, IO (A)
EFF (%)
81
80
79
78
82
18 V
28 V
36 V
0
70
82
84
86
OUTPUT CURRENT, IO (A)
EFF (%)
78
76
74
72
80
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5
18 V
28 V
36 V
Lineage Power 7
Data Sheet
March 2008 18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Characteristic Curves (continued)
8-1243 (C).b
Figure 9. Typical JC100B Converter Efficiency vs.
Output Current at Room Temperature
8-1266 (C)
Figure 10.Typical Start-Up from Remote On/Off
JCxxxB1; IO = Full Load
Test Configurations
8-203 (C).l
Note:Measure input reflected-ripple current with a simulated source
inductance (LTEST) of 12 µH. Capacitor CS offsets possible
battery impedance. Measure current as shown above.
Figure 11. Input Reflected-Ripple Test Setup
8-513 (C).d
Note:Use a 1.0 µF ceramic capacitor and a 10 µF aluminum
or 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 the module.
Figure 12. Peak-to-Peak Output Noise
Measurement Test Setup
01 34678
77
83
84
85
86
OUTPUT CURRENT, IO (A)
EFF (%)
81
80
79
78
82
5
2
18 V
28 V
36 V
0 V
0 V
TIME, t (5 ms/div)
OUTPUT VOLTAGE, VO (V)
(5 V/div)
REMOTE ON/OFF
VOLTAGE, VON/OFF (V)
(5 V/div)
TO OSCILLOSCOPE
12 µH
C
S
220 µF
ESR < 0.1 Ω
@ 20 ˚C, 100 kHz
V
I
(+)
V
I
(–)
BATTERY 33 µF
CURRENT
PROBE
L
TEST
ESR < 0.7 Ω
@ 100 kHz
VO(+)
VO(–)
1.0 µF RESISTIVE
LOAD
SCOPE
COPPER STRIP
10 µF
Data Sheet
March 2008
88 Lineage Power
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Test Configurations (continued)
8-749 (C)
Note: All measurements are taken at the module terminals. When
socketing, place Kelvin connections at module terminals to
avoid measurement errors due to socket contact resistance.
Figure 13. Output Voltage and Efficiency
Measurement Test Setup
Design Considerations
Input Source Impedance
The power module should be connected to a low
ac-impedance input source. Highly inductive source
impedances can affect the stability of the power mod-
ule. For the test configuration in Figure 11, a 33 µF
electrolytic capacitor (ESR < 0.7 Ω at 100 kHz)
mounted close to the power module helps ensure sta-
bility of the unit. For other highly inductive source
impedances, consult the factory for further application
guidelines.
Safety Considerations
For safety-agency approval of the system in which the
power module is used, the power module must be
installed in compliance with the spacing and separation
requirements of the end-use safety agency standard,
i.e., UL-1950, CSA 22.2-950, and EN60950.
For the converter output to be considered meeting the
requirements of safety extra-low voltage (SELV), the
input must meet SELV requirements.
If the input meets extra-low voltage (ELV) require-
ments, then the converter’s output is considered ELV.
The input to these units is to be provided with a maxi-
mum 20 A normal-blow fuse in the ungrounded lead.
Electrical Descriptions
Current Limit
To provide protection in a fault (output overload) condi-
tion, the unit is equipped with internal current-limiting
circuitry and can endure current limiting for an unlim-
ited duration. At the point of current-limit inception, the
unit shifts from voltage control to current control. If the
output voltage is pulled very low during a severe fault,
the current-limit circuit can exhibit either foldback or tai-
lout characteristics (output current decrease or
increase). The unit operates normally once the output
current is brought back into its specified range.
Feature Descriptions
Remote On/Off
Two remote on/off options are available. Positive logic
remote on/off turns the module on during a logic-high
voltage on the ON/OFF pin, and off during a logic low.
Negative logic remote on/off turns the module off dur-
ing a logic high and on during a logic low. Negative
logic (code suffix “1”) is the factory-preferred configura-
tion.
To turn the power module on and off, the user must
supply a switch to control the voltage between the
on/off terminal and the VI(-) terminal (Von/off). The
switch can be an open collector or equivalent (see
Figure 14). A logic low is Von/off = 0 V to 1.2 V. The max-
imum Ion/off during a logic low is 1 mA. The switch
should maintain a logic-low voltage while sinking 1 mA.
During a logic high, the maximum Von/off generated by
the power module is 15 V. The maximum allowable
leakage current of the switch at Von/off = 15 V is 50 μA.
If not using the remote on/off feature, do one of the fol-
lowing:
nFor negative logic, short ON/OFF pin to VI(-)
nFor positive logic, leave ON/OFF pin open.
VI(+)
IIIO
SUPPLY
CONTACT
RESISTANCE
CONTACT AND
DISTRIBUTION LOSSES
LOAD
SENSE(+)
VI(–)
VO(+)
VO(–)
SENSE(–)
η[Vo(+) – Vo(-)]Io
[Vi(+) – Vi(-)]Ii
-------------------------------------------
⎝⎠
⎛⎞
100×=
Lineage Power 9
Data Sheet
March 2008 18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Feature Descriptions (continued)
Remote On/Off (continued)
8-720 (C).c
Figure 14. Remote On/Off Implementation
Remote Sense
Remote sense minimizes the effects of distribution
losses by regulating the voltage at the remote-sense
connections. The voltage between the remote-sense
pins and the output terminals must not exceed the out-
put voltage sense range given in the Feature Specifica-
tions table, i.e.:
[VO(+) – VO(–)] – [SENSE(+) – SENSE(–)] ≤ 1.2 V
The voltage between the VO(+) and VO(–) terminals
must not exceed 5.9 V. This limit includes any increase
in voltage due to remote-sense compensation and out-
put voltage set-point adjustment (trim), see Figure 15.
If not using the remote-sense feature to regulate the
output at the point of load, then connect SENSE(+) to
VO(+) and SENSE(-) to VO(-) at the module.
8-651 (C).h
Figure 15. Effective Circuit Configuration for
Single-Module Remote-Sense Operation
Output Voltage Set-Point Adjustment
(Trim)
Output voltage trim allows the user to increase or
decrease the output voltage set point of a module. This
is accomplished by connecting an external resistor
between the TRIM pin and either the SENSE(+) or
SENSE(–) pins. With an external resistor between the
TRIM and SENSE(–) pins (Radj-down), the output voltage
set point (Vo, adj) decreases (see Figure 16). The follow-
ing equation determines the required external-resistor
value to obtain a percentage output voltage change of
Δ%.
The test results for this configuration are displayed in
Figure 17. This figure applies to all output voltages.
With an external resistor connected between the TRIM
and SENSE(+) pins (Radj-up), the output voltage set
point (VO, adj) increases (see Figure 18).
The following equation determines the required exter-
nal-resistor value to obtain a percentage output voltage
change of Δ%.
The test results for this configuration are displayed in
Figure 19.
The voltage between the VO(+) and VO(–) terminals
must not exceed 5.9 V. This limit includes any increase
in voltage due to remote-sense compensation and out-
put voltage set-point adjustment (trim). See Figure 15.
If not using the trim feature, leave the TRIM pin open.
8-748 (C).c
Figure 16. Circuit Configuration to Decrease
Output Voltage
SENSE(+)
VO(+)
SENSE(–)
VO(–)
VI(–)
+
–
Ion/off
ON/OFF
VI(+)
LOAD
Von/off
VO(+)
SENSE(+)
SENSE(–)
VO(–)
VI(+)
VI(–)
IOLOAD
CONTACT AND
DISTRIBUTION LOSSES
SUPPLY II
CONTACT
RESISTANCE
Radj-down 100
Δ%
----------2–
⎝⎠
⎛⎞
kΩ=
Radj-up VO100 Δ%+()
1.225Δ%
--------------------------------------100 2Δ%+()
Δ%
----------------------------------
–
⎝⎠
⎛⎞
kΩ=
VI(+)
VI(–)
ON/OFF
CASE
VO(+)
VO(–)
SENSE(+)
TRIM
SENSE(–)
Radj-down
RLOAD
Data Sheet
March 2008
1010 Lineage Power
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Feature Descriptions (continued)
Output Voltage Set-Point Adjustment
(Trim) (continued)
8-879 (C)
Figure 17. Resistor Selection for Decreased
Output Voltage
8-715 (C).d
Figure 18. Circuit Configuration to Increase
Output Voltage
8-880a
Figure 19. Resistor Selection for Increased Output
Voltage
Output Overvoltage Clamp
The ouput overvoltage clamp consists of control cir-
cuitry, independent of the primary regulation loop, that
monitors the voltage on the output terminals. The con-
trol loop of the clamp has a higher voltage set point
than the primary loop (see Feature specifications
table). this provides a redundant voltage control that
reduces the risk of output overvoltage.
Overtermperature Protection (Shutdown)
The 100 W module features an overtemperature pro-
tection circuit to safeguard against thermal damage.
The circuit shuts down the module when the maximum
case temperature is exceeded. The module restarts
automatically after cooling.
Thermal Considerations
Introduction
The power modules operate in a variety of thermal
environments; however, sufficient cooling should be
provided to help ensure reliable operation of the unit.
Heat-dissipating components inside the unit are ther-
mally coupled to the case. Heat is removed by conduc-
tion, convection,a nd radiation to the surrounding
environment. Proper cooling can be verified by mea-
suring the case temperature. Peak temperature (Tc)
occurs at the position indicated in Figure 20.
010203040
100
1k
100k
1M
% CHANGE IN OUTPUT VOLTAGE (Δ%)
10k
ADJUSTMENT RESISTOR VALUE (Ω)
VI(+)
VI(–)
ON/OFF
CASE
VO(+)
VO(–)
SENSE(+)
TRIM
SENSE(–)
Radj-up
RLOAD
02 4 6 10
10M
%
CHANGE IN OUTPUT VOLTAGE (
Δ
%)
8
1M
100k
10k
ADJUSTMENT RESISTOR VALUE (
Ω
)
Lineage Power 11
Data Sheet
March 2008 18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Thermal Considerations (continued)
Introduction (continued)
8-716 (C).f
Note: Top view, pin locations are for reference.
Measurements shown in millimeters and (inches).
Figure 20. Case Temperature Measurement
Location
The temperature at this location should not exceed
100 °C. The output power of the module should not
exceed the rated power for the module as listed in the
Ordering Information table.
Although the maximum case temperature of the power
modules is 100 °C, you can limit this temperature to a
lower value for extremely high reliability.
For additional information on these modules, refer to the
Thermal Management JC-, JFC-, JW-, and JFW-Series
50 W to 150 W Board-Mounted Power Modules Technical
Note (TN97-008EPS).
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat
transfer via convection. Figure 21 shows the maximum
power that can be dissipated by the module without
exceeding the maximum case temperature versus local
ambient temperature (TA) for natural convection
through 4 m/s (800 ft./min.).
Note that the natural convection condition was mea-
sured at 0.05 m/s to 0.1 m/s (10 ft./min. to 20 ft./min.);
however, systems in which these power modules may
be used typically generate natural convection airflow
rates of 0.3 m/s (60 ft./min.) due to other heat dissipat-
ing components in the system. The use of Figure 21 is
shown in the following example.
Example
What is the minimum airflow necessary for a JC100B
operating at nominal line, an output current of 8.5 A,
and a maximum ambient temperature of 40 °C?
Solution
Given: VI = 28 V
IO = 8.5 A
TA = 40 °C
Determine PD (Use Figure 24.):
PD = 20 W
Determine airflow (v) (Use Figure 21.):
v = 2.5 m/s (500 ft./min.)
8-1150 (C).a
Figure 21. Forced Convection Power Derating with
No Heat Sink; Either Orientation
8-1249
Figure 22. JC050B Power Dissipation vs.
Output Current
38.0 (1.50) MEASURE CASE
VI(–)
ON/OFF
CASE
+ SEN
TRIM
– SEN
VI(+)
VO(–)
VO(+)
7.6 (0.3)
TEMPERATURE HERE
0 10203040 100
0
35
LOCAL AMBIENT TEMPERATURE, TA (˚C)
POWER DISSIPATION, PD (W)
25
20
10
90
80706050
4.0 m/s (800 ft./mi
n
0.1 m/s (NAT. CONV.)
(20 ft./min.)
0.5 m/s (100 ft./mi
n
1.0 m/s (200 ft./mi
n
1.5 m/s (300 ft./mi
n
2.0 m/s (400 ft./min
2.5 m/s (500 ft./min
3.0 m/s (600 ft./mi
n
3.5 m/s (700 ft./mi
n
5
15
30
0.0 0.6
0
2
8
10
12
OUTPUT CURRENT, IO (A)
POWER DISSIPATION, PD (W)
1.2 1.8
VI = 18
VI = 27
VI = 36
4
6
2.4 3.0 3.6 4.2
Data Sheet
March 2008
1212 Lineage Power
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Thermal considerations (continued)
Heat Transfer Without Heat Sinks (continued)
8-1494
Figure 23. JC075B Power Dissipation vs.
Output Current
8-1250
Figure 24. JC100B Power Dissipation vs.
Output Current
Heat Transfer with Heat Sinks
The power modules have through-threaded, M3 x 0.5
mounting holes, which enable heat sinks or cold plates
to attach to the module. The mounting torque must not
exceed 0.56 N-m (5 in.-lb.).
Thermal derating with heat sinks is expressed by using
the overall thermal resistance of the module. Total
module thermal resistance (θca) is defined as the max-
imum case temperature rise (ΔTC, max) divided by the
module power dissipation (PD):
The location to measure case temperature (TC) is
shown in Figure 20. Case-to-ambient thermal resis-
tance vs. airflow is shown, for various heat sink config-
urations and heights, in Figure 25. These curves were
obtained by experimental testing of heat sinks, which
are offered in the product catalog.
8-1153
Figure 25. Case-to-Ambient Thermal Resistance
Curves; Either Orientation
These measured resistances are from heat transfer
from the sides and bottom of the module as well as the
top side with the attached heat sink; therefore, the
case-to-ambient thermal resistances shown are gener-
ally lower than the resistance of the heat sink by itself.
The module used to collect the data in Figure 25 had a
thermal-conductive dry pad between the case and the
heat sink to minimize contact resistance. The use of
Figure 25 is shown in the following example
0
0
2
4
8
16
20
OUTPUT CURRENT, IO (A)
POWER DISSIPATION, PD (W)
6
14
18
12
10
0.5 1 1.5 2 2.5 3 3.5 4
VI = 24 V
VI = 18 V
VI = 36 V
4.5 5 5.5 6 6.5
0.0 1.0 2.0 3.0
0
5
10
15
20
25
OUTPUT CURRENT, IO (A)
POWER DISSIPATION, PD (W)
4.0 5.0 7.06.0 8.0
VI = 18
VI = 28
VI = 36
θca ΔTCmax,
PD
---------------------TCTA–()
PD
------------------------
==
00.5
(100)
1.0
(200)
1.5
(300)
2.0
(400)
2.5
(500)
3.0
(600)
0
1
5
6
7
8
AIR VELOCITY MEASURED IN m/s (ft./min.)
4
3
2
CASE-TO-AMBIENT THERMAL
RESISTANCE, RCA (°C/W)
1 1/2 IN HEAT SINK
1 IN HEAT SINK
1/2 IN HEAT SINK
1/4 IN HEAT SINK
NO HEAT SINK
Lineage Power 13
Data Sheet
March 2008 18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Thermal considerations (continued)
Heat Transfer with Heat Sinks (continued)
Example
If an 85 °C case temperature is desired, what is the
minimum airflow necessary? Assume the JC100B
module is operating at nominal line and an output cur-
rent of 8.5 A, maximum ambient air temperature of
40 °C, and the heat sink is 0.5 in.
Solution
Given: VI = 28 V
IO = 8.5 A
TA = 40 °C
TC = 85 °C
Heat sink = 0.5 in.
Determine PD by using Figure 24:
PD = 20 W
Then solve the following equation:
Use Figure 25 to determine air velocity for the0.5 inch
heat sink.
The minimum airflow necessary for the JC100B mod-
ule is 1.7 m/s (340 ft./min.).
Custom Heat Sinks
A more detailed model can be used to determine the
required thermal resistance of a heat sink to provide
necessary cooling. The total module resistance can be
separated into a resistance from case-to-sink (θcs) and
sink-to-ambient (θsa) shown below (Figure 26).
8-1304
Figure 26. Resistance from Case-to-Sink and
Sink-to-Ambient
For a managed interface using thermal grease or foils,
a value of θcs = 0.1 °C/W to 0.3 °C/W is typical. The
solution for heat sink resistance is:
This equation assumes that all dissipated power must
be shed by the heat sink. Depending on the user-
defined application environment, a more accurate
model, including heat transfer from the sides and bot-
tom of the module, can be used. This equation pro-
vides a conservative estimate for such instances.
Layout Considerations
Copper paths must not be routed beneath the power
module mounting inserts.
θca TCTA–()
PD
------------------------
=
θca 85 40–()
20
------------------------
=
θca 2.3 °C/W=
PD
TCTSTA
θcs θsa
→
θsa TCTA–()
PD
-------------------------θcs–=
Data Sheet
March 2008
1414 Lineage Power
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Outline Diagram
Dimensions are in millimeters and (inches).
Tolerances: x.x mm ± 0.5 mm (x.xx in. ± 0.02 in.)
x.xx mm ± 0.25 mm (x.xxx in. ± 0.010 in.)
Top View
Side View
Bottom View
8-1190
* Side labels include Lineage name, product designation, safety agency markings, input/output voltage and current ratings, and bar code.
57.9 (2.28) MAX
61.0
(2.40)
MAX
5.1 (0.20) MIN
13.08 ± 0.5
(0.515 ± 0.020)
2.06 (0.081) DIA
SOLDER-PLATED BRASS,
2 PLACES–(OUTPUT AND
+OUTPUT)
1.02 (0.040) DIA
SOLDER-PLATED
BRASS, 7 PLCS
SIDE LABELS*
10.16
(0.400)
–SEN
TRIM
+SEN
CASE
ON/OFF
MOUNTING INSERTS
M3 x 0.5 THROUGH,
4 PLACES
10.16
(0.400)
5.1 (0.20)
48.3 (1.90)
48.26
(1.900)
12.7 (0.50)
4.8
(0.19)
17.78
(0.700)
25.40
(1.000)
35.56
(1.400)
25.40
(1.000)
50.8
(2.00)
35.56
(1.400)
VI (–) VO (–)
VO (+)VI (+)
15 Lineage Power
Data Sheet
March 200818 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
Recommended Hole Pattern
Component-side footprint.
Dimensions are in millimeters and (inches).
8-1190
Ordering Information
Input
Voltage
Output
Voltage
Output
Power
Remote On/
Off Logic
Device
Code Comcode
28 V 12.0 V 50 W negative JC050B1 107201667
28 V 12.0 V 75 W negative JC075B1 107310005
28 V 12.0 V 100 W negative JC100B1 107201683
28 V 12.0 V 50 W positive JC050B 107361479
28 V 12.0 V 75 W positive JC075B 107477184
28 V 12.0 V 100 W positive JC100B 107309940
10.16
(0.400)
10.16
(0.400)
12.7 (0.50)
48.3 (1.90)
48.26
(1.900)
4.8
(0.19)
MOUNTING INSERTS
MODULE OUTLINE
5.1 (0.20)
57.9 (2.28) MAX
17.78
(0.700)
25.40
(1.000)
35.56
(1.400)
25.40
(1.000)
50.8
(2.00)
35.56
(1.400)
61.0
(2.40)
MAX
–SEN
TRIM
+SEN
CASE
ON/OFF
VI (+) VO (+)
VO (–)
VI (–)
Option Features
Optional features can be ordered using the suffixes
shown in Table 4. The suffixes follow the last letter of
the device code and are placed in descending order.
For example, the device codes for a JC100B module
with the following options are shown below:
Positive logic JC100B
Negative logic JC100B1
Positive logic and 2.79 mm leads JC100B8
Negative logic and 2.79 mm leadsJC100B81
Negative logic and 3.68 mm leadsJC100B61
Table 4. Module Options and Suffixes
Option Suffix
Short lead 2.79 mm (0.110 in.) 8
Short lead 3.68 mm (0.145 in.) 6
Negative remote on/off logic 1
Positive remote on/off logic —
Data Sheet
March 200818 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
March2008
DS97-278EPS (Replaces DS97-277EPS)
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