Data Sheet
April 2008
FC250F1 Power Module: dc-dc Converter;
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
The FC250F1 Power Module uses advanced, surface-mount
technology and delivers high-quality, compact, dc-dc
conversion at an economical price.
Applications
nRedundant and distributed power architectures
nComputer equipment
nCommunications equipment
Options
nHeat sinks available for extended operation
Features
nSize: 61.0 mm x 116.8 mm x 13.5 mm
(2.40 in. x 4.60 in. x 0.53 in.)
nWide input voltage range
nHigh efficiency: 78% typical
nParallel operation with load sharing
nAdjustable output voltage
nOvertemperature protection
nOutput voltage set-point adjustment (trim)
nSynchronization
nPower good signal
nOutput current monitor
nOutput overvoltage and overcurrent protection
nRemote sense
nRemote on/off
nConstant frequency
nCase ground pin
nInput-to-output isolation
nISO* 9001 Certified manufacturing facilities
nUL†1950 Recognized, CSA
‡ C22.2 No. 950-95
Certified, and VDE § 0805 (EN60950, IEC950)
Licensed
Description
The FC250F1 Power Module is a dc-dc converter that operates over an input voltage range of 18 Vdc to 36 Vdc
and provides a precisely regulated dc output. The outputs are fully isolated from the inputs, allowing versatile
polarity configurations and grounding connections. The module has a maximum power rating of 165 W at a typ-
ical full-load efficiency of 78%.
Two or more modules may be paralleled with forced load sharing for redundant or enhanced power applications.
The package, which mounts on a printed-circuit board, accommodates a heat sink for high-temperature
applications.
*ISO is a registered trademark of the International Organization of Standardization.
†UL is a registered trademark of Underwriters Laboratories, Inc.
‡CSA is a registered trademark of Canadian Standards Association.
§ VDE is a trademark of Verband Deutscher Elektrotechniker e.V.
2Lineage Power
Data Sheet
April 2008
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
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.
Parameter Symbol Min Max Unit
Input Voltage (continuous) VI—50 Vdc
I/O Isolation Voltage (for 1 minute) — — 1500 Vdc
Operating Case Temperature
(See Thermal Considerations section and
Figure 18.)
TC–40 100 °C
Storage Temperature Tstg –55 125 °C
Electrical Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions.
Table 1. Input Specifications
Parameter Symbol Min Typ Max Unit
Operating Input Voltage VI18 28 36 Vdc
Maximum Input Current (VI = 0 V to 36 V) II, max — — 15 A
Inrush Transient i2t — — 4.0 A2s
Input Reflected-ripple Current, Peak-to-peak
(5 Hz to 20 MHz, 12 µH source impedance;
see Figure 8.)
II — 10 —mAp-p
Input Ripple Rejection (120 Hz) — — 60 —dB
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 fuse with a maximum rating of 25 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.
Lineage Power 3
Data Sheet
April 2008 18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Electrical Specifications (continued)
Table 2. Output Specifications
Parameter Symbol Min Typ Max Unit
Output Voltage Set Point
(VI = 28 V; IO = IO, max; TC = 25 °C)
VO, set 3.25 3.3 3.35 Vdc
Output Voltage
(Over all operating input voltage, resistive load,
and temperature conditions until end of life; see
Figure 10 and Feature Descriptions.)
VO3.20 —3.40 Vdc
Output Regulation:
Line (VI = 18 V to 36 V)
Load (IO = IO, min to IO, max)
Temperature (TC = –40 °C to +100 °C)
—
—
—
—
—
—
0.01
0.05
15
0.1
0.2
50
%VO
%VO
mV
Output Ripple and Noise Voltage
(See Figures 4 and 9.):
RMS
Peak-to-peak (5 Hz to 20 MHz)
—
—
—
—
—
—
40
150
mVrms
mVp-p
External Load Capacitance — 0 — * µF
Output Current
(At IO < IO, min, the modules may exceed output
ripple specifications.)
IO0.5 —50 A
Output Current-limit Inception
(VO = 90% of VO, set; see Feature Descriptions.)
IO, cli 51.5 57.5 65†%IO, max
Output Short-circuit Current
(VO = 1.0 V; indefinite duration, no hiccup mode;
see Figure 2.)
———150 %IO, max
Efficiency
(VI = 28 V; IO = IO, max; TC = 25 °C;
see Figures 3 and 10.)
η—78 — %
Switching Frequency — — 500 — kHz
Dynamic Response
(ýIO/ýt = 1 A/10 µs, VI = 28 V, TC = 25 °C; tested
with a 10 µF aluminum and a 1.0 µF ceramic
capacitor across the load; see Figures 5 and 6.):
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)
—
—
—
—
—
—
—
—
50
200
50
200
—
—
—
—
mV
µs
mV
µs
* Consult your sales representative or the factory.
† These are manufacturing test limits. In some situations, results may differ.
4Lineage Power
Data Sheet
April 2008
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Electrical Specifications (continued)
Table 3. Isolation Specifications
Parameter Min Typ Max Unit
Isolation Capacitance —1700 —pF
Isolation Resistance 10 — — M¾
General Specifications
Parameter Min Typ Max Unit
Calculated MTBF (IO = 80% of IO, max; TC = 40 °C) 1,900,000 hours
Weight — — 200 (7) g (oz.)
Feature Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions. See Feature Descriptions for further information.
Table 4. Feature Specifications
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 11 and Feature Descriptions.):
Logic Low—Module On
Logic High—Module Off
Logic Low:
At Ion/off = 1.0 mA
At Von/off = 0.0 V
Logic High:
At Ion/off = 0.0 µA
Leakage Current
Turn-on Time
(IO = 80% of IO, max; VO within ±1% of steady state)
Output Voltage Overshoot
Von/off
Ion/off
Von/off
Ion/off
—
—
0
—
—
—
—
—
—
—
—
—
30
0
1.2
1.0
15
50
50
5
V
mA
V
µA
ms
%VO, set
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 Protection —4* —5* V
Output Current Monitor (IO = IO, max, TC = 70 °C) IO, mon —0.067 —V/A
Synchronization:
Clock Amplitude
Clock Pulse Width
Fan-out
Capture Frequency Range
—
—
—
—
4.00
0.4
—
450
—
—
—
—
5.00
—
1
550
V
µs
—
kHz
* These are manufacturing test limits. In some situations, results may differ.
Lineage Power 5
Data Sheet
April 2008 18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Feature Specifications (continued)
Table 4. Feature Specifications (continued)
Parameter Symbol Min Typ Max Unit
Overtemperature Protection (See Figure 18.) TC—105 —°C
Forced Load Share Accuracy — — 10 —%IO, rated
Power Good Signal Interface
(See Feature Descriptions.):
Low Impedance—Module Operating
High Impedance—Module Off
Rpwr/good
Ipwr/good
Rpwr/good
Vpwr/good
—
—
1
—
—
—
—
—
100
1
—
40
¾
mA
M¾
V
Solder, Cleaning, and Drying Considerations
Post solder cleaning is usually the final circuit-board assembly process prior to electrical testing. The result of inad-
equate circuit-board cleaning and drying can affect both the reliability of a power module and the testability of the
finished circuit-board assembly. For guidance on appropriate soldering, cleaning, and drying procedures, refer to
Board-Mounted Power Modules Soldering and Cleaning Application Note (AP97-021EPS).
66 Lineage Power
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter; Data Sheet
April 2008
Characteristic Curves
The following figures provide typical characteristics for the power module.
12
10
0
INPUT VOLTAGE, VI (V)
INPUT CURRENT, II (A)
8
6
4
2
0
510152025303540
IO = 50 A
IO = 25 A
IO = 5 A
8-2875 (F)
Figure 1. Typical FC250F1 Input Characteristics at
Room Temperature
3.5
3
0
OUTPUT CURRENT, IO (A)
OUTPUT VOLTAGE, VO (V)
2.5
2
1.5
1
0.5
20 30 40 50 60 70
0
10
VI = 36 V
VI = 28 V
VI = 18 V
8-3277 (F)
Figure 2. Typical FC250F1 Output Characteristics
at Room Temperature
81
80
0
OUTPUT CURRENT, IO (A)
EFFICIENCY, η (%)
79
78
77
76
71
5 101520253035 50
VI = 18 V
VI = 28 V
VI = 36 V
75
74
73
72
40 45
8-2876 (F)
Figure 3. Typical FC250F1 Efficiency vs. Output
Current at Room Temperature
TIME, t (500 ns/div)
OUTPUT VOLTAGE, VO (A)
(20 mV/div)
VI = 36 V
VI = 28 V
VI = 18 V
8-2877 (F)
Note: See Figure 9 for test conditions.
Figure 4. Typical FC250F1 Output Ripple Voltage at
Room Temperature and 50 A Output
Lineage Power 7
Data Sheet
April 2008 18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Characteristic Curves (continued)
TIME, t (20 μs/div)
OUTPUT VOLTAGE, VO (V)
(100 mV/div)
OUTPUT CURRENT, IO (A)
(5 A/div)
8-2881 (F)
Note: Tested with a 10 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
Figure 5. Typical FC250F1 Transient Response to
Step Decrease in Load from 50% to 25%
of Full Load at Room Temperature and
28 V Input (Waveform Averaged to
Eliminate Ripple Component.)
TIME, t (20 μs/div)
OUTPUT VOLTAGE, VO (V)
(100 mV/div)
OUTPUT CURRENT, IO (A)
(5 A/div)
8-2878 (F)
Note: Tested with a 10 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
Figure 6. Typical FC250F1 Transient Response to
Step Increase in Load from 50% to 75% of
Full Load at Room Temperature and 28 V
Input (Waveform Averaged to Eliminate
Ripple Component.)
TIME, t (5 ms/div)
OUTPUT VOLTAGE, VO (V)
(1 V/div)
NO CAPACITANCE
5870 μF FULL LOAD
2200 μF FULL LOAD
1000 μF FULL LOAD
470 μF FULL LOAD
NO LOAD
8-2882 (F)
Note: Tested with a 10 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
Figure 7. Typical FC250F1 Start-Up Transient at
Room Temperature, 28 V Input, and Full
Load
88 Lineage Power
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter; Data Sheet
April 2008
Test Configurations
TO OSCILLO SCOPE
12 µH
V
I
(+)
V
I
(–)
BATTERY
L
TES T
Cs 220 µF
ESR < 0.1 •
@ 20 °C, 100 kHz 100 µF
ESR < 0.3 •
@ 100 kHz
8-203 (C).o
Note: Measure input reflected-ripple current with a simulated source
inductance (LTEST) of 12 µH. Capacitor CS offsets possible bat-
tery impedance. Measure current as shown above.
Figure 8. Input Reflected-Ripple Test Setup
V
O
(+)
V
O
(–)
1.0 µF RESISTIVE
LOAD
SCOPE
COPPER STRIP
10.0 µF
8-513 (C).m
Note: Use a 0.1 µF ceramic capacitor and a 10 µF aluminum or
tantalum capacitor. Scope measurement should be made
using a BNC socket. Position the load between 50 mm and
76 mm (2 in. and 3 in.) from the module.
Figure 9. Peak-to-Peak Output Noise Measurement
Test Setup
V
I
(–)
V
O
(+)
SENSE(+)
SENSE(–)
V
O
(–)
V
I
(+)
I
O
LOAD
CONTACT AND
DISTRIBUTION LOSSES
SUPPLY I
I
CONTACT
RESISTANCE
8-683 (C).f
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.
ηVO+()–VO–()[]IO
VI+()–VI–()[]II
--------------------------------------------------
⎝⎠
⎛⎞
x 100 %=
Figure 10. 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 8, a 100 µF
electrolytic capacitor (ESR < 0.3 ¾ 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 No. 95-950, and VDE 0805
(EN60950, IEC950).
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 25 A normal-blow fuse in the ungrounded lead.
Feature Descriptions
Overcurrent Protection
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
tailout characteristics (output-current decrease or
increase). The unit operates normally once the output
current is brought back into its specified range.
Lineage Power 9
Data Sheet
April 2008 18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Feature Descriptions (continued)
Remote On/Off
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 11). A logic
low is Von/off = 0 V to 1.2 V, during which the module is on.
The maximum 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, short the
ON/OFF pin to VI(–).
+
I
on/off
–
V
on/off
CASE
ON/OFF
V
I
(+)
V
I
(–)
SENSE(+)
SENSE(–)
V
O
(+)
V
O
(–)
8-580 (C).d
Figure 11. 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(–)] ð 1.2 V
The voltage between the VO(+) and VO(–) terminals
must not exceed the minimum value indicated in the
output overvoltage protection section of the Feature
Specifications table. This limit includes any increase in
voltage due to remote-sense compensation and output
voltage set-point adjustment (trim), see Figure 12.
If not using the remote-sense feature to regulate the out-
put at the point of load, connect SENSE(+) to VO(+) and
SENSE(–) to VO(–) at the module.
Although the output voltage can be increased by both
the remote sense and by the trim, the maximum
increase for the output voltage is not the sum of both.
The maximum increase is the larger of either the
remote sense or the trim. Consult the factory if you
need to increase the output voltage more than the
above limitation.
The amount of power delivered by the module is
defined as the voltage at the output terminals multiplied
by the output current. When using remote sense and
trim, the output voltage of the module can be
increased, which at the same output current would
increase the power output of the module. Care should
be taken to ensure that the maximum output power of
the module remains at or below the maximum rated
power.
V
O
(+)
SENSE(+)
SENSE(–)
V
O
(–)
V
I
(+)
V
I
(–)
I
O
LOAD
CONTACT AND
DISTRIBUTION LOSSES
SUPPLY I
I
CONTACT
RESISTANCE
8-651 (C).e
Figure 12. 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. The trim resistor should be positioned
close to the module.
If not using the trim feature, leave the TRIM pin open.
With an external resistor between the TRIM and
SENSE(–) pins (Radj-down), the output voltage set point
(VO, adj) decreases (see Figure 13). The following equa-
tion determines the required external-resistor value to
obtain a percentage output voltage change of ý%.
Radj-down 205
Δ%
----------2.255–
⎝⎠
⎛⎞
kΩ=
The test results for this configuration are displayed in
Figure 14. This figure applies to all output voltages.
1010 Lineage Power
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter; Data Sheet
April 2008
Feature Descriptions (continued)
Output Voltage Set-Point Adjustment
(Trim) (continued)
With an external resistor connected between the TRIM
and SENSE(+) pins (Radj-up), the output voltage set
point (VO, adj) increases (see Figure 15).
The following equation determines the required exter-
nal-resistor value to obtain a percentage output voltage
change of ý%.
Radj-up
VO, nom 1Δ%
100
----------
+()1.225–()
1.225Δ%
()
------------------------------------------------------------------------- 205 2.255
–
⎝⎠
⎜⎟
⎜⎟
⎛⎞
kΩ=
The test results for this configuration are displayed in
Figure 16.
The voltage between the VO(+) and VO(–) terminals
must not exceed the minimum value of the output over-
voltage protection as indicated in the Feature Specifi-
cations table. This limit includes any increase in
voltage due to remote-sense compensation and output
voltage set-point adjustment (trim). See Figure 12.
Although the output voltage can be increased by both
the remote sense and by the trim, the maximum
increase for the output voltage is not the sum of both.
The maximum increase is the larger of either the
remote sense or the trim. Consult the factory if you
need to increase the output voltage more than the
above limitation.
The amount of power delivered by the module is
defined as the voltage at the output terminals multiplied
by the output current. When using remote sense and
trim, the output voltage of the module can be
increased, which at the same output current would
increase the power output of the module. Care should
be taken to ensure that the maximum output power of
the module remains at or below the maximum rated
power.
V
I
(+)
V
I
(–)
ON/OFF
CASE
V
O
(+)
V
O
(–)
SENSE(+)
TRIM
SENSE(–)
R
adj-down
R
LOAD
8-748 (C).b
Figure 13. Circuit Configuration to Decrease
Output Voltage
1M
0
% CHANGE IN OUTPUT VOLTAGE (Δ%)
ADJUSTMENT RESISTOR VALUE (Ω)
10k
1k
10 20 40
30
100k
8-2883 (F)
Figure 14. Resistor Selection for Decreased
Output Voltage
V
I
(+)
V
I
(–)
ON/OFF
CASE
V
O
(+)
V
O
(–)
SENSE(+)
TRIM
SENSE (–)
R
adj-up
R
LOAD
8-715 (C).b
Figure 15. Circuit Configuration to Increase
Output Voltage
1M
100k
0
% CHANGE IN OUTPUT VOLTAGE (Δ%)
ADJUSTMENT RESISTOR VALUE (Ω)
10k
24 10
6 8
8-2884 (F)
Figure 16. Resistor Selection for Increased Output
Voltage
Lineage Power 11
Data Sheet
April 2008 18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Feature Descriptions (continued)
Output Overvoltage Protection
The output voltage is monitored at the VO(+) and VO(–)
pins of the module. If the voltage at these pins exceeds
the value indicated in the Feature Specifications table,
the module will shut down and latch off. Recovery from
latched shutdown is accomplished by cycling the dc
input power off for at least 1.0 second or toggling the
primary referenced on/off signal for at least 1.0 second.
Output Current Monitor
The CURRENT MON pin provides a dc voltage propor-
tional to the dc output current of the module given in
the Feature Specifications table. For example, on the
FC250F1, the V/A ratio is set at 67 mV/A ± 10% @
70 °C case. At a full load current of 50 A, the voltage on
the CURRENT MON pin is 3.685 V. The current moni-
tor signal is referenced to the SENSE(–) pin on the
secondary and is supplied from a source impedance of
approximately 2 kΩ. It is recommended that the CUR-
RENT MON pin be left open when not in use, although
no damage will result if the CURRENT MON pin is
shorted to secondary ground. Directly driving the CUR-
RENT MON pin with an external source will detrimen-
tally affect operation of the module and should be
avoided.
Synchronization
Any module can be synchronized to any other module
or to an external clock using the SYNC IN or SYNC
OUT pins. The modules are not designed to operate in
a master/slave configuration; that is, if one module
fails, the other modules will continue to operate.
SYNC IN Pin
This pin can be connected either to an external clock or
directly to the SYNC OUT pin of another FC250x mod-
ule.
If an external clock signal is applied to the SYNC IN
pin, the signal must be a 500 kHz (±50 kHz) square
wave with a 4 Vp-p amplitude. Operation outside this
frequency band will detrimentally affect the perfor-
mance of the module and must be avoided.
If the SYNC IN pin is connected to the SYNC OUT pin
of another module, the connection should be as direct
as possible, and the VI(–) pins of the modules must be
shorted together.
Unused SYNC IN pins should be tied to VI(–). If the
SYNC IN pin is unused, the module will operate from
its own internal clock.
SYNC OUT Pin
This pin contains a clock signal referenced to the VI(–)
pin. The frequency of this signal will equal either the
module’s internal clock frequency or the frequency estab-
lished by an external clock applied to the SYNC IN pin.
When synchronizing several modules together, the
modules can be connected in a daisy-chain fashion
where the SYNC OUT pin of one module is connected
to the SYNC IN pin of another module. Each module in
the chain will synchronize to the frequency of the first
module in the chain.
To avoid loading effects, ensure that the SYNC OUT
pin of any one module is connected to the SYNC IN pin
of only one module. Any number of modules can be
synchronized in this daisy-chain fashion.
Overtemperature Protection
To provide protection in a fault condition, the unit is
equipped with an overtemperature shutdown circuit.
The shutdown circuit will not engage unless the unit is
operated above the maximum case temperature.
Recovery from overtemperature shutdown is
accomplished by cycling the dc input power off for at
least 1.0 second or toggling the primary referenced on/
off signal for at least 1.0 second.
Forced Load Sharing (Parallel Operation)
For either redundant operation or additional power
requirements, the power modules can be configured for
parallel operation with forced load sharing (see
Figure 17). For a typical redundant configuration,
Schottky diodes or an equivalent should be used to
protect against short-circuit conditions. Because of the
remote sense, the forward-voltage drops across the
Schottky diodes do not affect the set point of the
voltage applied to the load. For additional power
requirements, where multiple units are used to develop
combined power in excess of the rated maximum, the
Schottky diodes are not needed.
1212 Lineage Power
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter; Data Sheet
April 2008
Feature Descriptions (continued)
Forced Load Sharing (Parallel Operation)
(continued)
Good layout techniques should be observed for noise
immunity. To implement forced load sharing, the follow-
ing connections must be made:
nThe parallel pins of all units must be connected
together. The paths of these connections should be
as direct as possible.
nAll remote-sense pins should be connected to the
power bus at the same point, i.e., connect all
SENSE(+) pins to the (+) side of the power bus at the
same point and all SENSE(–) pins to the (–) side of
the power bus at the same point. Close proximity and
directness are necessary for good noise immunity.
When not using the parallel feature, leave the
PARALLEL pin open.
V
O
(+)
PARALLEL
SENSE(+)
SENSE(–)
V
O
(–)
CASE
V
I
(+)
ON/OFF
V
I
(–)
V
O
(+)
PARALLEL
SENSE(+)
SENSE(–)
V
O
(–)
CASE
V
I
(+)
ON/OFF
V
I
(–)
8-581 (C)
Figure 17. Wiring Configuration for Redundant
Parallel Operation
Power Good Signal
The PWR GOOD pin provides an open-drain signal
(referenced to the SENSE(–) pin) that indicates the
operating state of the module. A low impedance
(<100 Ω) between PWR GOOD and SENSE(–) indi-
cates that the module is operating. A high impedance
(>1 MΩ) between PWR GOOD and SENSE(–) indi-
cates that the module is off or has failed. The PWR
GOOD pin can be pulled up through a resistor to an
external voltage to facilitate sensing. This external volt-
age level must not exceed 40 V, and the current into
the PWR GOOD pin during the low-impedance state
should be limited to 1 mA maximum.
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, and radiation to the surrounding
environment. Proper cooling can be verified by mea-
suring the case temperature. Peak temperature occurs
at the position indicated in Figure 18.
30.5
(1.20)
82.6
(
3.25
)
CASE
SYNC IN
V
I
(–)
V
I
(+) V
O
(+)
V
O
(–)SYNC OUT
MEASURE CASE
TEMPERATURE HERE
ON/OFF
8-1303 (C).a
Note: Top view, measurements shown in millimeters and (inches).
Pin locations are for reference only.
Figure 18. Case Temperature Measurement
Location
Lineage Power 13
Data Sheet
April 200818 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Thermal Considerations (continued)
Introduction (continued)
The temperature at this location should not exceed
100 °C . The maxim um case temper ature can be limited
to a lower value for extremely high reliability. The output
power of the module should not exceed the rated power
f or the module as listed in the Ordering Information table.
For additional information about these modules, ref er to
the
Thermal Management for FC- and FW-Series 250
W—300 W Board-Mounted Power Modules
Technical
Note (TN96-009EPS).
Heat Transfer Without Heat Sinks
Derating curves for forced-air cooling without a heat
sink are shown in Figures 19 and 20. These curves can
be used to determine the appropriate airflow f or a given
set of operating conditions. For e xample , if the unit with
airflow along its length dissipates 20 W of heat, the
correct airflow in a 40 °C environment is 1.0 m/s
(200 ft./min.).
8-1315 (C)
Figure 19. Convection Power Derating with No Heat
Sink; Airflow Along Width; Transverse
Orientation
8-1314 (C)
Figure 20. Convection Power Derating with No Heat
Sink; Airflow Along Length;
Longitudinal Orientation
Heat Transfer with Heat Sinks
The power modules have through-threaded, M3 x 0.5
mounting holes, which enab le heat sinks or cold plates
to be attached to the module. The mounting torque
must not exceed 0.56 N-m (5 in.-lb.). For a screw
attachment from the pin side, the recommended hole
size on the customer’s PWB around the mounting
holes is 0.130 ± 0.005 inches. If a larger hole is used,
the mounting torque from the pin side must not exceed
0.25 N-m (2.2 in.-lb.).
Thermal derating with heat sinks is expressed b y using
the ov er all thermal resistance of the module. Total mod-
ule thermal resistance (θca) is defined as the maximum
case temperature rise (∆TC, max) divided by the module
power dissipation (PD):
The location to measure case temperature (TC) is
shown in Figure 18. Case-to-ambient thermal resis-
tance vs. airflow for various heat sink configurations is
shown in Figures 21 and 22. These curves were
obtained by experimental testing of heat sinks, which
are offered in the product catalog.
010203040 100
0
40
60
70
LOCAL AMBIENT TEMPERATURE, T
A
(°C)
POWER DISSIPATION, P
D
(W)
30
20
10
9080706050
50
4.0 m/s (800 ft./min.)
3.5 m/s (700 ft./min.)
3.0 m/s (600 ft./min.)
2.5 m/s (500 ft./min.)
2.0 m/s (400 ft./min.)
1.5 m/s (300 ft./min.)
1.0 m/s (200 ft./min.)
0.5 m/s (100 ft./min.)
0.1 m/s (20 ft./min.) NAT. CONV.
010203040 100
0
40
60
70
LOCAL AMBIENT TEMPERATURE, T
A
(°C)
POWER DISSIPATION, P
D
(W)
30
20
10
9080706050
4.0 m/s (800 ft./min.)
3.5 m/s (700 ft./min.)
3.0 m/s (600 ft./min.)
2.5 m/s (500 ft./min.)
2.0 m/s (400 ft./min.)
1.5 m/s (300 ft./min.)
1.0 m/s (200 ft./min.)
0.5 m/s (100 ft./min.)
50
0.1 m/s (20 ft./min.) NAT. CONV.
θca ∆TC max,
PD
---------------------TCTA–()
PD
------------------------
==
1414 Lineage Power
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter; Data Sheet
April 2008
Thermal Considerations (continued)
Heat Transfer with Heat Sinks (continued)
8-1321 (C)
Figure 21. Case-to-Ambient Thermal Resistance
Curves; T ransverse Orientation
8-1320 (C)
Figure 22. Case-to-Ambient Thermal Resistance
Curves; Longitudinal 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 Figures 21 and
22 had a thermal-conductive dry pad between the case
and the heat sink to minimize contact resistance.
To choose a heat sink, determine the power dissipated
as heat by the unit for the particular application.
Figure 23 shows typical heat dissipation for a range of
output currents and three voltages for the FC250F1.
8-2885 (F)
Figure 23. FC250F1 Power Dissipation vs. Output
Current at 25 °C
Example
If an 85 °C case temperature is desired, what is the
minimum airflow necessary? Assume the FC250F1
module is operating at VI = 28 V and an output current
of 40 A, maximum ambient air temperature of 40 °C,
and the heat sink is 1.0 inch.
Solution
Given: VI = 28 V
IO = 40 A
TA = 40 °C
TC = 85 °C
Heat sink = 1.0 inch
Determine PD by using Figure 23:
PD = 35 W
Then solve the following equation:
0.0
0.5
3.0
3.5
4.0
4.5
2.5
2.0
1.0
1 1/2 IN. HEAT SINK
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
1.5
AIR VELOCITY, m/s (ft./min.)
0 0.5
(100) 1.0
(200) 1.5
(300) 2.0
(400) 2.5
(500) 3.0
(600)
CASE-TO-AMBIENT THERMAL
RESISTANCE,
θ
CA
(°C/W)
00.5
(100) 1.0
(200) 1.5
(300) 2.0
(400) 2.5
(500) 3.0
(600)
0.0
0.5
3.0
3.5
4.0
4.5
2.5
2.0
1.0
1 1/2 IN. HEAT SINK
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
1.5
AIR VELOCITY, m/s (ft./min.)
CASE-TO-AMBIENT THERMAL
RESISTANCE,
θ
CA
(°C/W)
50
45
0
OUTPUT CURRENT, IO (A)
POWER DISSIPATION, PD (W)
40
35
30
25
05 101520253035 50
20
15
10
5
40 45
VI = 18 V
VI = 28 V
VI = 36 V
θca TCTA–()
PD
------------------------
=
θca 85 40–()
35
------------------------
=
θca 1.3 °C/W=
Lineage Power 15
Data Sheet
April 2008 18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Thermal Considerations (continued)
Heat Transfer with Heat Sinks (continued)
Use Figures 21 and 22 to determine air velocity for the
1.0 inch heat sink. The minimum airflow necessary for
this module depends on heat sink fin orientation and is
shown below:
n1.0 m/s (200 ft./min.) (oriented along width)
n1.15 m/s (230 ft./min.) (oriented along length)
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) as shown in Figure 24.
P
D
T
C
T
S
T
A
θ
cs
θ
sa
∅
8-1304 (C)
Figure 24. 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:
θsa TCTA–()
PD
-------------------------θcs–=
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.
EMC Considerations
For assistance with designing for EMC compliance,
please refer to the FLTR100V10 data sheet
(DS99-294EPS).
Layout Considerations
Copper paths must not be routed beneath the power
module mounting inserts. For additional layout guide-
lines, refer to the FLTR100V10 data sheet
(DS99-294EPS).
16 Lineage Power
Data Sheet
April 2008
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
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.)
8-1650 (C).a
* Side label includes Lineage name, product designation, safety agency markings, input/output voltage and current ratings, and bar code.
T op View
Side View
Bottom View
CASE
SYNC IN
ON/OFF
V
I
–
V
I
+
2.54 (0.100) TYP
V
O
–
V
O
+
SYNC OUT
SENSE–
SENSE+
TRIM
PARALLEL
CURRENT MON
PWR GOOD
5.1 (0.20)
50.8
(2.00)
30.48
(1.200)
22.86
(0.900)
12.7
(0.50)
5.08
(0.200)
10.16
(0.400) 15.24
(0.600)20.32
(0.800)
25.40
(1.000)
30.48
(1.200)
35.56
(1.400)
66.04 (2.600)
MOUNTING INSERTS
M3 x 0.5 THROUGH,
4 PLACES
5.1 (0.20)
2.54 (0.100) TYP
106.68 (4.200)
7.62
(0.300)
17.78
(0.700)
12.70
(0.500)
13.5
(0.53)
5.1 (0.20) MIN 1.57 ± 0.05 (0.062 ± 0.002) DIA
SOLDER-PLATED BRASS,
11 PLACES
(VOUT–, VOUT+, VIN–, VIN+)
1.02 ± 0.05 (0.040 ± 0.002) DIA
SOLDER-PLATED BRASS,
9 PLACES
SIDE LABEL*
116.8 (4.60)
61.0
(2.40)
Lineage Power 17
Data Sheet
April 2008
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Recommended Hole Pattern
Component-side footprint.
Dimensions are in millimeters and (inches).
8-1650 (C).a
Ordering Information
Table 5. Device Codes
Input V oltage Output V oltage Output Power Device Code Comcode
28 V 3.3 V 165 W FC250F1 108178740
5.1 (0.20)
10.16
(0.400)
M
O
UNTIN
G
IN
S
ERT
S
5.1 (0.20)
2.54 (0.100) TYP
2.54 (0.100) TYP
5.08
(0.200)
15.24
(0.600)
20.32
(0.800)
25.40
(1.000)
30.48
(1.200)
35.56
(1.400)
106.68 (4.200)
66.04 (2.600)
50.8
(2.00)
30.48
(1.200)
22.86
(0.900)
17.78
(0.700)
12.70
(0.500)
12.7
(0.50)
7.62
(0.300)
CASE
SYNC IN
ON/OFF
V
I
–
V
I
+
V
O
–
V
O
+
SENSE–
SENSE+
TRIM
PARALLEL
CURRENT MON
PWR GOOD
SYNC OUT
7.62
(0.300)
7.62
(0.300)
1818 Lineage Power
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter; Data Sheet
April 2008
Ordering Information (continued)
Table 6. Device Accessories
Dimension are in millimeters and (inches).
8-2830 (C)
Figure 25. Longitudinal Heat Sink
8-2831 (C)
Figure 26. Transverse Heat Sink
Accessory Comcode
1/4 in. transverse kit (heat sink, thermal pad, and screws) 847308335
1/4 in. longitudinal kit (heat sink, thermal pad, and screws) 847308327
1/2 in. transverse kit (heat sink, thermal pad, and screws) 847308350
1/2 in. longitudinal kit (heat sink, thermal pad, and screws) 847308343
1 in. transverse kit (heat sink, thermal pad, and screws) 847308376
1 in. longitudinal kit (heat sink, thermal pad, and screws) 847308368
1 1/2 in. transverse kit (heat sink, thermal pad, and screws) 847308392
1 1/2 in. longitudinal kit (heat sink, thermal pad, and screws) 847308384
1/4 IN.
1/2 IN.
1 IN.
1 1/2 IN.
60.45
(2.38)
115.82
(4.56)
1/4 IN.
1/2 IN.
1 IN.
1 1/2 IN.
59.94
(2.36)
115.82
(4.56)
Lineage Power 19
Data Sheet
April 2008 18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
Notes
Data Sheet
April 200818 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W
FC250F1 Power Module: dc-dc Converter;
April 2008
DS99-266EPS
World Wide Headquarters
Lineage Power Corporation
30 00 Skyline Drive, Mesquite, TX 75149, USA
+1-800-526-7819
(Outside U.S.A.: +1- 97 2-2 84 -2626)
www.lineagepower.com
e-mail: techsupport1@lineagepower.com
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Tel: +65 641 6 4283
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Lineage Power reserves the right to make changes to the product(s) or information contained herein without notice. No liability is assumed as a result of their use or
application. No rights under any patent accompany the sale of any such pr oduct(s) or information.
© 2008 Lineage Power Corporation, (Mesquite, Texas) All International Rights Reserved.
