Data Sheet
May 1998
FW250H1 and FW300H1 Power Modules:
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
The FW250H1 and FW300H1 Power Modules use advanced,
surface-mount technology and deliver high-quality, compact,
dc-dc conversion at an economical price.
Applications
■
Redundant and distributed power architectures
Options
■
Heat sink available for extended operation
Features
■
Size: 61.0 mm x 116.8 mm x 13.5 mm
(2.40 in. x 4.60 in. x 0.53 in.)
■
Wide input voltage range
■
High efficiency: 89% typical
■
Parallel operation with load sharing
■
Output voltage set-point adjustment (trim)
■
Thermal protection
■
Synchronization
■
Power good signal
■
Current monitor
■
Output overvoltage and overcurrent protection
■
Constant frequency
■
Case ground pin
■
Input-to-output isolation
■
Remote sense
■
Remote on/off
■
Short-circuit protection
■
Output overvoltage clamp
■
UL
* Recognized,
CSA
†
Certified, VDE Licensed
■
CE mark meets 73/23/EEC and 93/68/EEC
directives
‡
Description
The FW250H1 and FW300H1 Power Modules are dc-dc converters that operate ov er an input voltage range of
36 Vdc to 75 Vdc and provide a precisely regulated dc output. The outputs are fully isolated from the inputs,
allowing versatile polarity configurations and grounding connections. The modules have maximum power rat-
ings from 250 W to 300 W at a typical full-load efficiency of 89%.
Two or more modules ma y be paralleled with f orced load sharing f or redundant or enhanced pow er applications.
The package, which mounts on a printed-circuit board, accommodates a heat sink for high-temperature
applications.
*
UL
is a registered trademark of Underwriters Laboratories, Inc.
†
CSA
is a registered trademark of Canadian Standards Association.
‡This product is intended for integration into end-use equipment. All the required procedures for CE marking of end-use equipment should
be followed. (The CE mark is placed on selected products.)
2 Tyco Electronics Corp.
Data Sheet
May 1998
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
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; howev er, to achie ve 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) V
I
V
I, trans
—
—80
100 Vdc
Vdc
I/O Isolation Voltage — — 1500 V
Operating Case Temperature
(See Thermal Considerations section and
Figure 22.)
T
C
–40 100 °C
Storage Temperature T
stg
–55 125 °C
Parameter Symbol Min Typ Max Unit
Operating Input Voltage V
I
36 48 75 Vdc
Maximum Input Current (V
I
= 0 V to 75 V):
FW250H1
FW300H1 I
I, max
I
I, max
—
——
—12
12 A
A
Inrush Transient i
2
t — — 2.0 A
2
s
Input Reflected-ripple Current, Peak-to-peak
(5 Hz to 20 MHz, 12 µH source impedance;
see Figure 12.)
— — 10 — mAp-p
Input Ripple Rejection (120 Hz) — — 60 — dB
Tyco Electronics Corp. 3
Data Sheet
May 1998 dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Electrical Specifications
(continued)
Table 2. Output Specifications
Table 3. Isolation Specifications
Parameter Symbol Min Typ Max Unit
Output Voltage
(Over all operating input voltage, resistive load,
and temperature conditions until end of life; see
Figure 13 and Feature Descriptions.)
V
O
23.15 — 24.85 Vdc
Output Voltage Set Point
(V
I
= 48 V; I
O
= I
O, max
; T
C
= 25 °C) V
O, set
23.45 — 24.55 Vdc
Output Regulation:
Line (V
I
= 36 V to 75 V)
Load (I
O
= I
O, min
to I
O, max
)
Temperature (T
C
= –40 °C to +100 °C)
—
—
—
—
—
—
0.01
0.05
100
0.1
0.2
300
%
%
mV
Output Ripple and Noise Voltage
(See Figures 7, 8, and 14.):
RMS
Peak-to-peak (5 Hz to 20 MHz) —
——
——
—100
250 mVrms
mVp-p
Output Current
(At I
O
< I
O, min
, the modules may exceed output
ripple specifications.):
FW250H1
FW300H1 I
O
I
O
0.1
0.1 —
—10.4
12.5 A
A
Output Current-limit Inception
(V
O
= 90% of V
O , set
; see Feature Descriptions.) I
O, cli
103 — 130 % I
O, max
Output Short-circuit Current
(V
O
= 1.0 V; indefinite duration, no hiccup mode;
see Figures 3 and 4.)
— — — 150 % I
O, max
External Load Capacitance (electrolytic, total for
one unit or multiple paralleled units):
FW250H1
FW300H1 —
—330
330 —
—5,000
5,000 µF
µF
Efficiency (V
I
= 48 V; I
O
= I
O, max
; T
C
= 25 °C;
see Figures 5, 6, and 13.):
FW250H1
FW300H1
η
η
87
87 89
89 —
—%
%
Dynamic Response
(
∆
I
O
/
∆
t = 1 A/10 µs, V
I
= 48 V, T
C
= 25 °C; see
Figures 9 and 10.):
Load Change from I
O
= 50% to 75% of I
O, max
:
Peak Deviation
Settling Time (V
O
< 10% of peak deviation)
Load Change from I
O
= 50% to 25% of I
O, max
:
Peak Deviation
Settling Time (V
O
< 10% of peak deviation)
—
—
—
—
—
—
—
—
2
200
2
200
—
—
—
—
%V
O, set
µs
%V
O, set
µs
Parameter Min Typ Max Unit
Isolation Capacitance — 1700 — pF
Isolation Resistance 10 — — M
Ω
4 Tyco Electronics Corp.
Data Sheet
May 1998
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
General Specifications
Feature Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions. See Feature Descriptions for further information.
Parameter Min Typ Max Unit
Calculated MTBF (I
O
= 80% of I
O, max
; T
C
= 40 °C) 1,500,000 hours
Weight — — 200 (7) g (oz.)
Parameter Symbol Min Typ Max Unit
Remote On/Off Signal Interface
(V
I
= 0 V to 75 V; open collector or equivalent
compatible; signal referenced to V
I
(–) terminal; see
Figure 15 and Feature Descriptions.):
Logic Low—Module On
Logic High—Module Off
Logic Low:
At I
on/off
= 1.0 mA
At V
on/off
= 0.0 V
Logic High:
At I
on/off
= 0.0 µA
Leakage Current
Turn-on Time
(I
O
= 80% of I
O, max
; V
O
within ±1% of steady state)
Output Voltage Overshoot
V
on/off
I
on/off
V
on/off
I
on/off
—
—
0
—
—
—
—
—
—
—
—
—
30
0
1.2
1.0
15
50
50
5
V
mA
V
µA
ms
%V
O, set
Output Voltage Adjustment (See Feature Descriptions.):
Output Voltage Remote-sense Range
Output Voltage Set-point Adjustment Range (trim) —
——
60 —
—0.5
110 V
%V
O, nom
Output Overvoltage Protection (shutdown) — 29.5 — 34.0 V
Output Current Monitor (I
O
= I
O
,
max
, T
C
= 70 °C) I
O, mon
— 0.25 — V/A
Synchronization:
Clock Amplitude
Clock Pulse Width
Fan-out
Capture Frequency Range
—
—
—
—
4.00
0.4
—
425
—
—
—
—
5.00
—
1
575
V
µs
—
kHz
Overtemperature Shutdown (See Figure 22.) T
C
— 105 — °C
Current Share Accuracy — — 10 — %I
O, rated
Power Good Signal Interface
(See Feature Descriptions.):
Low Impedance—Module Operating
High Impedance—Module Off
R
pwr/good
I
pwr/good
R
pwr/good
V
pwr/good
—
—
1
—
—
—
—
—
100
1
—
40
Ω
mA
M
Ω
V
Tyco Electronics Corp. 5
Data Sheet
May 1998 dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Characteristic Curves
The following figures provide typical characteristics for the FW250H1 and FW300H1 power modules.
8-1698 (C)
Figure 1. T ypical FW250H1 Input Characteristics at
Room Temperature
8-1699 (C)
Figure 2. T ypical FW300H1 Input Characteristics at
Room Temperature
8-1700 (C)
Figure 3. Typical FW250H1 Output Characteristics
at Room Temperature
8-1701 (C)
Figure 4. Typical FW300H1 Output Characteristics
at Room Temperature
2
515 5565
0
INPUT VOLTAGE, V
I
(V)
3
5
1
10
0 35 4525 7510 20 30 40 50 60 70
7
4
6
9
8
I
O
= 10.4 A
I
O
= 5.2 A
I
O
= 1.0 A
TURN-OFF TURN-ON
INPUT CURRENT, I
I
(A)
10 20 30 40 50
0
6
INPUT VOLTAGE, VI
(
V
)
4
8
8
0
0
2
60 70
10
12
INPUT CURRENT, II (A)
IO = 12.5 A
IO = 6.25 A
IO = 1.25 A
4
2 101214
0
OUTPUT CURRENT, I
O
(A)
8
16
2
26
0 6 8413 57 911131516
22
12
18
24
6
14
10
20
V
I
= 75 V
OUTPUT VOLTAGE, V
O
(V)
V
I
= 55 V
V
I
= 36 V
2 4 6 8 10 12
0
15
OUTPUT CURRENT, I
O
(A)
10
20
1
8
0
5
14 16
25
OUTPUT VOLTAGE, V
O
(V)
V
I
= 75 V
V
I
= 55 V
V
I
= 36 V
66 Tyco Electronics Corp.
Data Sheet
May 1998
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Characteristic Curves
(continued)
8-1702 (C)
Figure 5. Typical FW250H1 Efficiency vs. Output
Current at Room Temperature
8-1703 (C)
Figure 6. Typical FW300H1 Efficiency vs. Output
Current at Room Temperature
82
1.0 2.0 6.0 7.0 8.0 9.0
80
OUTPUT CURRENT, I
O
(A)
83
85
81
10.00.0 4.0 5.03.0
87
84
86
90
88
89
EFFICIENCY, (%)
V
I
= 75 V
V
I
= 55 V
V
I
= 36 V
4 6 8 1210
80
86
OUTPUT CURRENT, I
O
(A)
84
83
85
88
02
87
82
81
89
90
EFFICIENCY, (%)
V
I
= 75 V
V
I
= 55 V
V
I
= 36 V
8-1704 (C)
Figure 7. Typical FW250H1 Output Ripple Voltage
at Room Temperature and 50 A Output
8-1705 (C)
Figure 8. Typical FW300H1 Output Ripple Voltage
at Room Temperature and 60 A Output
TIME, t (500 ns/div)
OUTPUT VOLTAGE, V
O
(V)
(10 mV/div)
V
I
= 48 V
TIME, t (500 ns/div)
OUTPUT VOLTAGE, V
O
(V)
(10 mV/div)
V
I
= 48 V
Tyco Electronics Corp. 7
Data Sheet
May 1998 dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Characteristic Curves
(continued)
8-1706 (C)
Figure 9. Typical FW250H1 Transient Response to
Step Decrease in Load from 50% to 25%
of Full Load at Room Temperature and
48 V Input (Waveform Averaged to
Eliminate Ripple Component.)
8-1707 (C)
Figure 10. Typical FW250H1 Transient Response to
Step Increase in Load from 50% to 75%
of Full Load at Room Temperature and
48 V Input (Waveform Averaged to
Eliminate Ripple Component.)
8-1709 (C)
Figure 11. Typical FW250H1 Start-Up Transient at
Room Temperature, 48 V Input, and Full
Load
TIME, t (50 µs/div)
OUTPUT VOLTAGE, V
O
(V)
(200 mV/div)
OUTPUT CURRENT, I
O
(A)
(2 A/div)
5.2
2.6
24
TIME, t (50 µs/div)
OUTPUT VOLTAGE, V
O
(V)
(200 mV/div)
OUTPUT CURRENT, I
O
(A)
(2 A/div)
24
8
5.2
TIME, t (10 ms/div)
OUTPUT VOLTAGE, V
O
(V)
(5 V/div)
24
0
0
REMOTE ON/OFF, V
ON/OFF
(V)
88 Tyco Electronics Corp.
Data Sheet
May 1998
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Test Configurations
8-203 (C).o
Note: Measure input reflected-ripple current with a simulated source
inductance (L
TEST
) of 12 µH. Capacitor C
S
offsets possible bat-
tery impedance. Measure current as shown above.
Figure 12. Input Reflected-Ripple Test Setup
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.
Figure 13. Output Voltage and Efficiency
Measurement Test Setup
8-513 (C).n
Note: Use a 0.1 µF ceramic capacitor and a 330 µF aluminum or
tantalum capacitor . The 330 µF capacitor is needed f or stability,
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 14. Peak-to-Peak Output Noise
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 12, a 100 µF
electrolytic capacitor (ESR < 0.3
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 saf ety extr a-low v oltage (SELV), one of
the following must be true:
■
All inputs are SELV and floating, with the output also
floating.
■
All inputs are SELV and grounded, with the output
also grounded.
■
Any non-SELV input must be provided with rein-
f orced insulation from an y other hazardous voltages ,
including the ac mains, and must have a SELV reli-
ability test performed on it in combination with the
converters. Inputs 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
tailout characteristics (output-current decrease or
increase). The unit operates normally once the output
current is brought back into its specified range.
TO OSCILLOSCOPE
12 µH VI(+)
VI(–)
BATTERY
LTEST
Cs 220 µF
ESR < 0.1 Ω
@ 20 °C, 100 kHz 100 µF
ESR < 0.3 Ω
@ 100 kHz
V
I
(–)
V
O
(+)
SENSE(+)
SENSE(–)
V
O
(–)
V
I
(+)
I
O
LOAD
CONTACT AND
DISTRIBUTION LOSSES
SUPPLY
I
I
CONTACT
RESISTANCE
ηVO+()
–
V
O
–
()[]
I
O
V
I
+
()
–
V
I
–
()[]
I
I
--------------------------------------------------
x
100=
V
O
(+)
V
O
(–)
1.0 µF RESISTIVE
LOAD
SCOPE
COPPER STRIP
330 µF
Tyco Electronics Corp. 9
Data Sheet
May 1998 dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Feature Descriptions
Remote On/Off
To turn the power module on and off , the user must
supply a s witch to control the v oltage betw een the on/off
terminal and the V
I
(–) terminal (V
on/off
). The s witch can be
an open collector or equivalent (see Figure 15). A logic
low is V
on/off
= 0 V to 1.2 V, during which the module is on.
The maximum I
on/off
during a logic low is 1 mA. The s witch
should maintain a logic-low v oltage while sinking 1 mA.
During a logic high, the maximum V
on/off
generated by
the power module is 15 V. The maximum allowable
leakage current of the switch at V
on/off
= 15 V is 50 µA.
If not using the remote on/off feature, short the
ON/OFF pin to V
I
(–).
8-580 (C).d
Figure 15. 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 giv en in the Feature Specifica-
tions table, i.e.:
[V
O
(+) – V
O
(–)] – [SENSE(+) – SENSE(–)]
≤
0.5 V
The voltage between the V
O
(+) and V
O
(–) terminals
must not exceed the minimum value indicated in the
output overvoltage shutdown 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 16.
If not using the remote-sense f eature to regulate the out-
put at the point of load, connect SENSE(+) to V
O
(+) and
SENSE(–) to V
O
(–) at the module.
8-651 (C).e
Figure 16. 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 (R
adj-down
), the output v oltage
set point (V
O , adj
) decreases (see Figure 17). The follow-
ing equation determines the required external-resistor
value to obtain a percentage output voltage change of
∆
%.
The test results for this configuration are displayed in
Figure 18. This figure applies to all output voltages.
With an external resistor connected between the TRIM
and SENSE(+) pins (R
adj-up
), the output voltage set
point (V
O, adj
) increases (see Figure 19).
The following equation determines the required exter-
nal-resistor value to obtain a percentage output v oltage
change of
∆
%.
The test results for this configuration are displayed in
Figure 20.
The voltage between the V
O
(+) and V
O
(–) 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 v oltage
due to remote-sense compensation and output voltage
set-point adjustment (trim). See Figure 16.
If not using the trim feature, leave the TRIM pin open.
+
Ion/off
–
Von/off
CASE
ON/OFF
VI(+)
VI(–)
SENSE(+)
SENSE(–)
VO(+)
VO(–)
V
O
(+)
SENSE(+)
SENSE(–)
V
O
(–)
V
I
(+)
V
I
(–)
I
O
LOAD
CONTACT AND
DISTRIBUTION LOSSES
SUPPLY I
I
CONTACT
RESISTANCE
Radj-down 205
∆%
----------2.255–
k
Ω
=
Radj-up VO, nom 1∆%
100
----------
+()1.225–()
1.225∆%
()
------------------------------------------------------------------------- 205 2.255–
kΩ=
1010 Tyco Electronics Corp.
Data Sheet
May 1998
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Feature Descriptions
(continued)
Output V oltage Set-Point Adjustment (T rim)
(continued)
8-748 (C).b
Figure 17. Circuit Configuration to Decrease
Output V oltage
8-1171 (C).g
Figure 18. Resistor Selection f or Decreased Output
Voltage
8-715 (C).b
Figure 19. Circuit Configuration to Increase
Output V oltage
8-1934 (C)
Figure 20. Resistor Selection for Increased Output
Voltage
Output Overvoltage Protection
The output voltage is monitored at the V
O
(+) and V
O
(–)
pins of the module. If the v oltage at these pins e xceeds
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 s or toggling the primary
referenced on/off signal for at least 1.0 s.
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
FW250H1, the V/A ratio is set at 250 mV/A
±
10% @
70
°
C case. At a full load current of 12.5 A, the voltage
on the CURRENT MON pin is 3.13 V. The current mon-
itor signal is referenced to the SENSE(–) pin on the
secondary and is supplied from a source impedance of
approximately 2 k
Ω
. 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.
VI(+)
VI(–)
ON/OFF
CASE
VO(+)
VO(–)
SENSE(+)
TRIM
SENSE(–) Radj-down
RLOAD
010203040
1M
PERCENT CHANGE IN OUTPUT VOLTAGE
(
∆%
)
100k
10k
1k
ADJUSTMENT RESISTOR VALUE (Ω)
VI(+)
VI(–)
ON/OFF
CASE
VO(+)
VO(–)
SENSE(+)
TRIM
SENSE(–)
Radj-up RLOAD
2468
100
1k
PERCENT CHANGE IN OUTPUT VOLTAGE
(
∆%
)
ADJUSTMENT RESISTOR VALUE (Ω)
100k
100
10k
Tyco Electronics Corp. 11
Data Sheet
May 1998 dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Feature Descriptions
(continued)
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/slav e configuration; that is, if one module f ails,
the other modules will continue to operate.
SYNC IN Pin
This pin can be connected either to an e xternal clock or
directly to the SYNC OUT pin of another FW250x or
FW300x module.
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 V
I
(–) pins of the modules must be
shorted together.
Unused SYNC IN pins should be tied to V
I
(–). 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 V
I
(–)
pin. The frequency of this signal will equal either the mod-
ule’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 Shutdown
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 s or toggling the primary referenced on/off
signal for at least 1.0 s.
Forced Load Sharing (Parallel Operation)
For either redundant operation or additional power
requirements, the po wer modules can be configured for
parallel operation with forced load sharing (see
Figure 21). 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 m ultiple units are used to de v elop
combined power in excess of the rated maximum, the
Schottky diodes are not needed.
Good layout techniques should be observed for noise
immunity. To implement forced load sharing, the follow-
ing connections must be made:
■
The parallel pins of all units must be connected
together. The paths of these connections should be
as direct as possible.
■
All 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 b us at the
same point and all SENSE(–) pins to the (–) side of
the pow er bus at the same point. Close pro ximity and
directness are necessary for good noise immunity.
When not using the parallel feature, leave the
PARALLEL pin open.
1212 Tyco Electronics Corp.
Data Sheet
May 1998
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Feature Descriptions
(continued)
Forced Load Sharing (Parallel Operation)
(continued)
8-581 (C)
Figure 21. 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 le vel must not e xceed 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 22.
8-1303 (C).a
Note: Top view, measurements shown in millimeters and (inches).
Pin locations are for reference only.
Figure 22. Case Temperature Measurement
Location
The temperature at this location should not exceed
100 °C . The maximum case temperature 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, refer to
the
Thermal Management for FC- and FW-Series 250
W—300 W Board-Mounted Power Modules
Technical
Note (TN96-009EPS).
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
(–)
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
Tyco Electronics Corp. 13
Data Sheet
May 1998 dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Thermal Considerations (continued)
Heat Transfer Without Heat Sinks
Derating curves for forced-air cooling without a heat
sink are shown in Figures 23 and 24. These curves can
be used to determine the appropriate airflow f or a giv en
set of operating conditions. F or 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 23. Con vection P ower Derating with No Heat
Sink; Airflow Along Width (Transverse)
8-1314 (C)
Figure 24. Con vection P ower Derating with No Heat
Sink; Airflow Along Length
(Longitudinal)
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 the 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.-lbs.).
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 22. Case-to-ambient thermal resis-
tance vs. airflow for various heat sink configurations is
shown in Figure 25 and Figure 26. These curves were
obtained by experimental testing of heat sinks, which
are offered in the product catalog.
8-1321 (C)
Figure 25. Case-to-Ambient Thermal Resistance
Curves; T ransverse Orientation
010203040 100
0
40
60
70
LOCAL AMBIENT TEMPERATURE, T
A
(°C)
POWER DISSIPATION, P
D
(W)
30
20
10
9080706050
50
0.1 m/s (20 ft./min.)
NAT. CONV.
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.)
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.
θca ∆TC max,
PD
---------------------TCTA–()
PD
------------------------
==
0.5
(100) 1.0
(200) 1.5
(300) 2.0
(400) 2.5
(500) 3.0
(600)
AIR VELOCITY, m/s
(
ft./min.
)
0
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
CASE-TO-AMBIENT THERMAL
RESISTANCE, R
CA
(°C/W)
1414 Tyco Electronics Corp.
Data Sheet
May 1998
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Thermal Considerations (continued)
Heat Transfer with Heat Sinks (continued)
8-1320 (C)
Figure 26. 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 25 and
26 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. Fig-
ures 27 and 28 show typical heat dissipation for a
range of output currents and three voltages for the
FW250H1 and FW300H1.
8-1711 (C)
Figure 27. FW250H1 Power Dissipation vs. Output
Current
8-1712 (C)
Figure 28. FW300H1 Power Dissipation vs. Output
Current
0 0.5
(100) 1.0
(200) 1.5
(300) 2.0
(400) 2.5
(500) 3.0
(600)
AIR VELOCITY, m/s
(
ft./min.
)
0.0
0.5
3.0
3.5
4.0
4.5
2.5
2.0
1.0
CASE-TO-AMBIENT THERMAL
RESISTANCE, R
CA
(°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
1.5
10
POWER DISSIPATION, P
D
(W)
1.0 2.0 6.0 7.0 8.0 9.0
0
OUTPUT CURRENT, I
O
(A)
15
25
5
10.00.0 4.0 5.03.0
20
30
35
V
I
= 75 V
V
I
= 55 V
V
I
= 36 V
4 6 8 1210
0
30
OUTPUT CURRENT, IO (A)
20
15
25
40
2
35
10
5
45
50
0
VI = 75 V
VI = 55 V
VI = 36 V
POWER DISSIPATION, PD (W)
Tyco Electronics Corp. 15
Data Sheet
May 1998 dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
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 FW250H1
module is operating at nominal line and an output cur-
rent of 10 A, maximum ambient air temperature of
40 °C, and the heat sink is 0.5 inch.
Solution
Given: VI = 54 V
IO = 10 A
TA = 40 °C
TC = 85 °C
Heat sink = 0.5 inch.
Determine PD by using Figure 27:
PD = 28 W
Then solve the following equation:
Use Figures 25 and 26 to determine air velocity for the
0.5 inch heat sink. The minimum airflow necessary for
the FW250H1 module depends on heat sink fin orienta-
tion and is shown below:
■1.25 m/s (250 ft./min.) (oriented along width)
■1.5 m/s (300 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 29.
8-1304 (C)
Figure 29. 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 provides
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–()
28
------------------------
=
θca 1.61 °C/W=
PDTCTSTA
cs sa
θsa TCTA–()
PD
-------------------------θcs–=
16 Tyco Electronics Corp.
Data Sheet
May 1998
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
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)
* Side label includes Tyco 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 PLCS
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 PLCS
(VOUT–, VOUT+, VIN–, VIN+)
1.02 ± 0.05 (0.040 ± 0.002) DIA
SOLDER-PLATED BRASS
9 PLCS
SIDE LABEL*
116.8 (4.60)
61.0
(2.40)
Tyco Electronics Corp. 17
Data Sheet
May 1998 dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Recommended Hole Pattern
Component-side footprint.
Dimensions are in millimeters and (inches).
8-1650 (C)
Ordering Information
Input V oltage Output V oltage Output Power Device Code Comcode
48 V 24 V 250 W FW250H1 108026840
48 V 24 V 300 W FW300H1 107430324
5.1 (0.20)
10.16
(0.400)
MOUNTING INSERTS
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)
18 Tyco Electronics Corp.
Data Sheet
May 1998
dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Notes
Tyco Electronics Corp. 19
Data Sheet
May 1998 dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Notes
Data Sheet
March 27, 2001dc-dc Converters; 36 to 75 Vdc Input, 24 Vdc Output; 250 W to 300 W
FW250H1 and FW300H1 Power Modules:
Printed on
Recycled Paper
Tyco Electronics Power Systems, Inc.
3000 Skyline Drive, Mesquite, TX 75149, USA
+1-800-526-7819 FAX: +1-888-315-5182
(Outside U.S.A.: +1-972-284-2626, FAX: +1-972-284-2900
http://power.tycoeleectronics.com
Tyco Electronics Corportation 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 product(s) or information.
© 2001 Tyco Electronics Corporation, Harrisburg, PA. All International Rights Reserved.
Printed in U.S.A.
May 1998
DS97-516EPS
