Data Sheet
March 2000
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
The FW250R1 and FW300R1 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
■
Computer equipment
■
Communications equipment
Options
■
Heat sinks 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: 90.5% typical
■
Parallel operation with load sharing
■
Output voltage set-point adjustment (trim)
■
Overtemperature protection
■
Synchronization
■
Power good signal
■
Output current monitor
■
Output overvoltage and overcurrent protection
■
Constant frequency
■
Case ground pin
■
Input-to-output isolation
■
Remote sense
■
Remote on/off
■
ISO
* 9001 Certified manufacturing facilities
■
UL
†
1950
Recognized,
CSA
‡
C22.2 No. 950-95
Certified, and
VDE
§
0805 (EN60950, IEC950)
Licensed
■
CE mark meets 73/23/EEC and 93/68/EEC direc-
tives**
Description
The FW250R1 and FW300R1 Power Modules are dc-dc converters that operate over 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 90.5%.
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.
*
ISO
is a registered trademark of the International Organization for Standardization.
†
UL
is a registered trademark of Underwriters Laboratories, Inc.
‡
CSA
is a registered trademark of Canadian Standards Assn.
§
VDE
is a trademark of Verband Deutscher Elektrotechniker e.V.
** This product is intended f or integr ation 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 Lucent Technologies Inc.
Data Sheet
March 2000
36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 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; howe ver , 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 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 (for 1 minute) — — 1500 Vdc
Operating Case Temperature
(See Thermal Considerations section and
Figure 18.)
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):
FW250R1
FW300R1 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 8.)
I
I
— 10 — mAp-p
Input Ripple Rejection (120 Hz) — — 60 — dB
Lucent Technologies Inc. 3
Data Sheet
March 2000 36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Electrical Specifications
(continued)
Table 2. Output Specifications
* Consult your sales representative or the factory.
† These are manufacturing test limits. In some situations, results may differ.
Parameter Symbol Min Typ Max Unit
Output Voltage Set Point
(V
I
= 48 V; I
O
= I
O, max
; T
C
= 25 °C) V
O, set
27.45 28.0 28.55 Vdc
Output Voltage
(Over all operating input voltage, resistive load,
and temperature conditions until end of life; see
Figure 10 and Feature Descriptions.)
V
O
27.16 — 28.84 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
%V
O
%V
O
mV
Output Ripple and Noise Voltage
(See Figures 4 and 9.):
RMS
Peak-to-peak (5 Hz to 20 MHz) —
——
——
—50
200 mVrms
mVp-p
External Load Capacitance:
FW250R1
FW300R1 —
—330
330 —
—*
*µF
µF
Output Current
(At I
O
< I
O, min
, the modules may exceed output
ripple specifications.):
FW250R1
FW300R1 I
O
I
O
0.3
0.3 —
—9
10.7 A
A
Output Current-limit Inception
(V
O
= 90% of V
O , set
; see Feature Descriptions.) I
O, cli
— — 130
†
%I
O, max
Output Short-circuit Current
(V
O
= 1.0 V; indefinite duration, no hiccup mode;
see Figure 2.)
— — — 150 %I
O, max
Efficiency (V
I
= 48 V; I
O
= I
O, max
; T
C
= 25 °C;
see Figures 3 and 10.):
FW250R1
FW300R1
η
η
—
—90.5
90.5 —
—%
%
Switching Frequency — — 475 — kHz
Dynamic Response
(
∆
I
O
/
∆
t = 1 A/10 µs, V
I
= 48 V, T
C
= 25 °C; tested
with a 330 µF aluminum and a 1.0 µF ceramic
capacitor across the load; see Figures 5 and 6.):
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)
—
—
—
—
—
—
—
—
250
200
250
200
—
—
—
—
mV
µs
mV
µs
4 Lucent Technologies Inc.
Data Sheet
March 2000
36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Electrical Specifications
(continued)
Table 3. Isolation Specifications
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.
Table 4. Feature Specifications
* These are manufacturing test limits. In some situations, results may differ.
Parameter Min Typ Max Unit
Isolation Capacitance — 1700 — pF
Isolation Resistance 10 — — M
Ω
Parameter Min Typ Max Unit
Calculated MTBF (I
O
= 80% of I
O, max
; T
C
= 40 °C) 1,587,000 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 11 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
—
—
—
—
—
—
—
—
—
100
0
1.2
1.0
15
50
150
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
102 V
%V
O, nom
Output Overvoltage Protection — 30.9* — 37.0* V
Output Current Monitor (I
O
= I
O,
max
, T
C = 70 °C) IO, mon — 0.37 — V/A
Lucent Technologies Inc. 5
Data Sheet
March 2000 36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Feature Specifications (continued)
Table 4. Feature Specifications (continued)
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
Lucent Technologies
Board-Mounted Power Modules Soldering and Cleaning
Application Note (AP97-021EPS).
Parameter Symbol Min Typ Max Unit
Synchronization:
Clock Amplitude
Clock Pulse Width
Fan-out
Capture Frequency Range
—
—
—
—
4.00
0.4
—
425
—
—
—
—
5.00
—
1
575
V
µs
—
kHz
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
Ω
mA
MΩ
V
66 Lucent Technologies Inc.
Data Sheet
March 200036 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Characteristic Curves
The following figures provide typical characteristics for the power modules.
8-1713 (C)
Figure 1. T ypical FW250R1 Input Characteristics at
Room Temperature
8-1714 (C)
Figure 2. Typical FW250R1 Output Characteristics
at Room Temperature
8-1715 (C)
Figure 3. Typical FW250R1 Efficiency vs. Output
Current at Room Temperature
8-1716 (C)
Note: See figure 9 for test conditions.
Figure 4. Typical FW250R1 Output Ripple Voltage
at Room Temperature, and Full Load
Output
2
816 48
56 64
0
INPUT VOLTAGE, V
I
(V)
3
5
1
9
0 32 40244 12202836 44 52 60 6872
7
4
6
8
INPUT CURRENT, I
I
(A)
I
O
= 8.93 A
I
O
= 4.50 A
I
O
= 0.45 A
VOLTAGE
TURN-OFF VOLTAGE
TURN-ON
OUPUT VOLTAGE, V
O
(V)
12 6789
0
22
OUTPUT CURRENT, I
O
(A)
12
8
18
30
100
26
4
4 53
14
20
10
6
16
28
24
2
11 12
V
I
= 75 V
V
I
= 54 V
V
I
= 36 V
EFFICIENCY, η (%)
3789
78
89
OUTPUT CURRENT, I
O
(A)
84
82
87
92
0
80
1 2
85
88
83
81
86
91
90
79
456
EFFICIENCY, η (%)
V
I
= 36 V
V
I
= 54 V
V
I
= 75 V
TIME, t (500 ns/div)
OUTPUT VOLTAGE, V
O
(V)
(10 mV/div)
V
I
= 72 V
V
I
= 48 V
V
I
= 36 V
Lucent Technologies Inc. 7
Data Sheet
March 2000 36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Characteristic Curves (continued)
8-1718 (C)
Note: Tested with a 330 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
Figure 5. Typical FW250R1 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.)
8-1719 (C)
Note: Tested with a 330 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
Figure 6. Typical FW250R1 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.)
8-1722 (C)
Note: Tested with a 330 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
Figure 7. Typical FW250R1 Start-Up Transient at
Room Temperature, 48 V Input, and Full
Load
TIME, t (50 µs/div)
4.5
OUTPUT VOLTAGE, V
O
(V)
(200 mV/div
)
OUTPUT CURRENT, I
O
(V)
(2 A/div)
2.25
0.0
28.0
TIME, t (50 µs/div)
4.5
6.75
OUTPUT VOLTAGE, V
O
(V)
(200 mV/div
)
OUTPUT CURRENT, I
O
(A)
(2 A/div)
0.0
28.0
TIME, t (10 ms
/div)
0
28
OUTPUT VOLTAGE, V
O
(V)
(5 V/div)
0
REMOTE ON/OFF, V
ON/OFF
(V)
88 Lucent Technologies Inc.
Data Sheet
March 200036 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Test Configurations
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
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 for 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 9. Peak-to-Peak Output Noise
Measurement 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 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 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
C22.2 No. 950-95, and
VDE
0805
(EN60950, IEC950).
If the input source is non-SELV (ELV or a hazardous
voltage greater than 60 Vdc and less than or equal to
75 Vdc), f or the module’s output to be considered meet-
ing the requirements of safety extra-low voltage
(SELV), all of the following must be true:
■The input source is to be provided with reinforced
insulation from any hazardous v oltages, including the
ac mains.
■One VI pin and one V O pin are to be grounded or both
the input and output pins are to be kept floating.
■The input pins of the module are not operator acces-
sible.
■Another SELV reliability test is conducted on the
whole system, as required by the saf ety agencies, on
the combination of supply source and the subject
module to verify that under a single fault, hazardous
voltages do not appear at the module’s output.
Note: Do not ground either of the input pins of the
module without grounding one of the output pins.
This may allow a non-SELV voltage to appear
between the output pin and ground.
The power module has extra-low v oltage (ELV) outputs
when all inputs are ELV.
The input to these units is to be provided with a maxi-
mum 20 A normal-blow fuse in the ungrounded lead.
TO OSCILLOSCOPE
12 µH V
I
(+)
V
I
(–)
BATTERY
L
TEST
Cs 220 µF
ESR < 0.1 Ω
@ 20 °C, 100 kHz 100 µF
ESR < 0.3 Ω
@ 100 kHz
V
O
(+)
V
O
(–)
1.0 µF RESISTIVE
LOAD
SCOPE
COPPER STRIP
330 µF
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 %=
Lucent Technologies Inc. 9
Data Sheet
March 2000 36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
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.
Remote On/Off
To turn the power module on and off , the user must
supply a s witch to control the v oltage between the on/off
terminal and the V
I
(–) terminal (V
on/off
). The s witch can be
an open collector or equivalent (see Figure 11). 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 switch
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 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.:
[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 12.
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.
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.
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.
+
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
1010 Lucent Technologies Inc.
Data Sheet
March 2000
36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Feature Descriptions
(continued)
Output V oltage Set-Point Adjustment (T rim)
(continued)
With an external resistor between the TRIM and
SENSE(–) pins (R
adj-down
), the output voltage set point
(V
O,
adj
) decreases (see Figure 13). The following equa-
tion determines the required external-resistor value to
obtain a percentage output voltage change of
∆
%.
The test results for this configuration are displayed in
Figure 14. This figure applies to all output voltages.
With an e xternal resistor connected between the TRIM
and SENSE(+) pins (R
adj-up
), the output voltage set
point (V
O,
adj
) increases (see Figure 15).
Note:
The output voltage of this module may be
increased to a maximum of 0.5 V. The 0.5 V is
the combination of both the remote sense and
the output voltage set-point adjustment (trim).
Do not exceed 28.5 V between the V
O
(+) and
V
O
(–) terminals.
The following equation determines the required exter-
nal-resistor value to obtain a percentage output v oltage
change of
∆
%.
Only trim up to 0.5 V maximum. See note above.
The test results for this configuration are displayed in
Figure 16.
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.
8-748 (C).b
Figure 13. Circuit Configuration to Decrease
Output V oltage
8-1171 (C).g
Figure 14. Resistor Selection for Decreased Output
Voltage
8-715 (C).b
Figure 15. Circuit Configuration to Increase
Output V oltage
Radj-down 205
∆%
----------2.255–
k
Ω
=
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
Lucent Technologies Inc. 11
Data Sheet
March 2000 36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Feature Descriptions
(continued)
Output V oltage Set-Point Adjustment (T rim)
(continued)
8-2052 (C)
Figure 16. 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 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
FW250R1, the V/A ratio is set at 370 mV/A
±
10% @
70
°
C case. At a full load current of 9 A, the voltage on
the CURRENT MON pin is 3.33 V. The current monitor
signal is referenced to the SENSE(–) pin on the sec-
ondary and is supplied from a source impedance of
approximately 2 k
Ω
. It is recommended that the
CURRENT 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
CURRENT MON pin with an external source will
detrimentally 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/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.
0.4 1.2 1.6
1M
PERCENT CHANGE IN OUTPUT VOLTAGE
(
∆%
)
ADJUSTMENT RESISTOR VALUE (Ω)
100M
2
0
10M
0.8
1212 Lucent Technologies Inc.
Data Sheet
March 2000
36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Feature Descriptions
(continued)
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 po wer 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.
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 power b us 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.
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 M
Ω
) 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.
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
(–)
Lucent Technologies Inc. 13
Data Sheet
March 2000 36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
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.
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
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, ref er to
the Lucent Technologies
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. 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 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
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
010203040 100
0
40
60
70
LOCAL AMBIENT TEMPERATURE, TA (°C)
POWER DISSIPATION, PD (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, TA (°C)
POWER DISSIPATION, PD (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.
1414 Lucent Technologies Inc.
Data Sheet
March 2000
36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Thermal Considerations
(continued)
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.-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 (
θ
ca) is defined as the maximum
case temperature rise (
∆
T
C, max
) divided by the module
power dissipation (P
D
):
The location to measure case temperature (T
C
) 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.
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 FW250R1.
8-1723 (C)
Figure 23. FW250R1 Power Dissipation vs. Output
Current at 25 °C
θca ∆TC max,
PD
---------------------TCTA–()
PD
------------------------
==
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
CASE-TO-AMBIENT THERMAL
RESISTANCE, θ
CA
(°C/W)
1.5
AIR VELOCITY, m/s (ft./min.)
12 6789
0
22
OUTPUT CURRENT, I
O
(A)
12
8
18
30
0
26
4
4 53
14
20
10
6
16
28
24
2
POWER DISSPATION, P
D
(V)
V
I
= 54 V
V
I
= 75 V
V
I
= 36 V
Lucent Technologies Inc. 15
Data Sheet
March 2000 36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Thermal Considerations
(continued)
Heat Transfer with Heat Sinks
(continued)
8-3127 (F)
Figure 24. FW300R1 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 FW250R1
module is operating at V
I
= 54 V and an output current
of 9 A, maximum ambient air temperature of 40 °C, and
the heat sink is 1/2 inch.
Solution
Given: V
I
= 54 V
I
O
= 9 A
T
A
= 40 °C
T
C
= 85 °C
Heat sink = 1/2 inch
Determine P
D
by using Figure 23:
P
D
= 26 W
Then solve the following equation:
Use Figures 21 and 22 to determine air velocity for the
1/2 inch heat sink. The minimum airflow necessary for
the FW250R1 module depends on heat sink fin orienta-
tion and is shown below:
■
1.1 m/s (220 ft./min.) (oriented along width)
■
1.3 m/s (260 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 (
θ
cs) and
sink-to-ambient (
θ
sa) as shown in Figure 25.
8-1304 (C)
Figure 25. Resistance from Case-to-Sink and Sink-
to-Ambient
For a managed interface using thermal grease or foils,
a value of
θ
cs = 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.
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).
0OUTPUT CURRENT, IO (A)
POWER DISSIPATION, PD (W)
246810
30
25
20
15
10
5
013579
35
VI = 72 V
VI = 54 V
VI = 36 V
θca TCTA–()
PD
------------------------
=
θca 85 40–()
26
------------------------
=
θca 1.73 °C/W=
PDTCTSTA
cs sa
θsa TCTA–()
PD
-------------------------θcs–=
16 Lucent Technologies Inc.
Data Sheet
March 2000
36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 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.)
8-1650 (C)
* Side label includes Lucent logo, 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)
Lucent Technologies Inc. 17
Data Sheet
March 2000 36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Recommended Hole Pattern
Component-side footprint.
Dimensions are in millimeters and (inches).
8-1650 (C)
Ordering Information
Table 5. Device Codes
Input V oltage Output V oltage Output Power Device Code Comcode
48 V 28 V 250 W FW250R1 107679029
48 V 28 V 300 W FW300R1 107430332
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)
1818 Lucent Technologies Inc.
Data Sheet
March 200036 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Ordering Information (continued)
Table 6. Device Accessories
Dimension are in millimeters and (inches).
8-2830 (C)
Figure 26. Longitudinal Heat Sink
8-2831 (C)
Figure 27. 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)
Lucent Technologies Inc. 19
Data Sheet
March 2000 36 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Notes
Data Sheet
March 200036 Vdc to 75 Vdc Input, 28 Vdc Output; 250 W to 300 W
FW250R1 and FW300R1 Power Modules: dc-dc Converters:
Lucent Technologies Inc. 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.
Copyright © 2000 Lucent Technologies Inc.
All Rights Reserved
Printed in U.S.A.
March 2000
DS99-324EPS (Replaces DS97-515EPS) Printed On
Recycled Paper
For additional information, contact your Lucent Technologies Account Manager or the following:
POWER SYSTEMS UNIT: Network Products Group, Lucent Technologies Inc., 3000 Skyline Drive, Mesquite, TX 75149, USA
+1-800-526-7819 (Outside U.S.A.: +1-972-284-2626, FAX +1-888-315-5182) (product-related questions or technical assistance)
INTERNET: http://www.lucent.com/networks/power
E-MAIL: techsupport1@lucent.com
ASIA PACIFIC: Lucent Technologies Singapore Pte. Ltd., 750D Chai Chee Road #07-06, Chai Chee Industrial Park, Singapore 469004
Tel. (65) 240 8041, FAX (65) 240 8438
CHINA: Lucent Technologies (China) Co. Ltd., SCITECH Place No. 22 Jian Guo Man Wai Avenue, Beijing 100004, PRC
Tel. (86) 10-6522 5566 ext. 4187, FAX (86) 10-6512 3694
JAPAN: Lucent Technologies Japan Ltd., Mori Building No. 21, 4-33, Roppongi 1-chome, Minato-ku, Tokyo 106-8508, Japan
Tel. (81) 3 5561 5831, FAX (81) 3 5561 1616
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Tel. +1-305-569-4722, FAX +1-305-569-3820
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