Data Sheet
March 2000
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Features
The FW250B1 and FW300B1 Power Modules use advanced,
surface-mount technology and deliver high-quality, compact,
dc-dc conversion at an economical price.
Applications
■
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: 87% 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
■
Remote sense
■
Redundant and distributed power architectures
■
Remote on/off
■
Computer equipment
■
Constant frequency
■
Communications equipment
■
Case ground pin
■
Input-to-output isolation
Options
■
■
■
Heat sinks available for extended operation
■
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 directives**
Description
The FW250B1 and FW300B1 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 ratings from 250 W to 300 W at a typical full-load efficiency of 87%.
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 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 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.)
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are absolute stress ratings only. Functional operation of the device 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
Input Voltage:
Continuous
Transient (100 ms)
I/O Isolation Voltage (for 1 minute)
Operating Case Temperature
(See Thermal Considerations section and
Figure 18.)
Storage Temperature
Symbol
Min
Max
Unit
VI
VI, trans
—
TC
—
—
—
–40
80
100
1500
100
Vdc
V
Vdc
°C
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
Operating Input Voltage
Maximum Input Current (VI = 0 V to 75 V):
FW250B1
FW300B1
Inrush Transient
Input Reflected-ripple Current, Peak-to-peak
(5 Hz to 20 MHz, 12 µH source impedance;
see Figure 8.)
Input Ripple Rejection (120 Hz)
Symbol
VI
Min
36
Typ
48
Max
75
Unit
Vdc
II, max
II, max
i2t
II
—
—
—
—
—
—
—
10
10
12
2.0
—
A
A
A2s
mAp-p
—
—
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 fusing 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 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.
2
Lucent Technologies Inc.
Data Sheet
March 2000
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Electrical Specifications (continued)
Table 2. Output Specifications
Parameter
Output Voltage Set Point
(VI = 48 V; IO = IO, max; TC = 25 °C)
Output Voltage
(Over all operating input voltage, resistive load,
and temperature conditions until end of life; see
Figure 10 and Feature Descriptions.)
Output Regulation:
Line (VI = 36 V to 75 V)
Load (IO = IO, min to IO, max)
Temperature (TC = –40 °C to +100 °C)
Output Ripple and Noise Voltage
(See Figures 4 and 9.):
RMS
Peak-to-peak (5 Hz to 20 MHz)
External Load Capacitance:
FW250B1
FW300B1
Output Current
(At IO < IO, min, the modules may exceed output
ripple specifications.):
FW250B1
FW300B1
Output Current-limit Inception
(VO = 90% of VO, set; see Feature Descriptions.)
Output Short-circuit Current
(VO = 1.0 V; indefinite duration, no hiccup mode;
see Figure 2.)
Efficiency (VI = 48 V; IO = IO, max; TC = 25 °C;
see Figures 3 and 10.):
FW250B1
FW300B1
Switching Frequency
Dynamic Response
(∆IO/∆t = 1 A/10 µs, VI = 48 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)
Symbol
VO, set
Min
11.82
Typ
12.0
Max
12.18
Unit
Vdc
VO
11.6
—
12.4
Vdc
—
—
—
—
—
—
0.01
0.05
50
0.1
0.2
100
%VO
%VO
mV
—
—
—
—
—
—
50
150
mVrms
mVp-p
—
—
0
0
—
—
*
*
µF
µF
IO
IO
—
—
—
20.8
25
130†
A
A
IO, cli
0.3
0.3
103
%IO, max
—
—
—
150
%IO, max
η
η
—
—
—
—
87
87
475
—
—
—
%
%
kHz
—
—
—
—
2
200
—
—
%VO, set
µs
—
—
—
—
2
200
—
—
%VO, set
µs
* Consult your sales representative or the factory.
† These are manufacturing test limits. In some situations, results may differ.
Lucent Technologies Inc.
3
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
Feature Specifications (continued)
Table 3. Isolation Specifications
Parameter
Isolation Capacitance
Isolation Resistance
Min
—
10
Typ
1700
—
Max
—
—
Unit
pF
MΩ
Min
Typ
1,500,000
—
Max
Unit
hours
g (oz.)
General Specifications
Parameter
Calculated MTBF (IO = 80% of IO, max; TC = 40 °C)
Weight
—
200 (7)
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
Remote On/Off Signal Interface
(VI = 0 V to 75 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
Output Voltage Adjustment (See Feature Descriptions.):
Output Voltage Remote-sense Range
Output Voltage Set-point Adjustment Range (trim)
Output Overvoltage Protection
Output Current Monitor (IO = IO, max, TC = 70 °C)
Symbol
Min
Typ
Max
Unit
Von/off
Ion/off
0
—
—
—
1.2
1.0
V
mA
Von/off
Ion/off
—
—
—
—
—
—
30
15
50
50
V
µA
ms
—
—
0
5
%VO, set
—
—
—
—
60
13.5*
—
—
—
—
0.18
1.2
110
16.0*
—
V
%VO, nom
V
V/A
IO, mon
* These are manufacturing test limits. In some situations, results may differ.
4
Lucent Technologies Inc.
Data Sheet
March 2000
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Feature Specifications (continued)
Table 4. Feature Specifications (continued)
Parameter
Synchronization:
Clock Amplitude
Clock Pulse Width
Fan-out
Capture Frequency Range
Overtemperature Protection
(See Figure 18.)
Forced Load Share Accuracy
Power Good Signal Interface
(See Feature Descriptions.):
Low Impedance—Module Operating
High Impedance—Module Off
Symbol
Min
Typ
Max
Unit
—
—
—
—
TC
4.00
0.4
—
425
—
—
—
—
—
105
5.00
—
1
575
—
V
µs
—
kHz
°C
—
—
10
—
%IO, rated
Rpwr/good
Ipwr/good
Rpwr/good
Vpwr/good
—
—
1
—
—
—
—
—
100
1
—
40
Ω
mA
MΩ
V
Solder, Cleaning, and Drying Considerations
Post solder cleaning is usually the final circuit-board assembly process prior to electrical testing. The result of inadequate 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
the Board-Mounted Power Modules Soldering and Cleaning Application Note (AP97-021EPS).
Lucent Technologies Inc.
5
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
Characteristic Curves
The following figures provide typical characteristics for the power modules.
12
11
IO = 25 A
(%)
9
8
7
EFFICIENCY,
INPUT CURRENT, II (A)
10
6
5
IO = 12.5 A
4
3
2
IO = 1.25 A
1
0
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
INPUT VOLTAGE, VI (V)
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
VI = 36 V
VI = 54 V
VI = 75 V
0
2
4
6
8
10
12
14 16
18
20 22
24
OUTPUT CURRENT, IO (A)
8-1727 (C)
8-1725 (C)
Figure 1. Typical FW300B1 Input Characteristics at
Room Temperature
Figure 3. Typical FW300B1 Efficiency vs. Output
Current at Room Temperature
14
10
8
6
4
VI = 36 V
VI = 48 V
VI = 75 V
2
0
0
5
10
15
20
25
30
35
OUTPUT VOLTAGE, VO (V)
(10 mV/div)
OUTPUT VOLTAGE, VO (V)
12
VI = 48 V
OUTPUT CURRENT, IO (A)
8-2221 (C)
Figure 2. Typical FW300B1 Output Characteristics
at Room Temperature
TIME, t (500 ns/div)
8-1728 (C)
Note: See figure 9 for test conditions.
Figure 4. Typical FW300B1 Output Ripple Voltage
at Room Temperature and 60 A Output
6
Lucent Technologies Inc.
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
OUTPUT VOLTAGE, VO (V) REMOTE ON/OFF, VON/OFF(V)
(5 V/div)
OUTPUT CURRENT, IO (A)
(5 A/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
Characteristic Curves (continued)
12
12.5
6.25
0.0
TIME, t (5 ms/div)
TIME, t (500 µs/div)
8-1731 (C)
8-1729 (C)
Note: Tested with a 10 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
OUTPUT CURRENT, IO (A)
(5 A/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
Figure 5. Typical FW300B1 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.)
Note: Tested with a 10 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
Figure 7. Typical FW300B1 Start-Up Transient at
Room Temperature, 48 V Input, and Full
Load
12
18.75
12.5
0.0
TIME, t (500 µs/div)
8-1730 (C)
Note: Tested with a 10 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
Figure 6. Typical FW300B1 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.)
Lucent Technologies Inc.
7
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
Design Considerations
Test Configurations
Input Source Impedance
TO OSCILLOSCOPE
LTEST
VI(+)
12 µH
Cs 220 µF
ESR < 0.1 Ω
@ 20 °C, 100 kHz
BATTERY
100 µF
ESR < 0.3 Ω
@ 100 kHz
VI(–)
The power module should be connected to a low
ac-impedance input source. Highly inductive source
impedances can affect the stability of the power module. 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 stability of the unit. For other highly inductive source
impedances, consult the factory for further application
guidelines.
8-203 (C).o
Note: Measure input reflected-ripple current with a simulated source
inductance (LTEST) of 12 µH. Capacitor CS offsets possible battery impedance. Measure current as shown above.
Figure 8. Input Reflected-Ripple Test Setup
COPPER STRIP
V O (+)
1.0 µF
RESISTIVE
LOAD
10.0 µF SCOPE
V O (–)
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
SENSE(+)
SENSE(–)
SUPPLY
VI(+)
VO(+)
VI(–)
VO(–)
IO
II
CONTACT
RESISTANCE
LOAD
CONTACT AND
DISTRIBUTION LOSSES
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.
[VO(+) – VO(–)]IO
η = -------------------------------------------------- x 100
[VI(+) – VI(–)]II
%
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., UL1950, 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), for the module’s output to be considered meeting 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 voltages, including the
ac mains.
■
One VI pin and one VO 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 accessible.
■
Another SELV reliability test is conducted on the
whole system, as required by the safety 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 voltage (ELV) outputs
when all inputs are ELV.
The input to these units is to be provided with a maximum 20 A normal-blow fuse in the ungrounded lead.
Figure 10. Output Voltage and Efficiency
Measurement Test Setup
8
Lucent Technologies Inc.
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
Feature Descriptions
Remote Sense
Overcurrent Protection
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 output voltage sense range given in the Feature Specifications table, i.e.:
To provide protection in a fault (output overload) condition, the unit is equipped with internal current-limiting
circuitry and can endure current limiting for an unlimited 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 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(–).
SENSE(+)
CASE
SENSE(–)
Ion/off
[VO(+) – VO(–)] – [SENSE(+) – SENSE(–)] ≤ 1.2 V
The voltage between the VO(+) and VO(–) 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 feature to regulate the output 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.
VO(+)
ON/OFF
+
Von/off
–
SENSE(+)
VI(+)
VO(–)
SENSE(–)
VI(–)
8-580 (C).d
Figure 11. Remote On/Off Implementation
SUPPLY
VI(+)
VO(+)
VI(–)
VO(–)
IO
II
CONTACT
RESISTANCE
LOAD
CONTACT AND
DISTRIBUTION LOSSES
8-651 (C).e
Figure 12. Effective Circuit Configuration for
Single-Module Remote-Sense Operation
Lucent Technologies Inc.
9
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Feature Descriptions (continued)
Output Voltage Set-Point Adjustment (Trim)
be taken to ensure that the maximum output power of
the module remains at or below the maximum rated
power.
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.
VI(+)
CASE
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 external-resistor value to obtain a percentage output voltage
change of ∆%.
∆%
( V O, nom ( 1 + ---------- ) – 1.225 )
100
R adj-up = ------------------------------------------------------------------------- 205 – 2.255 kΩ
( 1.225∆% )
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
10
RLOAD
TRIM
VI(–)
SENSE(–)
VO(–)
8-748 (C).b
Figure 13. Circuit Configuration to Decrease
Output Voltage
1M
100k
10k
1k
0
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 overvoltage protection as indicated in 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.
SENSE(+)
Radj-down
ADJUSTMENT RESISTOR VALUE (Ω)
The test results for this configuration are displayed in
Figure 14. This figure applies to all output voltages.
VO(+)
ON/OFF
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 equation determines the required external-resistor value to
obtain a percentage output voltage change of ∆%.
205
R adj-down = ---------- – 2.255 k Ω
∆%
Data Sheet
March 2000
10
20
30
40
PERCENT CHANGE IN OUTPUT VOLTAGE (∆%)
8-1171 (C).g
Figure 14. Resistor Selection for Decreased Output
Voltage
VI(+)
ON/OFF
VO(+)
SENSE(+)
Radj-up
CASE
VI(–)
TRIM
RLOAD
SENSE(–)
VO(–)
8-715 (C).b
Figure 15. Circuit Configuration to Increase
Output Voltage
Lucent Technologies Inc.
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
Feature Descriptions (continued)
Synchronization
Output Voltage Set-Point Adjustment (Trim)
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.
ADJUSTMENT RESISTOR VALUE (Ω)
(continued)
10M
SYNC IN Pin
This pin can be connected either to an external clock or
directly to the SYNC OUT pin of another FW250x or
FW300x module.
1M
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 performance of the module and must be avoided.
100k
10k
0
2
4
6
8
10
PERCENT CHANGE IN OUTPUT VOLTAGE (∆%)
8-1172 (C).e
Figure 16. Resistor Selection for Increased Output
Voltage
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.
Output Overvoltage Protection
SYNC OUT Pin
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 proportional to the dc output current of the module given in
the Feature Specifications table. For example, on the
FW250B1, the V/A ratio is set at 180 mV/A ± 10% @
70 °C case. At a full load current of 20.8 A, the voltage
on the CURRENT MON pin is 3.74 V. The current monitor 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 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.
Lucent Technologies Inc.
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 established 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.
11
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
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 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.
Good layout techniques should be observed for noise
immunity. To implement forced load sharing, the following 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 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.
PARALLEL
SENSE(+)
SENSE(–)
CASE
VO(+)
ON/OFF
VI(+)
VO(–)
VI(–)
PARALLEL
SENSE(+)
SENSE(–)
CASE
VO(+)
ON/OFF
VI(+)
VO(–)
VI(–)
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
(1 MΩ) between PWR GOOD and SENSE(–) indicates 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 voltage 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.
When not using the parallel feature, leave the
PARALLEL pin open.
12
Lucent Technologies Inc.
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
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 thermally coupled to the case. Heat is removed by conduction, convection, and radiation to the surrounding
environment. Proper cooling can be verified by measuring the case temperature. Peak temperature occurs
at the position indicated in Figure 18.
POWER DISSIPATION, PD (W)
70
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.)
60
50
40
30
20
10
0.1 m/s (20 ft./min.)
NAT. CONV.
0
0
10
20
30
40
50
60
70
80
90 100
LOCAL AMBIENT TEMPERATURE, TA (°C)
VI(+)
MEASURE CASE
TEMPERATURE HERE
8-1315 (C)
VO(+)
VI(–)
ON/OFF
SYNC IN
30.5
(1.20)
VO(–)
SYNC OUT
Figure 19. Convection Power Derating with No Heat
Sink; Airflow Along Width; Transverse
Orientation
CASE
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
for the module as listed in the Ordering Information table.
POWER DISSIPATION, PD (W)
70
82.6
(3.25)
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.)
60
50
40
30
20
10
0.1 m/s (20 ft./min.)
NAT. CONV.
0
0
10
20
30
40
50
60
70
80
90 100
LOCAL AMBIENT TEMPERATURE, TA (°C)
8-1314 (C)
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).
Figure 20. Convection Power Derating with No Heat
Sink; Airflow Along Length;
Longitudinal Orientation
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 for a given
set of operating conditions. For example, 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.).
Lucent Technologies Inc.
13
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Thermal Considerations (continued)
The power modules have through-threaded, M3 x 0.5
mounting holes, which enable 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 by using
the overall thermal resistance of the module. Total module thermal resistance (θca) is defined as the maximum
case temperature rise (∆TC, max) divided by the module
power dissipation (PD):
(TC – TA)
C, max
θ ca = ∆T
= ------------------------------------------PD
PD
The location to measure case temperature (TC) is
shown in Figure 18. Case-to-ambient thermal resistance 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.
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
45
1.5
1.0
0.5
1.0
(200)
1.5
(300)
2.0
(400)
2.5
(500)
1.5
(300)
2.0
(400)
2.5
(500)
3.0
(600)
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 generally 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.
50
0.5
(100)
1.0
(200)
Figure 22. Case-to-Ambient Thermal Resistance
Curves; Longitudinal Orientation
2.0
0
0.5
(100)
8-1320 (C)
2.5
0.0
0
AIR VELOCITY, m/s (ft./min.)
3.0
(600)
AIR VELOCITY, m/s (ft./min.)
8-1321 (C)
Figure 21. Case-to-Ambient Thermal Resistance
Curves; Transverse Orientation
POWER DISSIPATION, P D (W)
CASE-TO-AMBIENT THERMAL
RESISTANCE, θCA (°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
3.0
1 1/2 IN. HEAT SINK
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
4.0
To choose a heat sink, determine the power dissipated
as heat by the unit for the particular application.
Figures 23 and 24 show typical heat dissipation for a
range of output currents and three voltages for the
FW250B1 and FW300B1.
4.5
3.5
CASE-TO-AMBIENT THERMAL
RESISTANCE, θCA (°C/W)
4.5
Heat Transfer with Heat Sinks
4.0
Data Sheet
March 2000
40
VI = 75 V
VI = 55.5 V
VI = 36 V
35
30
25
20
15
10
5
0
0
2
4
6
8
10
12
14
16
18
20
OUTPUT CURRENT, IO (A)
8-1732 (C)
Figure 23. FW250B1 Power Dissipation vs. Output
Current at 25 °C
14
Lucent Technologies Inc.
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
Thermal Considerations (continued)
Use Figures 21 and 22 to determine air velocity for the
1 inch heat sink. The minimum airflow necessary for
the FW300B1 module depends on heat sink fin orientation and is shown below:
Heat Transfer with Heat Sinks (continued)
50
POWER DISSIPATION, P D (W)
45
■
1.4 m/s (270 ft./min.) (oriented along width)
■
1.7 m/s (330 ft./min.) (oriented along length)
40
35
Custom Heat Sinks
VI = 75 V
VI = 54 V
VI = 36 V
30
25
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 25.
20
15
10
5
0
0
2
4
6
8
10
12
14 16
18
20 22
24
PD
OUTPUT CURRENT, IO (A)
TC
8-1733 (C)
Figure 24. FW300B1 Power Dissipation vs. Output
Current at 25 °C
TS
cs
TA
sa
8-1304(C)
Figure 25. Resistance from Case-to-Sink and Sinkto-Ambient
Example
If an 85 °C case temperature is desired, what is the
minimum airflow necessary? Assume the FW300B1
module is operating at VI = 54 V and an output current
of 25 A, maximum ambient air temperature of 40 °C,
and the heat sink is 1 inch.
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:
Solution
This equation assumes that all dissipated power must
be shed by the heat sink. Depending on the userdefined application environment, a more accurate
model, including heat transfer from the sides and bottom of the module, can be used. This equation provides
a conservative estimate for such instances.
Given: VI = 54 V
IO = 25 A
TA = 40 °C
TC = 85 °C
Heat sink = 1 inch
(TC – TA)
θ sa = ------------------------- – θ cs
PD
Determine PD by using Figure 23:
PD = 45 W
Then solve the following equation:
EMC Considerations
TC – TA)
θ ca = (----------------------PD -
For assistance with designing for EMC compliance,
please refer to the FLTR100V10 data sheet
(DS99-294EPS).
85 – 40 )
θ ca = (-----------------------
Layout Considerations
45
θ ca = 1.0 °C/W
Lucent Technologies Inc.
Copper paths must not be routed beneath the power
module mounting inserts. For additional layout guidelines, refer to the FLTR100V10 data sheet
(DS99-294EPS).
15
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
Outline Diagram
Dimensions are in millimeters and (inches).
Tolerances: x.x mm ± 0.5 mm (x.xx in. ± 0.02 in.),
x.xx mm ± 0.25 mm (x.xxx in. ± 0.010 in.)
Top View
116.8 (4.60)
61.0
(2.40)
Side View
SIDE LABEL*
13.5
(0.53)
1.57 ± 0.05 (0.062 ± 0.002) DIA
SOLDER-PLATED BRASS,
11 PLACES,
(VOUT–, VOUT+, VIN–, VIN+)
5.1 (0.20) MIN
1.02 ± 0.05 (0.040 ± 0.002) DIA
SOLDER-PLATED BRASS,
9 PLACES
Bottom View
MOUNTING INSERTS
M3 x 0.5 THROUGH,
4 PLACES
66.04 (2.600)
2.54 (0.100) TYP
12.7
(0.50)
7.62
(0.300)
30.48
(1.200)
50.8
(2.00)
CASE
SYNC OUT
SYNC IN
ON/OFF
2.54 (0.100) TYP
SENSE–
SENSE+
TRIM
PARALLEL
CURRENT MON
PWR GOOD
12.70
17.78 (0.500)
(0.700)
22.86
(0.900)
5.1 (0.20)
VO–
VI–
VO+
10.16
(0.400) 15.24
(0.600)
30.48
5.08
(1.200)
20.32
(0.200)
(0.800)
25.40
(1.000)
35.56
(1.400)
VI+
5.1 (0.20)
106.68 (4.200)
8-1650 (C)
* Side label includes Tyco name, product designation, safety agency markings, input/output voltage and current ratings and bar code.
16
Lucent Technologies Inc.
Data Sheet
March 2000
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Recommended Hole Pattern
Component-side footprint.
Dimensions are in millimeters and (inches).
MOUNTING INSERTS
66.04 (2.600)
2.54 (0.100) TYP
7.62
(0.300)
5.1 (0.20)
7.62
12.7
(0.300) (0.50)
30.48
(1.200)
20.32
(0.800)
10.16
(0.400)
5.08
(0.200)
VO–
25.40
35.56 (1.000)
(1.400)
PWR GOOD
CURRENT MON
PARALLEL
TRIM
SENSE+
SENSE–
15.24
(0.600)
2.54 (0.100) TYP
7.62
(0.300)
CASE
SYNC OUT
SYNC IN
ON/OFF
VI–
VO+
VI+
12.70
(0.500) 17.78
(0.700)
22.86
(0.900)
30.48
(1.200)
50.8
(2.00)
5.1 (0.20)
106.68 (4.200)
8-1650 (C)
Ordering Information
Table 5. Device Codes
Input Voltage
48 V
48 V
Lucent Technologies Inc.
Output Voltage
12 V
12 V
Output Power
250 W
300 W
Device Code
FW250B1
FW300B1
Comcode
107961492
107504490
17
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
Ordering Information (continued)
Table 6. Device Accessories
Accessory
Comcode
1/4 in. transverse kit (heat sink, thermal pad, and screws)
1/4 in. longitudinal kit (heat sink, thermal pad, and screws)
1/2 in. transverse kit (heat sink, thermal pad, and screws)
1/2 in. longitudinal kit (heat sink, thermal pad, and screws)
1 in. transverse kit (heat sink, thermal pad, and screws)
1 in. longitudinal kit (heat sink, thermal pad, and screws)
1 1/2 in. transverse kit (heat sink, thermal pad, and screws)
1 1/2 in. longitudinal kit (heat sink, thermal pad, and screws)
847308335
847308327
847308350
847308343
847308376
847308368
847308392
847308384
Dimension are in millimeters and (inches).
1/4 IN.
1/4 IN.
59.94
(2.36)
1/2 IN.
115.82
(4.56)
1 IN.
1/2 IN.
1 IN.
115.82
(4.56)
1 1/2 IN.
1 1/2 IN.
8-2831 (C)
60.45
(2.38)
8-2830 (C)
Figure 27. Transverse Heat Sink
Figure 26. Longitudinal Heat Sink
18
Lucent Technologies Inc.
Data Sheet
March 2000
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Notes
Lucent Technologies Inc.
19
FW250B1 and FW300B1 Power Modules: dc-dc Converters:
36 Vdc to 75 Vdc Input, 12 Vdc Output; 250 W to 300 W
Data Sheet
March 2000
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.
March 2000
DS99-325EPS (Replaces DS97-518EPS)
Printed on
Recycled Paper
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