JFW100G Lineage Power, JFW100G Datasheet - Page 14

• Manufacturer Part Number: JFW100G
• Manufacturer: Lineage Power

dc-dc Converters; 36 to 75 Vdc Input; 2.5 Vdc Output; 25 W to 75 W
Feature Descriptions
Overtemperature Protection
These modules feature an overtemperature protection
circuit to safeguard against thermal damage. The cir-
cuit shuts down and latches off the module when the
maximum case temperature is exceeded. The module
can be restarted by cycling the dc input power for at
least 1.0 second or by toggling the primary or second-
ary referenced remote on/off signal for at least
1.0 second.
Power Good Signal
The power good signal (PWRGOOD pin) is an open-
collector, secondary-referenced pin that is pulled low
when all five of the following conditions are met:
1. The sensed output voltage is greater than half the
2. The overvoltage shutdown latch is not set.
3. The thermal shutdown latch is not set.
4. The unit is not in current limit.
5. Secondary internal bias is present.
There is one situation where the power good signal can
be low even though the module has failed. This can
occur when the module is paralleled with other mod-
ules for additional output power (i.e., the output ORing
diodes would not be used). If one module power train
stops delivering power (fails), the other paralleled mod-
ule(s) would provide a voltage at the output pin of the
failed module. The failed module would then not detect
that its output power is not being delivered. However, in
this situation, the current monitor pins of the paralleled
modules would indicate that current is not being deliv-
ered from one module and that module had failed.
For redundant applications, the ORing diodes would
keep the other module voltages from being applied to
the failed module output and the power good signal
would indicate a failure.
Thermal Warning Signal
The thermal warning (TEMPWARN) pin is a second-
ary-referenced, open-collector output that shorts to
SENSE(–) a few degrees before the module goes into
thermal shutdown. When the module temperature
cools, the thermal warning pin will open, but the unit
will remain latched off until the input power or the pri-
mary or secondary referenced remote on/off is recycled
for 1.0 second.
14
14
rated nominal output voltage.
(continued)
Thermal Considerations
Introduction
The JFW-Series power modules operate in a variety of
thermal environments; however, sufficient cooling
should be provided to help ensure reliable operation of
the units. Heat-dissipating components inside the units
are thermally coupled to the case. Heat is removed by
conduction, convection, and radiation to the surround-
ing environment. Proper cooling can be verified by
measuring the case temperature. Peak temperature
(T
Note: Top view, measurements shown in millimeters and (inches).
Figure 21. Case Temperature Measurement
The temperature at this location should not exceed
100 °C. The output power of the module should not
exceed the rated power for the module as listed in the
Ordering Information table.
Although the maximum case temperature of the power
modules is 100 °C, you can limit this temperature to a
lower value for extremely high reliability.
For additional information regarding this module, refer to
the Thermal Management JC-, JFC-, JW-, and JFW-
Series 50 W to 150 W Board-Mounted Power Modules
Technical Note (TN97-008EPS).
7.6 (0.30)
C
) occurs at the position indicated in Figure 21.
Pin locations are for reference only.
Location
38.0 (1.50)
TEMPERATURE HERE
MEASURE CASE
Lineage Power
April 2008
8-1397 (C).a