JBW050F Power Modules: dc-dc Converter;
36 to 75 Vdc Input, 3.3 Vdc Output; 33 W
Data Sheet
September 20, 2004
Test Configurations (continuted)
Design Considerations
Input Source Impedance
COPPER STRIP
VO(+)
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 33 µF elec-
trolytic capacitor (ESR < 0.7 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.
RESISTIVE
LOAD
1.0 µF
10 µF SCOPE
VO(–)
8-513.d
Note: Use a 1.0 µF ceramic capacitor and a 10 µF aluminum or tan-
talum capacitor. Scope measurement should be made using a
BNC socket. Position the load between 51 mm and 76 mm
(2 in. and 3 in.) from the module.
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., UL60950, CSA C22.2 No. 60950-00, and
EN 60950 (VDE0805):2001-12.
Figure 9. Peak-to-Peak Output Noise
Measurement Test Setup
SENSE(+)
CONTACT AND
DISTRIBUTION LOSSES
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:
VI(+)
VI(–)
VO(+)
II
IO
LOAD
SUPPLY
VO(–)
CONTACT
RESISTANCE
■ The input source is to be provided with reinforced
insulation from any hazardous voltages, including the
ac mains.
SENSE(–)
8-749
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.
■ 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 acces-
sible.
[VO(+) – VO(–)]IO
------------------------------------------------
η =
x 100
%
[VI(+) – VI(–)]II
■ 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.
Figure 10. Output Voltage and Efficiency
Measurement Test Setup
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 maxi-
mum 10 A fast-acting fuse in the ungrounded lead.
Tyco Electronics Power Systems
7
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
