JBW030-Series Power Module: dc-dc Converters
36-75 Vdc Input; 3.3 Vdc and 5 Vdc Outputs; 30 W
Data Sheet
March 27, 2008
Design Considerations
Grounding Considerations
The case is not connected internally to allow the user
flexibility in grounding.
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.
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. A 33 µF electrolytic capacitor (ESR < 0.7
Ω
at
100 kHz) mounted close to the power module helps
ensure stability of the unit. (See Figure 11.)
Remote On/Off
Two remote on/off options are available. Positive logic
remote on/off turns the module on during a logic-high
voltage on the REMOTE ON/OFF pin, and off during a
logic low. Negative logic remote on/off turns the module
off during a logic high and on during a logic low. Nega-
tive logic, device code suffix “1,” is the factory-preferred
configuration.
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 V
I
(–) terminal (V
on/off
). The
switch can be an open collector or equivalent (see Fig-
ure 14). A logic low is V
on/off
= –0.7 V to 1.2 V, during
which the module is off. The maximum I
on/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 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.
The module has internal capacitance to reduce noise
at the ON/OFF pin. Additional capacitance is not gen-
erally needed and may degrade the start-up character-
istics of the module.
CAUTION: To avoid damaging the power module
or external on/off circuit, the connec-
tion between the V
I
(–) pin and the input
source must be made before or simulta-
neously to making a connection
between the ON/OFF pin and the input
source (either directly or through the
external on/off circuit.)
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
60950,
CSA
C22.2 No. 60950-00, and EN
60950 (VDE0805):2001-12.
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:
n
The input source is to be provided with reinforced
insulation from any other hazardous voltages, includ-
ing the ac mains.
One V
I
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 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.
n
n
n
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 pins 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 5 A fast-acting fuse in the ungrounded lead.
8
Lineage Power
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
