QBDW033A0B41Z Datasheet, PDF (10/17 Pages) Lineage Power Corporation – QBDW033A0B Series Power Modules; DC-DC Converters

Advanced Data Sheet
February 10, 2011
QBDW033A0B Series Power Modules; DC-DC Converters
36-75V_dc Input; 9.6-12V_dc Output; 33A Output Current
Feature Descriptions (continued)
The voltage between the Vo(+) and Vo(–) terminals must
not exceed the minimum output overvoltage protection
value shown in the Feature Specifications table. This limit
includes any increase in voltage due to remote-sense
compensation and output voltage set-point adjustment trim.
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.
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 (Maximum rated power = VO,set x
IO,max).
Active Load Sharing, CS
For additional power requirements, the QBDW033A0B
power module can be configured for parallel operation with
active load sharing. Good layout techniques should be
observed for noise immunity when using multiple units in
parallel. To implement active load sharing, the following
requirements should be followed:
 The Vout(+) and Vout(-) planes of all parallel modules
must be connected together with output traces from
each module as short as possible to common power
planes.
 The SENSE(+) and SENSE(-) connections to each
module should come from a single point in each power
plane.
 The current share (CS) pins of all units in parallel must
be connected together. The path of these connections
should be as direct as possible. SIGGND is the return
for the CS signal for each module; therefore, all
modules in parallel must use the same SIGGND.
 These modules contain circuitry to block reverse
current flow upon start-up, when output voltage is
present from other parallel modules, eliminating the
requirement for external output ORing devices.
However, output ORing devices should be used, if fault
tolerance is desired in parallel applications.
 When not using the parallel feature, leave the CS
open.
Power Good, PG
The QBDW033A0B modules provide a Power Good (PG)
signal that is implemented with an open-drain output to
indicate that the output voltage is within the regulation limits
of the power module. The PG signal will be de-asserted to a
low state if any condition such as overtemperature,
overcurrent or loss of regulation occurs that would result in
the output voltage going ±TBD% outside the setpoint value.
The PG terminal should be connected through a pullup
resistor (suggested value TBDK) to a source of TBDVdc or
less.
Thermal Considerations
The power modules operate in a variety of thermal
environments and sufficient cooling should be provided to
help ensure reliable operation.
Thermal considerations include ambient temperature,
airflow, module power dissipation, and the need for
increased reliability. A reduction in the operating
temperature of the module will result in an increase in
reliability. The thermal data presented here is based on
physical measurements taken in a wind tunnel.
Heat-dissipating components are mounted on the top side
of the module. Heat is removed by conduction, convection
and radiation to the surrounding environment. Proper
cooling can be verified by measuring the thermal reference
temperature (THx). Peak temperature (THx) occurs at the
position indicated in Figure 14 and 15. For reliable
operation this temperature should not exceed the listed
temperature threshold.
.
Figure 14. Location of the thermal reference
temperature TH.
LINEAGE POWER
Figure 15. Location of the thermal reference
temperature TH3 for Baseplate module.
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