PQ60025QPA60 Datasheet, PDF (10/14 Pages) SynQor Worldwide Headquarters – Quarter-brick DC/DC Converter

Technical Specification
Input: 35-75 V
Output: 2.5 V
Current: 60 A
Package: Quarter-brick
BASIC OPERATION AND FEATURES
The PowerQor series converter uses a two-stage power conver-
sion topology. The first stage is a buck-converter that keeps the
output voltage constant over variations in line, load, and temper-
ature. The second stage uses a transformer to provide the func-
tions of input/output isolation and voltage step-down to achieve
the low output voltage required.
Both the first stage and the second stage switch at a fixed fre-
quency for predictable EMI performance. Rectification of the
transformer’s output is accomplished with synchronous rectifiers.
These devices, which are MOSFETs with a very low on-state resis-
tance, dissipate far less energy than Schottky diodes. This is the
primary reason that the PowerQor converter has such high effi-
ciency, even at very low output voltages and very high output cur-
rents.
Dissipation throughout the converter is so low that it does not
require a heatsink for operation. Since a heatsink is not required,
the PowerQor converter does not need a metal baseplate or pot-
ting material to help conduct the dissipated energy to the
heatsink. The PowerQor converter can thus be built more simply
and reliably using high yield surface mount techniques on a PCB
substrate.
The PowerQor series of half-brick, quarter-brick and eighth-brick
converters uses the industry standard footprint and pin-out con-
figuration.
CONTROL FEATURES
REMOTE ON/OFF (Pin 2): The ON/OFF input, Pin 2, permits
the user to control when the converter is on or off. This input is
referenced to the return terminal of the input bus, Vin(-). There
are two versions of the converter that differ by the sense of the
logic used for the ON/OFF input.
In the positive logic version, the ON/OFF input is active high
(meaning that a high turns the converter on). In the negative logic
version, the ON/OFF signal is active low (meaning that a low
turns the converter on). Figure A details five possible circuits for
driving the ON/OFF pin. Figure B is a detailed look of the inter-
nal ON/OFF circuitry.
REMOTE SENSE(+) (Pins 8 and 6): The SENSE(+) inputs cor-
rect for voltage drops along the conductors that connect the con-
verter’s output pins to the load.
Pin 8 should be connected to Vout(+) and Pin 6 should be con-
nected to Vout(-) at the point on the board where regulation is
desired. A remote connection at the load can adjust for a voltage
drop only as large as that specified in this datasheet, that is
[Vout(+) - Vout(-)] – [Vsense(+) - Vsense(-)] <
Sense Range % x Vout
Pins 8 and 6 must be connected for proper regulation of the out-
put voltage. If these connections are not made, the converter will
deliver an output voltage that is slightly lower than its specified
value.
Note: the output over-voltage protection circuit senses the voltage
ON/OFF
ON/OFF
ON/OFF
Vin(_)
Remote Enable Circuit
Vin(_)
Negative Logic
(Permanently Enabled)
Vin(_)
Positive Logic
(Permanently Enabled)
ON/OFF
5V
TTL/
CMOS
ON/OFF
Vin(_)
Vin(_)
Open Collector Enable Circuit
Direct Logic Drive
Figure A: Various circuits for driving the ON/OFF pin.
Product # PQ60025QPA60
Phone [phone]
www.synqor.com
Vin(+)
ON/OFF
Vin(^_)
274k
50k
100pF
50k
5V
TTL
Figure B: Internal ON/OFF pin circuitry
Doc.# 005-2QP625F Rev. A 12/10/04
Page 10