PQ60120SMX04 Datasheet, PDF (11/15 Pages) SynQor Worldwide Headquarters – Fixed frequency switching provides predictable EMI

Technical
Specification
PQ60120SMx04
BASIC OPERATION AND FEATURES
This converter switches at a fixed frequency 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 resistance, dissipate far
less energy than Schottky diodes. This is the primary reason
that the converter has such high efficiency, even at very low
output voltages and very high output currents.
These converters are offered totally encased to withstand harsh
environments and thermally demanding applications. Dissipation
throughout the converter is so low that it does not require a
heatsink for operation in many applications; however, adding
a heatsink provides improved thermal derating performance in
extreme situations.
This series of converters uses the industry standard footprint
and pin-out configuration.
ON/OFF
ON/OFF
Vin(^_)
Remote Enable Circuit
Vin(^_)
Negative Logic
(Permanently Enabled)
ON/OFF
5V
TTL/
CMOS
ON/OFF
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(-).
The ON/OFF signal is active low (meaning that a low turns the
converter on). Figure A details four possible circuits for driving
the ON/OFF pin. Figure B is a detailed look of the internal ON/
OFF circuitry.
REMOTE SENSE(+) (Pins 7 and 5): The SENSE(+) inputs
correct for voltage drops along the conductors that connect the
converter’s output pins to the load.
Pin 7 should be connected to Vout(+) and Pin 5 should be
connected 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 7 and 5 must be connected for proper regulation of
the output voltage. If these connections are not made, the
converter will deliver an output voltage that is slightly higher
than its specified value.
Note: the output over-voltage protection circuit senses the
voltage across the output (pins 8 and 4) to determine when
it should trigger, not the voltage across the converter’s sense
leads (pins 7 and 5). Therefore, the resistive drop on the board
should be small enough so that output OVP does not trigger,
even during load transients.
5V
Vin(^_)
Open Collector Enable Circuit
Vin(^_)
Direct Logic Drive
Figure A: Various circuits for driving the ON/OFF pin.
10k
ON/OFF
50k
TTL
1000pF
Vin(^_)
Figure B: Internal ON/OFF pin circuitry
Product # PQ60120SMx04
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www.synqor.com
Doc.# 005-0005169 Rev. D
11/13/15
Page 11