MCOTS-C-48-30-QT SynQor Worldwide Headquarters, MCOTS-C-48-30-QT Datasheet - Page 8

• Manufacturer Part Number: MCOTS-C-48-30-QT
• Description: High Reliability Dc-dc Converter
• Manufacturer: SynQor Worldwide Headquarters

Product # MCOTS-C-48-30-QT
BASIC OPERATION AND FEATURES
This Mil-COTS converter series uses a two-stage power
conversion topology. The first stage is a buck-converter that
keeps the output voltage constant over variations in line, load,
and temperature. The second stage uses a transformer to
provide the functions of input/output isolation and voltage
step-up or step-down to achieve the output voltage required.
Both the first stage and the second stage switch 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 converter are offered totally encased to withstand
harsh environments and thermally demanding applications.
Dissipation
it does not require a heatsink for operation in many
applications; however, adding a heatsink provides improved
thermal
This series of converters use the industry standard footprint
and pin-out configuration.
Figure A: Various circuits for driving the ON/OFF pin.
Technical Specification
Remote Enable Circuit
Open Collector Enable Circuit
derating
throughout
Vin(
ON/OFF
performance
_
)
ON/OFF
Vin(
the
Phone [phone]
_
)
Negative Logic
(Permanently
converter
Enabled)
CMOS
TTL/
Direct Logic Drive
in
ON/OFF
Vin(
5V
_
)
extreme
is
so
ON/OFF
Vin(
situations.
_
low
)
www.synqor.com
that
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
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.
[
Vout(+) - Vout(-)
ON/OFF
Doc.# 005-0005423 Rev. B
V
in(
Figure B: Internal ON/OFF pin circuitry
_
)
Sense Range % x Vout
]
–
OPEN
[V
50k
MCOTS-C-48-30-QT
50k
Current:
Output:
sense(+) -
100pF
V
04/23/10
30V
5.0A
sense(-)
5V
TTL
]
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