SQ24X03150 Power-One, SQ24X03150 Datasheet - Page 4

• Manufacturer Part Number: SQ24X03150
• Description: Sq24t/s03150 Dc-dc Converter 19-36 Vdc Input; 15 Vdc Output @ 3.3 A
• Manufacturer: Power-One

Operation
Input and Output Impedance
These power converters have been designed to be
stable with no external capacitors when used in low
inductance input and output circuits.
However, in many applications, the inductance
associated with the distribution from the power
source to the input of the converter can affect the
stability of the converter. The addition of a 100 µF
electrolytic capacitor with an ESR < 1 Ω across the
input helps ensure stability of the converter. In many
applications, the user has to use decoupling
capacitance at the load. The power converter will
exhibit
capacitance up to 1000 µF.
ON/OFF (Pin 2)
The ON/OFF pin is used to turn the power converter
on or off remotely via a system signal. There are two
remote control options available, positive logic and
negative logic and both are referenced to Vin(-).
Typical connections are shown in Fig. A.
The positive logic version turns on when the ON/OFF
pin is at logic high and turns off when at logic low.
The converter is on when the ON/OFF pin is left
open
The negative logic version turns on when the pin is
at logic low and turns off when the pin is at logic
high. The ON/OFF pin can be hard wired directly to
Vin(-) to enable automatic power up of the converter
without the need of an external control signal.
The ON/OFF pin is internally pulled-up to 5 V
through a resistor. A mechanical switch, open
collector transistor, or FET can be used to drive the
input of the ON/OFF pin. The device must be
capable of sinking up to 0.2 mA at a low level voltage
of ≤ 0.8 V. An external voltage source of ±20 V max.
may be connected directly to the ON/OFF input, in
which case it should be capable of sourcing or
JAN 21, 2004 revised to AUG 23, 2006
Vin
Fig. A: Circuit configuration for ON/OFF function.
.
CONTROL
INPUT
stable
Vin (+)
ON/OFF
Vin (-)
operation
Semi
Converter
(Top View)
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TM
Family
with
SENSE (+)
SENSE (-)
Vout (+)
Vout (-)
external
TRIM
SQ24T/S03150 DC-DC Converter Data Sheet
load
Page 4 of 15
19-36 VDC Input; 15 VDC Output @ 3.3 A
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sinking up to 1 mA depending on the signal polarity.
See the Start-up Information section for system
timing waveforms associated with use of the
ON/OFF pin.
Remote Sense (Pins 5 and 7)
The
compensates for voltage drops occurring between
the output pins of the converter and the load. The
SENSE(-) (Pin 5) and SENSE(+) (Pin 7) pins should
be connected at the load or at the point where
regulation is required (see Fig. B).
If remote sensing is not required, the SENSE(-) pin
must be connected to the Vout(-) pin (Pin 4), and the
SENSE(+) pin must be connected to the Vout(+) pin
(Pin 8) to ensure the converter will regulate at the
specified output voltage. If these connections are not
made, the converter will deliver an output voltage
that is slightly higher than the specified value.
Because the sense leads carry minimal current,
large traces on the end-user board are not required.
However, sense traces should be located close to a
ground plane to minimize system noise and insure
optimum performance. When wiring discretely,
twisted pair wires should be used to connect the
sense lines to the load to reduce susceptibility to
noise.
The converter’s output over-voltage protection (OVP)
senses the voltage across Vout(+) and Vout(-), and
not across the sense lines, so the resistance (and
resulting voltage drop) between the output pins of
the converter and the load should be minimized to
prevent unwanted triggering of the OVP.
When utilizing the remote sense feature, care must
be taken not to exceed the maximum allowable
output power capability of the converter, equal to the
product of the nominal output voltage and the
allowable output current for the given conditions.
Vin
remote
Fig. B: Remote sense circuit configuration.
Vin (+)
ON/OFF
sense
Vin (-)
Semi
feature
Converter
(Top View)
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TM
Family
www.power-one.com
of
SENSE (+)
SENSE (-)
Vout (+)
Vout (-)
TRIM
the
100
10
converter
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Rw
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