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Positive Output Enable (PEN)

PTQA430025, PTQA430033

SLTS261 – MAY 2006

For those models with the positive enable (PEN) option, leaving pin 2 open circuit, (or driving it to an equivalent

logic high voltage), will enable the converter output. This allows the module to produce an output voltage

pin 2 the converter output is disabled. Table 2 gives the input requirements of pin 2 for modules with the PEN

option.

Table 2. On/Off Control Requirements

for Positive Enable

PARAMETER

MIN

TYP

MAX

Enable

4.5 V

20 V

Disable

–0.2 V

0.8 V

Open-Circuit

5 V

7 V

–0.5 mA

Notes:

2. An open-collector device (preferably a discrete transistor) is recommended. A pull-up resistor is not required.

If one is added the pull-up voltage should not exceed 20 V.

20 V. Exceeding this voltage will overstress, and possibly damage, the converter.

3. The Remote On/Off pin may be controlled with devices that have a totem-pole output. This is provided the

a pull-up resistor may be required to the logic supply voltage.

4. The converter incorporates an undervoltage lockout (UVLO). The UVLO keeps the converter off until the

input voltage is close to the minimum specified operating voltage. This is regardless of the state of the

Remote On/Off control. Consult the product specification for the UVLO input voltage thresholds.

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