DEVICE INFORMATION

PTHXX020

(Top View)

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PTH12020W/L

TERMINAL FUNCTIONS

TERMINAL

DESCRIPTION

NAME

NO.

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The positive input voltage power node to the module, which is referenced to common GND.

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The regulated positive power output with respect to the GND node.

This is the common ground connection for the Vin and Vout power connections. It is also the 0 VDC reference for the

GND

1, 7

control inputs.

The Inhibit pin is an open-collector/drain negative logic input that is referenced to GND. Applying a lowlevel ground

signal to this input disables the module’s output and turns off the output voltage. When the Inhibit control is active, the

input current drawn by the regulator is significantly reduced. If the inhibit feature is not used, the control pin should be

Inhibit

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left open-circuit. The module will then produce an output whenever a valid input source is applied. Do not place an

external pull-up on this pin. For power-up into a non-prebiased output, it is recommended that AutoTrack be utilized for

On/Off control. See the Application Information for additional details.

A 1% resistor must be connected directly between this pin and GND (pin 7) to set the output voltage of the module

higher than its lowest value. The temperature stability of the resistor should be 100 ppm/°C (or better). The set point

range is 1.2 V to 5.5 V for W-suffix devices, and 0.8 V to 1.8 V for L-suffix devices. The resistor value required for a

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given output voltage may be calculated using a formula. If left open circuit, the module output voltage will default to its

Adjust

lowest value. For further information on output voltage adjustment consult the related application note.

The specification table gives the preferred resistor values for a number of standard output voltages.

The sense input allows the regulation circuit to compensate for voltage drop between the module and the load. For

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Sense

This is an analog control input that enables the output voltage to follow an external voltage. This pin becomes active

typically 20 ms after the input voltage has been applied, and allows direct control of the output voltage from 0 V up to

the nominal set-point voltage. Within this range the output will follow the voltage at the Track pin on a volt-for-volt basis.

When the control voltage is raised above this range, the module regulates at its set-point voltage. The feature allows

Track

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the output voltage to rise simultaneously with other modules powered from the same input bus. If unused this input

should be connected to Vin.

NOTE: Due to the under-voltage lockout feature, the output of the module cannot follow its own input voltage during

power up. For more information, consult the related application note.

When this input is asserted to GND, the output voltage is decreased by 5% from the nominal. The input requires an

Margin

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open-collector (open-drain) interface. It is not TTL compatible. A lower percent change can be accomodated with a

Down

series resistor. For further information, consult the related application note.

When this input is asserted to GND, the output voltage is increased by 5%. The input requires an open-collector

Margin

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(open-drain) interface. It is not TTL compatible. The percent change can be reduced with a series resistor. For further

Up

information, consult the related application note.

Copyright © 2003–2009, Texas Instruments Incorporated

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Product Folder Link(s) :PTH12020W/L