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APPLICATION INFORMATION

C1

0.1

µF

PG

OUT

4

3

IN

NC

GND

2

1

5

0.47

µF

+

TPS797xx

100 k

Ω

+

−

External Capacitor Requirements

Power Dissipation and Junction Temperature

The maximum-power-dissipation limit is determined using the following equation:

P

D(max) +

T

J

max * TA

RθJA

TPS79718-EP, TPS79730-EP, TPS79733-EP

SGLS348A – AUGUST 2006 – REVISED OCTOBER 2007

The TPS797xx family of low-dropout (LDO) regulators haS been optimized for use in micropower applications.

The devices feature extremely low dropout voltages and ultralow quiescent current (1.2

µA typ).

A typical application circuit is shown in Figure 14.

Figure 14. Typical Application Circuit

Although not required, a 0.1

µF or larger input bypass capacitor, connected between IN and GND and located

close to the TPS797xx, is recommended, especially when a highly resistive power supply is powering the LDO in

addition to other devices.

Like all low-dropout regulators, the TPS797xx requires an output capacitor connected between OUT and GND to

stabilize the internal control loop. The minimum recommended capacitance is 0.47

µF. Any 0.47 µF capacitor is

suitable. Capacitor values larger than 0.47

µF are acceptable.

Specified regulator operation is assured to a junction temperature of 125

°C; restrict the maximum junction

temperature to 125

°C under normal operating conditions. This restriction limits the power dissipation the

regulator can handle in any given application. To ensure the junction temperature is within acceptable limits,

Where:

TA is the ambient temperature.

The regulator dissipation is calculated using:

Power dissipation resulting from quiescent current is negligible. Excessive power dissipation triggers the thermal

protection circuit.

8

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