TPS72201, TPS72215

TPS72216, TPS72218

SLVS390B – DECEMBER 2001 – REVISED MAY 2002

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APPLICATION INFORMATION

The TPS722xx family of low-dropout (LDO) regulators functions with a very low input voltage (>1.8 V). The dropout voltage

is typically 50 mV at full load. Typical quiescent current (ground pin current) is only 85

µA and drops to 1 µA in the shutdown

mode.

DEVICE OPERATION

The TPS722xx family can be operated at low input voltages due to low voltage circuit design techniques and a PMOS pass

element that exhibits low dropout.

A logic low on the enable input, EN, shuts off the output and reduces the supply current to less than 1

µA. EN may be tied

Current limiting and thermal protection prevent damage by excessive output current and/or power dissipation. The device

switches into a constant-current mode at approximately 350 mA; further load reduces the output voltage instead of

increasing the output current. The thermal protection shuts the regulator off if the junction temperature rises above 170

°C.

Recovery is automatic when the junction temperature drops approximately 20

°C below the high temperature trip point. The

PMOS pass element includes a back diode that safely conducts reverse current when the input voltage level drops below

the output voltage level.

A typical application circuit is shown in Figure 16.

NC

OUT

1

3

IN

EN

GND

2

4

5

VI

VO

0.1

µF

+

TPS722xx

0.1

µF

Figure 16. Typical Application Circuit

DUAL SUPPLY APPLICATION

the DSP or microcontroller. As shown in Figure 17, two AAA batteries provide an input voltage to a boost converter and

the TPS72115 LDO linear regulator. The batteries combine input voltage ranges from 3.0 V down to 1.8 V near the end

much faster (<400

µs) than the output of any switching type boost converter due to the inherent slow start up of those types

can be used over the entire life of the two off-the-shelf AAA batteries. Thus, this solution is very efficient and the design

time and overall cost of the solution is minimized.