7 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

7.1 Application Information

The TPS792xx family of LDO regulators has been optimized for use in noise-sensitive battery-operated

equipment. The device features extremely low dropout voltages, high PSRR, low output noise, low quiescent

current, and enable-input to reduce supply currents to less than 1μA when the regulator is turned off.

7.1.1 Adjustable Operation

The output voltage of the TPS792xx01 adjustable regulator is programmed using an external resistor divider as

shown in the image below. The output voltage is calculated using the equation below:

1

OUT

REF

2

R

V

V

1

R

æ

ö

=

´

+

ç

÷

è

ø

(1)

where:

• VREF = 1.2246V typ (the internal reference voltage)

Resistors R1 and R2 must be selected for approximately 50μA divider current. Lower value resistors can be

used for improved noise performance, but the solution consumes more power. Higher resistors values can cause

accuracy issues and other problems. The recommended design procedure is to choose R2 = 30.1kΩ to set the

divider current at 50μA, CFF = 15pF for stability, and then calculate R1 using the equation below:

OUT

1

2

REF

V

R

1

R

V

æ

ö

=

-

´

ç

÷

è

ø

(2)

To improve the stability of the adjustable version, place a small compensation capacitor between OUT and FB.

For output voltages less than 1.8V, the value of this capacitor must be 100pF. For output voltages greater than

1.8V, the approximate value of this capacitor can be calculated as shown in the equation below:

C

=

FF

(3

10 )

(R + R )

(R

R )

-7

1

2

1

2

´

´

´

(3)

The suggested value of this capacitor for several resistor ratios is shown in the table in the image below. If this

capacitor is not used (such as in a unity-gain configuration) or if an output voltage less than 1.8V is chosen, then

the minimum recommended output capacitor is 4.7μF instead of 2.2μF.

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TPS792

SLVS337E – MARCH 2001 – REVISED JANUARY 2025

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