V

1 )

R1

R2

R1 +

V

OUT

V

REF

* 1

R2

OUTPUTVOLTAGE

PROGRAMMINGGUIDE

OUTPUT

VOLTAGE

R1

R2

1.8V

2.8V

5.0V

392MW

1.07MW

2.55MW

806kW

806kW

806kW

V

IN

FB

GND

IN

0.1 F

m

TPS71401

OUT

0.47 F

m

V

OUT

R1

R2

TPS714xx

SBVS116C

– DECEMBER 2008 – REVISED MARCH 2011

www.ti.com

Programming the TPS71401 Adjustable LDO Regulator

The output voltage of the TPS71401 adjustable regulator is programmed using an external resistor divider as

shown in Figure 16. The output voltage is calculated using Equation 3:

(3)

where:

Resistors R1 and R2 should be chosen for approximately a 1.5

μA divider current. Lower value resistors can be

used for improved noise performance, but the solution consumes more power. Higher resistor values should be

avoided because leakage current out of the FB pin across R1/R2 creates an offset voltage that artificially

choose R2 = 1M

Ω to set the divider current at 1.5μA, and then calculate R1 using Equation 4:

(4)

Figure 16. TPS71401 Adjustable LDO Regulator Programming

8

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