IN

OUT

FB

GND

SHDN

TPS73801

Load

IN

OUT

FB

GND

2.5 V at 1 A

SHDN

TPS73801

10 µF

(ceramic)

10 µF

(ceramic)

4.22 kW

4.0 kW

TPS73801

www.ti.com

SLVS915A – FEBRUARY 2010 – REVISED JULY 2012

APPLICATION INFORMATION

The TPS73801 is a 1.0-A LDO regulator optimized for fast transient response. The devices are capable of

supplying 1.0 A at a dropout voltage of 300 mV. The low operating quiescent current (1 mA) drops to less than

1 µA in shutdown. In addition to the low quiescent current, the TPS73801 regulators incorporate several

protection features which make them ideal for use in battery-powered systems. The devices are protected

against both reverse input and reverse output voltages. In battery-backup applications where the output can be

held up by a backup battery when the input is pulled to ground, the TPS73801 acts as if it has a diode in series

with its output and prevents reverse current flow. Additionally, in dual-supply applications where the regulator

load is returned to a negative supply, the output can be pulled below ground by as much as 20 V and still allow

the device to start and operate.

Typical Applications

Figure 24. 3.3 V to 2.5 V Regulator

Figure 25. Kelvin Sense Connection

Adjustable Operation

The TPS73801 has an output voltage range of 1.21 V to 20 V. The output voltage is set by the ratio of two

external resistors as shown in Figure 26. The device maintains the voltage at the FB pin at 1.21 V referenced to

ground. The current in R1 is then equal to 1.21 V / R1, and the current in R2 is the current in R1 plus the FB pin

bias current. The FB pin bias current, 3 µA at 25°C, flows through R2 into the FB pin. The output voltage can be

calculated using the formula shown in Figure 26. The value of R1 should be less than 4.17 k

Ω to minimize errors

in the output voltage caused by the FB pin bias current. Note that in shutdown the output is turned off, and the

divider current is zero.

Copyright © 2010–2012, Texas Instruments Incorporated

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Product Folder Link(s): TPS73801