Data Sheet

Servo
Error
Amp
Ref
27 k
W
8 k
W
Current
Limit
Thermal
Protection
Bandgap
NR
OUT
R
1
R
2
EN
GND
IN
R
1
+ R
2
= 80 k
W
4-MHZ
Charge Pump
TPS731
www.ti.com SBVS034N –SEPTEMBER 2003–REVISED DECEMBER 2015
7 Detailed Description
7.1 Overview
The TPS731xx family of low-dropout linear regulators operates down to an input voltage of 1.7 V and supports
output voltages down to 1.2 V while sourcing up to 150 mA of load current. This linear regulator uses an NMOS
pass element with an integrated 4-MHz charge pump to provide a dropout voltage of less than 100 mV at full
load current. This unique architecture also permits stable regulation over a wide range of output capacitors. In
fact, the TPS731xx family of devices does not require any output capacitor for stability. The increased
insensitivity to the output capacitor value and type makes this family of linear regulators an ideal choice when
powering a load where the effective capacitance is unknown.
The TPS731xx family of devices also features a noise reduction (NR) pin that allows for additional reduction of
the output noise. With a noise reduction capacitor of 0.01 µF connected from the NR pin to GND, the TPS73115
output noise can be as low as 12.75 µV
RMS
. The low noise output featured by the TPS731xx family makes it well-
suited for powering VCOs or any other noise sensitive load.
7.2 Functional Block Diagrams
Figure 29. Fixed-Voltage Version
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