MP8801 – LOW DROPOUT, 150mA LINEAR REGULATOR

MP8801 Rev. 1.6

www.MonolithicPower.com

4

3/6/2006

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© 2006 MPS. All Rights Reserved.

PIN FUNCTIONS

Pin #

Name

Description

1

IN

Power Source Input. IN supplies the internal power to the MP8801 and is the source of the

pass transistor. Bypass IN to GND with a 1µF or greater capacitor.

2

GND

Ground.

3

EN

Enable Input. Drive EN high to turn on the MP8801; low to turn it off. For automatic startup,

connect EN to IN.

4

FB

Feedback Input. Connect a resistive voltage divider from OUT to FB to set the output

voltage. The OUT feedback threshold is 1.222V.

5

OUT

Regulator Output. OUT is the output of the linear regulator. Bypass OUT to GND with a

1µF or greater capacitor.

OPERATION

The MP8801 is a low-current, low-noise,

high-PSRR, low-dropout linear regulator. It is

intended for use in devices that require very low

noise power supplies and high-PSRR such as

PLL VCO supplies for mobile handsets and

802.11 PC Cards, as well as audio codecs and

microphones. The MP8801 uses a PMOS pass

element and features internal thermal shutdown.

The normally fixed output MP8801 may be

converted to an adjustable output device by

applying a resistor divider network as shown in

Figure 2. An optional feed-forward capacitor,

response.

MP8801_F01_BD01

C3

GND

FB

OUT

--

+

BANDGAP

REFERENCE

INTERNAL

RESISTOR

DIVIDER

Figure 1—Ultra-Low-Noise Fixed Output Regulator

MP8801_F02_BD02

R1

R2

--

+

BANDGAP

REFERENCE

GND

FB

OUT

EXTERNAL

RESISTOR

DIVIDER