MP8802 – LOW DROPOUT, 250mA LINEAR REGULATOR
MP8802 Rev. 1.4 www.MonolithicPower.com 5
10/10/2011 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
PIN FUNCTIONS
Pin # Name Description
1 IN
Power Source Input. IN supplies the internal power to the MP8802 and is the source of the
pass transistor. Bypass IN to GND with a 1F or greater capacitor.
2 GND Ground.
3 EN
Enable Input. Drive EN high to turn on the MP8802, drive EN 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. OUT feedback threshold is 1.222V.
5 OUT
Regulator Output. OUT is the output of the linear regulator. Bypass OUT to GND with a
1F or greater capacitor.
OPERATION
The MP8802 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 MP8802 uses a PMOS pass
element and features internal thermal shutdown.
As shown in Figures 1 and 2, optional feed-
forward capacitor C
BYP
may be added between
FB and OUT pins for an improved transient
response.
MP8802_F01_BD01
V
IN
V
EN
C
OUT
GND
FB
OUT
V
OUT
--
+
BANDGAP
REFERENCE
INTERNAL
RESISTOR
DIVIDER
C
BYP
Figure 1—Ultra-Low-Noise Fixed Output Regulator
MP8802_F02_BD02
V
IN
V
EN
C
OUT
C
BYP
R1
R2
V
OUT
--
+
BANDGAP
REFERENCE
GND
FB
OUT
EXTERNAL
RESISTOR
DIVIDER
Figure 2—Ultra-Low-Noise Adjustable Regulator: V
OUT
= V
FB
(1+(R1/R2))
