Micrel, Inc.

MIC2225

February 2008

3

M9999-022008-D

Pin Description

Pin Number

Pin Name

Pin Function

1

AGND

Analog (signal) Ground.

2

LDO

LDO Output (Output): Connect to a 2.2µF output capacitor.

3

BIAS

Internal circuit bias supply. Must be de-coupled to signal ground with a 0.1µF

capacitor and should not be loaded.

4

AVIN

Analog Supply Voltage (Input): Supply voltage for the analog control circuitry

and LDO input power. Requires bypass capacitor to GND. It must be tied to

VIN.

5

FB

Feedback. Input to the error amplifier. For the Adjustable option, connect to the

external resistor divider network to set the output voltage. For fixed output

voltage.

6

EN

Enable (Input). Logic low will shut down the switching regulator reducing the

quiescent current to less than 5µA.

7

ENLDO

Enable LDO (Input): Logic low will shut down the LDO, reducing the quiescent

current to less than 5µA.

8

VIN

Supply Voltage (Input): Supply voltage for the internal switches and drivers.

9

SW

Switch (Output): Internal power MOSFET output switches.

10

PGND

Power Ground.