October 2005

9

M9999-101705

MIC2213

Micrel, Inc.

Functional Diagram

OUT1

OUT2

POR

DRV

NGND

GND

SW

CBYP

SET

EN

VIN

LDO1

LDO2

Reference

Delay

MIC2213 Fixed Voltage Block Diagram

OUT1

OUT2

POR

DRV

NGND

GND

SW

CBYP

SET

EN

VIN

ADJ2

ADJ1

LDO1

LDO2

Reference

Delay

MIC2213 Adjustable Voltage Block Diagram

Functional Description

The MIC2213 is a high performance, low quiescent current

power management IC consisting of two µCap low dropout

regulators, a power-on reset (POR) circuit and an open-drain

driver. The first regulator is capable of sourcing 150mAat out-

putvoltagesfrom1.25Vto5V.Thesecondregulatoriscapable

of sourcing 300mA of current at output voltages from 1.25V

to 5V. The second regulator has a POR circuit that monitors

its output voltage and indicates when the output voltage is

within 5% of nominal. The POR offers a delay time that is

externally programmable with a single capacitor to ground.

An open-drain driver completes the power management

chipset, offering the capability of driving LEDs for keypad

backlighting in applications such as cellphones.

Enable

The enable input allows for logic control of both output volt-

ages with one enable input. The enable input is active high,

requiring 1.8V for guaranteed operation. The enable input is

CMOS logic and cannot by left floating.

Power-On Reset (POR)

The power-on reset output is an open-drain N-channel de-

vice, requiring a pull-up resistor to either the input voltage

or output voltage for proper voltage levels. The POR output

has a delay time that is programmable with a capacitor from

the SET pin to ground. The delay time can be programmed

to be as long as 1 second.

The SET pin is a current source output that charges a ca-

pacitor that sets the delay time for the power-on reset output.

The current source is a 1µA current source that charges a

capacitor up from 0V. When the capacitor reaches 1.25V, the

output of the POR is allowed to go high.

Open-Drain Driver (DRV)

The drive (DRV) pin is an open-drain output capable of sinking

150mA of current. This output is controlled by a logic level

input, the switch (SW) pin. The switch pin is an active high

input and cannot be left floating.