MIC2811/2821

Digital Power Management IC

2MHz, 600mA DC/DC with

Triple 300mA LDOs

Micro

LeadFrame and MLF are registered trademarks of Amkor Technology, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

April 2008

M9999-042208-A

General Description

The

MIC2811/21

are

high

performance

power

management ICs, supporting four output voltage rails with

maximum efficiency. The four rails are generated by a

single 600mA DC/DC converter and three 300mA LDOs.

LDO1 and LDO2 are capable of operating at a low input

voltage down to 1.65V useful for post regulating the output

voltage of the DC-DC converter. The MIC2811 supports

the use of a bypass cap for improved noise performance

on LDO1 & LDO2 while the MIC2821 offers a separate

enable pin for LDO3.

Featuring an operating frequency of 2MHz, the DC to DC

converter uses small values of L and C to reduce board

space but still retains operating efficiencies up to 86% at

load currents up to 600mA.

The MIC2811/21 feature a µCap design, operating with

very small ceramic output capacitors and inductors for

stability, reducing required board space and component

cost and it is available in fixed output voltages in the 16-

pin 3mm × 3mm MLF

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Applications

•

Mobile phones / PDAs

•

Portable media players

•

Mobile Television Receivers

Features

•

2MHz DC/DC converter and 3 LDOs

•

Tiny 16-pin 3mm x 3mm MLF

•

Thermal Shutdown Protection

•

±2% Output Voltage Accuracy on all outputs

•

Current Limit Protection

DC/DC Converter

•

2.7V to 5.5V input voltage range

•

Output current to 600mA

•

2MHz PWM operation

•

Up to 86% efficiency (1.2V output)

LDO 1 & 2

•

1.65V to 5.5V input voltage range

•

300mA output current

•

Fixed Output voltage as low as 0.8V

•

Low 142mV dropout

•

70dB PSRR at 1kHz

LDO 3

•

2.7V to 5.5V input voltage range

•

300mA output current

•

Fixed Output voltage as low as 1.0V

____________________________________________________________________________________________________________

Typical Application

0

10

20

30

40

50

60

70

80

90

100

0

100 200 300 400 500 600

OUTPUT CURRENT (mA)

1.2VOUT Efficiency

L = 2.2µH

C = 2.2µF

3V

3.6V

4.2V