MIC94325/45/55

500mA LDO with

Ripple Blocker

 Technology

Ripple Blocker is a trademark of Micrel, Inc

General Description

The MIC943x5 Ripple Blocker

 is a monolithic integrated

circuit that provides low-frequency ripple attenuation

(switching noise rejection) to a regulated output voltage.

This is important for applications where a DC/DC switching

converter is required to lower or raise a battery voltage but

where switching noise cannot be tolerated by sensitive

downstream circuits such as in RF applications. The

MIC943x5 maintains high power supply ripple rejection

(PSRR) with input voltages operating near the output

voltage level to improve overall system efficiency. A low-

voltage logic enable pin facilitates ON/OFF control at

typical GPIO voltage levels.

The MIC943x5 operates from an input voltage of 1.8V to

3.6V. The MIC943x5 options include fixed (MIC94345/55)

or adjustable (MIC94325) output voltages. The MIC94355

version offers an auto-discharge to discharge the output

capacitor when the part is disabled.

Packaged in a 0.84mm x 1.32mm 6-ball CSP or a 6-pin

1.6mm x 1.6mm Thin DFN, the MIC943x5 has a junction

operating temperature range of –40

C to +125C.

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

 1.8V to 3.6V input voltage range

 Active noise rejection over a wide frequency band



>50dB from 10Hz to 5MHz at 500mA load

 Rated to 500mA output current

 Fixed and adjustable output voltages

 Optional output auto-discharge when disabled

 Current-limit and thermal-limit protected

 Ultra-small 0.84mm x 1.32mm 6-ball CSP

 1.6mm x 1.6mm, 6-pin Thin DFN

 Logic-controlled enable pin

 40C to +125C junction temperature range

Applications

 Smart phones

 Tablet PC/notebooks and webcams

 Digital still and video cameras

 Global positioning systems

 Mobile computing

 Automotive and industrial applications

_________________________________________________________________________________________________

Typical Application

October 2012

M9999-102512-A

MIC94355 PSRR

-120

-100

-80

-60

-40

-20

0

10

100

1,000 10,000 100,00

0

1,000,0

00

10,000,

000

FREQUENCY (Hz)

10

100

1K

10K

100K

1M

10M

10mA

200mA

500mA