MIC22705

1MHz, 7A Integrated Switch High-Efficiency

Synchronous Buck Regulator

Ramp Control is a trademark of Micrel, Inc

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

General Description

The Micrel MIC22705 is a high-efficiency, 7A integrated

switch synchronous buck (step-down) regulator. The

MIC22705 is optimized for highest efficiency, achieving

more than 95% efficiency while still switching at 1MHz.

The ultra-high speed control loop keeps the output voltage

within regulation even under the extreme transient load

swings commonly found in FPGAs and low-voltage ASICs.

The output voltage is pre-bias safe and can be adjusted

down to 0.7V to address all low-voltage power needs.

The MIC22705 offers a full range of sequencing and

tracking options. The Enable/Delay (EN/DLY) pin,

combined with the Power Good (PG) pin, allows multiple

outputs to be sequenced in any way during turn-on and

turn-off. The Ramp Control™ (RC) pin allows the device to

be connected to another product in the MIC22xxx and/or

MIC68xxx family, to keep the output voltages within a

certain ∆V on start-up.

The MIC22705 is available in a 24-pin 4mm x 4mm MLF

®

with a junction operating range from –40

°C to +125°C.

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

• Input voltage range: 2.9V to 5.5V

• Output voltage adjustable down to 0.7V

• Output load current up to 7A

• Safe start-up into a pre-biased output load

• Full sequencing and tracking capability

• Power Good output

• Efficiency >95% across a broad load range

• Ultra-fast transient response

• Easy RC compensation

• 100% maximum duty cycle

• Fully-integrated MOSFET switches

• Thermal-shutdown and current-limit protection

• –40°C to +125°C junction temperature range

Applications

• High power density point-of-load conversion

• Servers, routers, and base stations

• DVD recorders / Blu-ray players

• Computing peripherals

• FPGAs, DSP and low-voltage ASIC power

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Typical Application

MIC22705 7A 1MHz Synchronous Output Converter

vs. Output Current

50

55

60

65

70

75

80

85

90

95

100

0123

456

7

OUTPUT CURRENT (A)

2.5V

3.3V

March 2011

M9999-033111-A