October 2005

1

MIC2185

MIC2185

Micrel, Inc.

MIC2185

Low Voltage Synchronous Boost PWM Control IC

General Description

Micrel’s MIC2185 is a high efficiency synchronous boost

PWM control IC. With its wide input voltage range of 2.9V to

14V, the MIC2185 can be used to efficiently boost voltages

in 1- or 2-cell Li Ion battery powered applications, as well as

fixed 3.3V and 5V systems. Its powerful 5Ω output drivers

allow the MIC2185 to supply large output currents with the

selection of the proper external MOSFETs.

With it’s fixed frequency PWM architecture, and easily

synchronized drive, the MIC2185 is ideal for noise-sensi-

tive telecommunications applications. The nominal 400kHz

operating frequency of the MIC2185 can be divided by two,

allowing the device to be externally synchronized to frequen-

cies below 400kHz.

The MIC2185 also features a low current shutdown mode

and a programmable undervoltage lockout. A skipped pulse

mode of operation can be manually set to achieve higher

efficiencies at light load conditions.

The MIC2185 is available in a 16 pin SOIC package and 16

pin QSOP package with an ambient temperature operating

range from –40°C to 85°C.

Typical Application

VINA

EN/UVLO

FREQ/2

VDD

COMP

VREF

SYNC

SKIP

SS

MIC2185

SGND

OUTP

VINP

FB

OUTN

CSH

PGND

5

12

9

13

6

16

14

3

2

11

8

4

10

15

7

1

Si9803DY (x2)

Si4884DY (x2)

2.4µH

8m

70

75

80

85

90

95

100

0

1

2

3

4

5

OUTPUT CURRENT (A)

5V Output Efficiency

200kHz P WM

Adjustable Output Synchronous Boost Converter

Features

• Input voltage range: 2.9V to 14V

• 95% efficiency

• Oscillator frequency of 200kHz/400kHz

• Frequency sync to 600kHz

• 0.5µA shutdown current

• Two 5Ω output drivers

• Front edge blanking

• PWM current mode control

• Cycle-by-cycle current limiting

• Frequency foldback protection

• Adjustable under-voltage lockout

• Precision 1.245V reference output

• 16 pin SOIC narrow body package

Applications

• 3.3V to 5V conversion in telecom systems

• Satellite phones

• Cable modems

• 1-and 2-cell Li Ion battery operated equipment

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

Ordering Information

Part Number

Frequency

Voltage

Junction

Temp. Range

Package

Standard

Pb-Free

MIC2185BM

MIC2185YM

200/400kHz

Adj

–40ºC to +125ºC

16-pin SOIC

MIC2185BQS

MIC2185YQS

200/400kHz

Adj

–40ºC to +125ºC

16-pin QSOP