May 2002

1

MIC2185

MIC2185

Micrel

MIC2185

Low Voltage Synchronous Boost PWM Control IC

Final Information

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 5

Ω 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 syn-

chronized drive, the MIC2185 is ideal for noise-sensitive

telecommunications applications. The nominal 400kHz oper-

ating 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 efficien-

cies 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)

2.4

µH

8m

Ω

70

75

80

85

90

95

100

012

34

5

OUTPUT CURRENT (A)

5V Output Efficiency

V

200kHz PWM

Adjustable Output Synchronous Boost Converter

Features

• Input voltage range: 2.9V to 14V

• 95% efficiency

• Oscillator frequency of 200kHz/400kHz

• Frequency sync to 600kHz

• 0.5

µA shutdown current

• Two 5

Ω 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 and 16 pin QSOP

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. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

Ordering Information

Part Number

Frequency Voltage

Junction Temp. Range

Package

MIC2185BM

200/400kHz

Adj

–40

°C to +125°C

16-lead SOP

MIC2185BQS

200/400kHz

Adj

–40

°C to +125°C

16-lead QSOP