January 2005

1

M0512-112603

MIC2042/2043

Micrel

MIC2042/2043

Single Channel, High Current, Low Voltage,

Protected Power Distribution Switch

General Description

The MIC2042 and MIC2043 are high-side MOSFET switches

optimized for general purpose power distribution applications

which require circuit protection. The devices switch up to 5.5V

and as low as 0.8V while offering both programmable current

limiting and thermal shutdown to protect the device and the

load. A fault status output is provided in order to detect

overcurrent and thermal shutdown fault conditions. Both

devices employ soft-start circuitry to minimize the inrush

current in applications that employ highly capacitive loads.

Additionally, for tighter control over inrush current during

start-up, the output slew-rate may be adjusted by an external

capacitor.

The MIC2043 features a auto-reset circuit breaker mode that

latches the output off upon detecting an overcurrent condition

lasting more than 28ms. The output is reset by removing or

reducing the load.

All support documentation can be found on Micrel’s web

site at www.micrel.com.

Typical Application

Features

• 60mΩ max. on-resistance

• 0.8V to 5.5V operating range

• Adjustable current limit

• Power-Good detection

• Up to 3A continuous output current

• Short-circuit protection with thermal shutdown

• Adjustable slew-rate control

• Circuit breaker mode (MIC2043)

• Fault status flag

• Undervoltage lockout

• Output MOSFET reverse current flow block when

disabled

• Very fast reaction to short-circuits

• Low quiescent current

Applications

• Docking stations

• Notebook PCs

• PDAs

• Hot swap board insertions

• RAID controllers

• USB hosts

• ACPI power distribution

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

8, 12

7

2

3

6

9

13

10,11,14

1

4

200Ω

Note:

All V

All V

I

Output Power-Good = 3.0V.

*C4 is optional. See "Applications Information."

C4*

0.022µF

C1

0.1µF

Logic

Controller

ON/OFF

OVERCURRENT

IN

5

MIC2042-1BTS

MIC39100-2.5BS

VBIAS

VIN

EN

/FAULT

ILIM

SLEW

2.5V

VOUT

PGREF

PWRGD

UVLOIN

GND

+3.3V

Power

Supply

R1

20kΩ

R4

20kΩ

R2

1%

R3

1%

EN

IN

GND

OUT

(OPEN)

3.3V@ 1.5A

OUT1

OUT2

C2

0.1µF

C3

4.7µF