October 1998

5-169

MIC5021

Micrel

5

MIC5021

High-Speed High-Side MOSFET Driver

Ordering Information

Part Number

Temperature Range

Package

MIC5021BM

–40

°C to +85°C

8-pin SOIC

MIC5021BN

–40

°C to +85°C

8-pin Plastic DIP

Features

• 12V to 36V operation

• 550ns rise/fall time driving 2000pF

• TTL compatible input with internal pull-down resistor

• Overcurrent limit

• Gate to source protection

• Internal charge pump

• 100kHz operation guaranteed over full temperature and

operating voltage range

• Compatible with current sensing MOSFETs

• Current source drive reduces EMI

Applications

• Lamp control

• Heater control

• Motor control

• Solenoid switching

• Switch-mode power supplies

• Circuit breaker

General Description

The MIC5021 high-side MOSFET driver is designed to oper-

ate at frequencies up to 100kHz (5kHz PWM for 2% to 100%

duty cycle) and is an ideal choice for high speed applications

such as motor control, SMPS (switch mode power supplies),

and applications using IGBTs.

The MIC5021 can also

operate as a circuit breaker with or without automatic retry.

A rising or falling edge on the input results in a current source

pulse or sink pulse on the gate output. This output current

pulse can turn on a 2000pF MOSFET in approximately

550ns. The MIC5021 then supplies a limited current (< 2mA),

if necessary, to maintain the output state.

An overcurrent comparator with a trip voltage of 50mV makes

the MIC5021 ideal for use with a current sensing MOSFET.

An external low value resistor may be used instead of a

sensing MOSFET for more precise overcurrent control. An

optional external capacitor placed from the C

may be used to control the current shutdown duty cycle (dead

time) from 20% to < 1%. A duty cycle from 20% to about 75%

is possible with an optional pull-up resistor from C

The MIC5021 is available in 8-pin SOIC and plastic DIP

packages.

Other members of the MIC502x family include the MIC5020

low-side driver and the MIC5022 half-bridge driver with a

cross-conduction interlock.

Typical Application

Input

Gnd

Gate

Sense

Sense

TTL Input

N-Channel

Power MOSFET

+12V to +36V

MIC5021

1

2

3

4

8

7

6

5

10µF

2.7

nF

50mV

* increases time before retry

optional*

High-Side Driver with Overcurrent Trip and Retry