September 1999

179

MIC5022

MIC5022

Micrel

Pin Description

DIP Pin No.

SOIC Pin No.

Pin Name

Pin Function

11

V

DD

Supply: +12V to +36V. Decouple with

≥ 10µF capacitor.

2

3

Input

TTL Compatible Input: Logic high turns the high-side external MOSFET on

and the low-side external MOSFET off. Logic low turns the high-side

external MOSFET off and the low-side external MOSFET on. An internal

pull-down returns an open pin to logic low.

3

4

Fault

When either sense voltage exceeds threshold, open collector output is open

circuit for 5

µs (t

C

45

C

TH

Retry Trimming Capacitor, High Side: Controls the off time (t

overcurrent retry cycle. (Duty cycle adjustment.)

• Open = approx. 20% duty cycle.

• Capacitor to Ground = approx. 20% to < 1% duty cycle.

• Pullup resistor = approx. 20% to approx. 75% duty cycle.

• Ground = maintained shutdown upon overcurrent condition.

5

6

Enable

Output Enable: Disables operation of the output drivers; active high. An

internal pull-down returns an open pin to logic low.

67

C

TL

Retry Trimming Capacitor, Low Side: Same function as C

7

8

Gnd

Circuit Ground

8

8

Sense L +

Current Sense Comparator (+) Input, Low Side: Connect to source of low-

side MOSFET. A built-in offset (nominal 50mV) in conjunction with R

SENSE

sets the load overcurrent trip point.

9

10

Sense L –

Current Sense Comparator (–) Input, Low Side: Connect to the negative

side of the low-side sense resistor.

10

11

Gate L

Gate Drive, Low Side: Drives the gate of an external power MOSFET. Also

limits V

source current.

11

12

Sense H +

Current Sense Comparator (+) Input, High Side: Connect to source of high-

side MOSFET. A built-in offset (nominal 50mV) in conjunction with R

SENSE

sets the load overcurrent trip point.

12

13

Source H –

Current Sense Comparator (–) Input, High Side: Connect to the negative

side of the high-side sense resistor.

13

14

Gate H

Gate Drive, High Side: Drives the gate of an external power MOSFET. Also

limits V

source current.

14

15

V

BOOST

Charge Pump Boost Capacitor: A bootstrap capacitor from V

MOSFET source pin supplies charge to quickly enhance the external

MOSFET’s gate .

Pin Configuration

DIP Package

SOIC Package

(N)

(WM)

114

2

3

4

5

6

7

13

12

10

9

8

11

Input

Fault

Enable

Gnd

Gate H

Sense H–

Sense H+

Gate L

Sense L–

Sense L+

1

14

2

3

4

5

6

7

13

12

10

9

11

Input

Fault

Enable

Gnd

Gate H

Sense H–

Sense H+

Gate L

Sense L–

Sense L+

NC

NC

8

15

16