MIC38C42/3/4/5

Micrel, Inc.

September 2007

3

M9999-091107

Pin Description

Pin Number

Pin Number

Pin Name

Pin Function

N, M, MM

-1BN, -1BM

1

1

COMP

Compensation: Connect external compensation network to modify the error

amplifier output.

2

NC

Not internally connected.

2

3

FB

Feedback (Input): Error amplifier input. Feedback is 2.5V at desired output

voltage.

4

NC

Not internally connected.

3

5

ISNS

Current Sense (Input): Current sense comparator input. Connect to current

sensing resistor or current transformer.

6

NC

Not internally connected.

4

7

RT/CT

Timing Resistor/Timing Capacitor: Connect external RC network to select

switching frequency.

5

GND

Ground: Combined analog and power ground.

8

PGND

Power Ground: N-channel driver transistor ground.

9

AGND

Analog Ground: Controller circuitry ground.

6

10

OUT

Power Output: Totem-pole output.

11

VD

Power Supply (Input): P-channel driver transistor supply input. Return to

power ground (PGND).

7

12

VDD

Analog Supply (Input): Controller circuitry supply input. Return to analog

ground (AGND).

13

NC

Not internally connected.

8

14

VREF

5V Reference (Output): Connect external RC network.

1

2

3

4

8

7

6

5

COMP

FB

ISNS

RT/CT

VREF

VDD

OUT

GND

MIC38C4x

2

NC

NC

13

3

FB

VDD

12

4

NC

VD

11

5

ISNS

OUT

10

6

NC

AGND

9

7

RT/CT

PGND

8

1

COMP

V R E F

14

MIC38C4x-1

8-Pin DIP (N)

8-Pin SOIC (M)

8-Pin MSOP (MM)

14-Pin DIP (-1BN)

14-Pin SOIC (-1BM)

Pin Configuration