MIC2179

Micrel

MIC2179

2

June 1998

Pin Description

Pin Number

Pin Name

Pin Function

1, 2, 19, 20

PGND

Power Ground: Connect all pins to central ground point.

3

SW

Switch (Output): Internal power MOSFET output switches.

5

PWM

PWM/Skip-Mode Control (Input): Logic-level input. Controls regulator

operating mode. Logic low enables PWM mode. Logic high enables skip

mode. Do not allow pin to float.

6

PWRGD

Error Flag (Output): Open-drain output. Active low when FB input is 10%

below the reference voltage (V

7

FB

Feedback (Input): Connect to output voltage divider resistors.

8

COMP

Compensation: Output of internal error amplifier. Connect capacitor or

series RC network to compensate the regulator control loop.

9–12

SGND

Signal Ground: Connect all pins to ground, PGND.

13

SYNC

Frequency Synchronization (Input): Optional. Connect an external clock

signal to synchronize the oscillator. Leading edge of signal above 1.7V

terminates switching cycle. Connect to SGND if not used.

14

BIAS

Internal 3.3V Bias Supply: Decouple with 0.01

µF bypass capacitor to

SGND. Do not apply any external load.

15

EN

Enable (Input): Logic high enables operation. Logic low shuts down

regulator. Do not allow pin to float.

16, 17

VIN

Supply Voltage (Input): Requires bypass capacitor to PGND. Both pins

must be connected to V

4, 18

NC

not internally connected.

Pin Configuration

2

PGND

3

SW

4

NC

5

PWRGD 6

PWM

7

FB

1

PGND

8

COMP

9

SGND

PGND

20

PGND

19

NC

18

VIN

17

VIN

16

EN

15

10

SGND

14

13

12

11 SGND

SGND

SYNC

BIAS

20-Lead Wide SSOP

Ordering Information

Part Number

Voltage

Temperature Range

Package

MIC2179BSM

Adjustable

–40

°C to +85°C

20-lead SSOP

MIC2179-3.3BSM

3.3V

–40

°C to +85°C

20-lead SSOP

MIC2179-5.0BSM

5.0V

–40

°C to +85°C

20-lead SSOP