Micrel, Inc.

MIC4742

March 2009

3

M9999-030209-D

Pin Description

Pin Number

(MLF

Pin Number

(EPAD-TSSOP)

Pin Name

Pin Function

1

7

FB2

Feedback for output 2 (Input). Input to the error amplifier, connect to the

external resistor divider network to set the output voltage.

2

(1)

8

(1)

EN2

Enable for output 2 (Input). Logic level low, will shutdown the device, reducing

the current draw to less than 5µA (both EN1 and EN2 are low).

3,4

9,10

SW2

Switch for output 2 (Output): Internal power P-Channel MOSFET output switch

5

11

PGND2

Power Ground for output 2. Provides the ground return path for the high-side

drive current.

PGND1 pin and PGND2 pin are internally connected by anti-parallel diodes.

6,15

5,12

VIN2

Supply Voltage for output 2 (Input): Supply voltage for the source of the

internal P-channel MOSFET and driver. Requires bypass capacitor to GND.

VIN1 pins and VIN2 pins are internally connected by anti-parallel diodes.

7,14

4,13

VIN1

Supply Voltage for output 1 (Input): Supply voltage for the source of the

internal P-channel MOSFET and driver. Requires bypass capacitor to GND.

VIN1 pins and VIN2 pins are internally connected by anti-parallel diodes.

8

14

PGND1

Power Ground for output 1. Provides the ground return path for the

high-side drive current.

PGND1 pin and PGND2 pin are internally connected by anti-parallel diodes.

9,10

15,16

SW1

Switch for output 1 (Output): Internal power P-Channel MOSFET output switch

11

(1)

1

(1)

EN1

Enable for output 1 (Input). Logic level low, will shutdown the device, reducing

the current draw to less than 5µA (both EN1 and EN2 are low).

12

2

FB1

Feedback for output 1 (Input). Input to the error amplifier, connect to the

external resistor divider network to set the output voltage.

13

3

SGND

Signal (Analog) Ground. Provides return path for control circuitry and internal

reference.

16

6

BIAS

Internal circuit bias supply. Must be bypassed with a 0.1µF ceramic capacitor

to SGND. Biased through a 10

Ω resistor to VIN.

EPAD

EPAD

GND

Connect to ground.

Note:

1. Do not float Enable Input.