Micrel, Inc.

MIC22950

February 2010

2

M9999-021910-B

Ordering Information

Part Number

Nominal Output Voltage

Temperature Range

Package

Lead Finish

MIC22950YML

Adjustable

−40° to +125°C

32-Pin 5mm x 5mm MLF

®

Lead Free

Note:

MLF

Pin Configuration

32-Pin 5mm x 5mm MLF

Pin Description

Pin Number

Pin Name

Pin Function

1,2,7,8,17,23,24

PVIN

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

3

EN/DLY

Enable/ delay (Input): This pin has a 1.24V band gap reference. When the pin is pulled higher

that this the part will start up. Below this voltage the device is in its low quiescent current mode.

The pin has a 1µA current source pull-up to VIN. By adding a capacitor to this pin, a delay may

be generated. The enable function will not operate with an input voltage lower than UVLO.

4

DELAY

Delay (Input): A capacitor sets the internal delay timer. Timer delays power-on reset (POR) at

power-up and power-down.

5

RC

Ramp Control (Input): Capacitor-to-ground from this pin determines slew rate of output voltage

during start-up. This can be used for tracking capability as well as soft start. RC pin cannot be

left floating. Use a minimum capacitor value of 120pF or larger.

6

POR/PG

Power-On-Reset (Output): Open-drain output device indicates when the output is out of

regulation and is active after the delay set by the DELAY pin.

9,10,15,16,25,26,

31,32

PGND

Power Ground (Power): Power Ground.

11,12,13,14,27,

28,29,30

SW

Switch (Output): Internal power MOSFET output switches.

18

SGND

Signal Ground (Signal): Signal Ground.

19

CF

Frequency Set (Input): Adjustable Frequency with external capacitor.

20

FB

Feedback (Input): Input to the error amplifier, connect to the external resistor divider network to

set the output voltage.

21

COMP

Compensation pin (Input): Place a RC-to-SGND to compensate the device, see applications

section.

22

SVIN

Signal Power Supply Voltage (Input): Requires bypass capacitor-to-SGND.

EP

GND

Center Tab (Power): Must make a full connection to a GND plane for full output power to be

realized.