Micrel, Inc.

MIC22705

December 2010

2

M9999-121710-A

Ordering Information

Part Number

Voltage

Junction Temperature Range

Package

Lead Finish

MIC22705YML

Adjustable

–40°C to +125°C

24-Pin 4x4 MLF

®

Pb-Free

Note:

1. Other Voltage available. Contact Micrel for details.

Pin Configuration

24-Pin 4mm

Pin Description

Pin Number

Pin Name

Description

1, 6, 13, 18

PVIN

Power Supply Voltage (Input): The PVIN pins are the input supply to the internal P-Channel

Power MOSFET. A 22µF ceramic is recommended for bypassing at each PVIN pin. The SVIN

pin must be connected to a PVIN pin.

2

EN/DLY

Enable/Delay (Input): This pin is internally fed with a 1µA current source from SVIN. A delayed

turn on is implemented by adding a capacitor to this pin. The delay is proportional to the

capacitor value. The internal circuits are held off until EN/DLY reaches the enable threshold of

1.24V. This pin is pulled low when the input voltage is lower than the UVLO threshold.

3

DELAY

Delay (Input): Capacitor to ground sets internal delay timer. Timer delays Power Good (PG)

output at turn-on and ramp down at turn-off.

4

RC

Ramp Control: A capacitor from the RC pin-to-ground determines slew rate of output voltage

during start-up. The RC pin is internally fed with a 1µA current source. The output voltage tracks

the RC pin voltage. The slew rate is proportional by the internal 1µA source and RC pin

capacitor. This feature can be used for tracking capability as well as soft start.

5

PG

PG (Output): This is an open drain output that indicates when the output voltage is below 90% of

its nominal voltage. The PG flag is asserted without delay when the enable is set low or when the

output goes below the 90% threshold.

14

FB

Feedback: Input to the error amplifier. The FB pin is regulated to 0.7V. A resistor divider

connecting the feedback to the output is used to adjust the desired output voltage.