Micrel, Inc.

MIC2174/MIC2174C

September 2010

2

M9999-091310-C

Ordering Information

Part Number

Voltage

Accuracy

Switching Frequency

Junction Temperature

Range

Package

Lead Finish

MIC2174-1YMM

Adj.

±1%

300kHz

–40° to +125°C

10-Pin MSOP

Pb-Free

MIC2174C-1YMM

Adj.

±3%

270kHz

–40° to +125°C

10-Pin MSOP

Pb-Free

Pin Configuration

10-Pin MSOP (MM)

Pin Description

Pin Number

Pin Name

Pin Function

1

HSD

High-Side N-MOSFET Drain Connection (input): Power to the drain of the external high-side N-

channel MOSFET. The HSD operating voltage range is from 3V to 40V. Input capacitors between

HSD and the power ground (PGND) are required.

2

EN

Enable (input): A logic level control of the output. The EN pin is CMOS-compatible. Logic high or

floating = enable, logic low = shutdown. In the off state, supply current of the device is greatly reduced

(typically 0.8mA).

3

FB

Feedback (input): Input to the transconductance amplifier of the control loop. The FB pin is regulated

to 0.8V. A resistor divider connecting the feedback to the output is used to adjust the desired output

voltage.

4

GND

loop for the signal ground should be separate from the power ground (PGND) loop.

5

IN

Input Voltage (input): Power to the internal reference and control sections of the MIC2174/MIC2174C.

The IN operating voltage range is from 3V to 5.5V. A 2.2µF ceramic capacitors from IN to GND are

function behavior correctly.

6

DL

Low-Side Drive (output): High-current driver output for external low-side MOSFET. The DL driving

voltage swings from ground to IN.

7

PGND

Power Ground. PGND is the ground path for the MIC2174/MIC2174C buck converter power stage.

The PGND pin connects to the sources of low-side N-Channel MOSFETs, the negative terminals of

input capacitors, and the negative terminals of output capacitors. The loop for the power ground

should be as small as possible and separate from the Signal ground (GND) loop.

8

DH

High-Side Drive (output): High-current driver output for external high-side MOSFET. The DH driving

Adding a small resistor between DH pin and the gate of the high-side N-channel MOSFETs can slow

down the turn-on and turn-off time of the MOSFETs.