Micrel, Inc.

MIC3203

March 2010

2

M9999-032910-A

Part Number

Marking

Junction Temperature Range

Package

PWM

MIC3203YM

MIC3203YM

−40°C to +125°C

8-Pin SOIC

Dither

MIC3203-1YM

MIC3203-1YM

−40°C to +125°C

8-Pin SOIC

Non-Dither

Note:

1. YM

Pin Configuration

8-Pin SOIC

MIC3203/MIC3203-1

Pin Description

Pin Number

Pin Name

Pin Function

1

VCC

of a linear regulator which is powered from VIN. A 1µF ceramic capacitor is recommended for bypassing

and should be placed as close as possible to the VCC and AGND pins. Do not connect to an external

load.

2

CS

Current-Sense Input. The CS pin provides the high-side current sense to set the LED current with an

external sense resistor.

3

VIN

Input Power Supply. VIN is the input supply pin to the internal circuitry and the positive input to the

current sense comparator. Due to the high frequency switching noise, a 10µF ceramic capacitor is

recommended to be placed as close as possible to VIN and the power ground (PGND) pin for

bypassing. Please refer to layout recommendations.

4

AGND

Ground pin for analog circuitry. Internal signal ground for all low power sections.

5

EN

Enable Input. The EN pin provides a logic level control of the output and the voltage has to be 2.0V or

higher to enable the current regulator. The output stage is gated by the DIM pin. When the EN pin is

pulled low, the regulator goes to off state and the supply current of the device is greatly reduced (below

1µA). In the off state, during this period the output drive is placed in a "tri-stated" condition, where

MOSFET is in an “off” or non-conducting state. Do not drive the EN pin above the supply voltage.

6

DIM

PWM Dimming Input. The DIM pin provides the control for brightness of the LED. A PWM input can be

used to control the brightness of LED. DIM high enables the output and its voltage has to be at least

2.0V or higher. DIM low disables the output, regardless of EN “high” state.

7

PGND

Power Ground Pin for Power FET. Power Ground (PGND) is for the high-current switching with

hysteretic mode. The current loop for the power ground should be as small as possible and separate

from the Analog ground (AGND) loop. Refer to the layout considerations for more details.

8

DRV

Gate-Drive Output. Connect to the gate of an external N-channel MOSFET. The drain of the external

MOSFET connects directly to the inductor and provides the switching current necessary to operate in

hysteretic mode. Due to the high frequency switching and high voltage associated with this pin, the

switch node should be routed away from sensitive nodes.