Micrel, Inc.

MIC3205

October 2012

2

M9999-102312-A

Ordering Information

Part Number

Junction Temperature Range

Package

(1)

MIC3205YML

40°C to 125°C

10-Pin 3mm x 3mm MLF

Note:

1.

MLF is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.

Pin Configuration

10-Pin 3mm x 3mm MLF (ML)

Top View

Pin Description

Pin Number

Pin Name

Pin Function

1

VCC

Voltage Regulator Output. The VCC pin is the output of a linear regulator powered from VIN, which

supplies power to the internal circuitry. A 4.7µF ceramic capacitor is recommended for bypassing. Place

it as close as possible to the VCC and AGND pins. Do not connect to an external load.

2

CS

Current Sense Input. Negative input to the current sense comparator. Connect an external sense

resistor to set the LED current. Connect the current sense resistor as close as possible to the chip.

3

VIN

Input Power Supply. VIN is the input supply pin to the internal circuitry. Due to high frequency switching

noise, a 10µF ceramic capacitor is recommended for bypassing and should be placed as close as

possible to the VIN and PGND pins. See “PCB Layout Guidelines.”

4

VINS

VIN Sense. Positive input to the current sense comparator. Connect as close as possible to the current

sense resistor.

5

AGND

Analog Ground. Ground for all internal low-power circuitry.

6

EN

Enable Input. Logic high (greater than 2V) powers up the regulator. A logic low (less than 0.4V) powers

down the regulator and reduces the supply current of the device to less than 2µA. A logic low pulls down

the DRV pin turning off the external MOSFET. Do not drive the EN pin above VIN. Do not leave floating.

7

DIM

PWM Dimming Input. A PWM input can be used to control the brightness of the LED. Logic high (greater

than 2V) enables the output. Logic low (less than 0.4V) disables the output regardless of the EN state.

Do not drive the DIM pin above VIN. Do not leave floating.

8

CTIMER

Timer Capacitor. A capacitor is required from CTIMER to ground sets the target switching frequency

9

PGND

Power Ground. Ground for the power MOSFET gate driver. The current loop for the power ground

should be as small as possible and separate from the analog ground loop. See “PCB Layout

Recommendations.”

10

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.

EP

ePAD

Exposed Pad. Must be connected to a GND plane for best thermal performance.