LX1994

Microsemi

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 2

High Efficiency LED Driver

Copyright

© 2003

Rev. 1.0a, 2004-08-10

TM

®

ABSOLUTE MAXIMUM RATINGS

Supply Input Voltage (IN) ...................................................................-0.3V to 7V

SRC Input Current ......................................................................................600mA

Operating Temperature Range .........................................................-40°C to 85°C

Maximum Operating Junction Temperature ................................................ 150°C

Storage Temperature Range...........................................................-65°C to 150°C

Lead Temperature (Soldering 10 seconds) .................................................. 235°C

Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to

Ground. Currents are positive into, negative out of specified terminal

.

TH ERMAL DATA

THERMAL RESISTANCE

113

°C/W

THERMAL RESISTANCE

49

°C/W

above assume no ambient airflow.

PACKAGE PIN OUT

1

2

56

10

VIN

S/P

GND

DRV

8

OVP

9

SRC

3

BRT

FB

7

CMP

4

LS

(Top View)

1

2

3

4

56

7

8

9

10

VIN

S/P

BRT

LS

DRV

FB

OVP

SRC

GND

CMP

Connect Bottom to

Power GND

(Top View)

FUNCTIONAL PIN DESCRIPTION

Name

Description

IN

Unregulated IC Supply Voltage Input – Input range from 2.0V to 5.5V. Bypass with a 1

µF or greater capacitor for

operation below 2.0V.

GND

Common terminal for ground reference.

BRT

LED Current Adjustment - Accepts a DC analog input.

FB

LED Current Sense – Connect to current sense resistor.

SRC

MOSFET Current Sense Input - Connects to the external N-Channel MOSFET source.

DRV

MOSFET Gate Driver – Connects to an external N-Channel MOSFET gate.

OVP

Over Voltage Programming Pin – Connects to a resistor divider between the output load and GND to set the

maximum output voltage.

LS

Light Sensor Input – Allows light sensor current input to be modulated by the PWM control causing LED

brightness to be a product of the PWM duty cycle and ambient light level.

CMP

Compensation Pin – Apply a 0.1µF capacitor for loop compensation.

S/P

Shutdown/PWM Pin – A logic low longer than 100

µs causes the IC to enter Shutdown mode. Applying a PWM

signal to this pin and a filter capacitor to the BRT pin allows amplitude independent PWM control.