LX1996

Microsemi

Analog Mixed Signal Group

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

Page 2

Copyright

© 2007

Rev. 1.0, 2007-12-14

Multi-string LED Back-light Controller

TM

®

ABSOLUTE MAXIMUM RATINGS

PACKAGE PIN OUT

Supply Input Voltage (VIN), EN ........................................................................-0.3V to 30V

CS# pins ..............................................................................................................-0.3V to 28V

DSEL1, DSEL2, DI and PWM pins ..................................................................-0.3V to 6.0V

CS# Current ................................................................................................................... 35mA

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

°C

Maximum Operating Junction Temperature ...................................................................150

°C

Storage Temperature Range............................................................................. -65

°C to 150°C

Package Peak Temp. for Solder Reflow (40 seconds maximum exposure) ....... 260°C (+0 -5)

Notes: 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.

Solder reflow to follow: IPC/JEDEC J-STD-020B 7/02 Pb-Sn Small Body Profile

DSEL2

DSEL1

MSC

LX1996

XXXX

CS1

CS2

CS4

CS5

CS6

1

2

3

4

7

8

9

10

15

16

17

18

21

22

23

24

Connect Bottom

Pad to GND

14

11

20

5

VLDO

CS3

EN

6

12

13

19

DI

OT

(Top View)

RoHS / Pb-free 100% Matte Tin pin Finish

XXXX = Date code / Lot code identifier

FUNCTIONAL PIN DESCRIPTION

Name

Pin #

Description

EN

1

Enable Input - Logic input. Pull low to put the system into sleep mode; If not used must be tied to VIN.

VLDO

2

Internal 5V Regulator Output – Power Pin. Provides a regulated 5V for internal 5V circuits. It can also power

an external light sensor and/or SM Buss chip (limited to 1mA). Must be decoupled closely to the GND with a

ceramic capacitor typical value of 4.7μF.

DSEL1

3

Dimming Mode Select Input 1. Three level input. Refer to Table 1 in the applications section for functionality

DSEL2

4

Dimming Mode Select Input 2. – Two Level Logic Input. Refer to Table 1 in the applications section for

functionality

DI

5

Dimming Input – Signal Pin. Connect a DC dimming voltage or the light sensor output to this pin.

OT

6

LED Ambient Over Temperature Protection – Signal Pin – Connect to an external NTC thermistor to monitor

the LED light bar temperature. If NTC is not used, then tie this pin to the IC’s VLDO pin. The NTC needs to

be 100kΩ at 25°C and B constant of 4000. Please see the applications section for more details regarding the

OT option.

PWM

7

Pulse Width Modulated Dimming Signal – Signal Input. PWM input used for multi-dimming mode. With

DSEL1 pin tied low, a PWM signal input in the range of 100Hz to 25kHz provides direct digital dimming for the

LED outputs. With DSEL1 pin open and DSEL2 pin tied high, this pin is used as a sync input for

synchronizing the LX1996’s internal PWM dimming clock with an external clock signal of 400ns or greater

width.

RT

8

Current source setting resistor. Must be 100K

Ω between this pin and ground when Analog to Digital Dimming

or Ultrasonic Pulse Skipping modes are used. If neither mode is used, this pin may be left open or tied to

CT

9

Internal Digital Dimming frequency setting capacitor. A capacitor between this pin and ground sets the

This pin should be left open or grounded when the internal oscillator is not used.

CLF

10

PLL Loop filter connection pin. A loop filter capacitor should be connected between this pin and ground when

the internal dimming is used with synchronization mode engaged. Typical capacitor values are; 0.1uF for

200Hz; 1nF for 20Khz. This pin should be left open or grounded when the synchronization option is not used.

PRG

11

LED current programming. Connect a resistor between this pin and ground to set the LED current. Refer to

applications section for functionality

GND

12

Signal ground. Should be tied at a single common point to Power Ground (PGND pin 20).

CS1-6

13

to18

Current Sink pins – controls individual LED string current. CS pins can be wired in parallel for higher currents.

The lowest CS voltage is kept at approx. 0.8V at 20mA.