1

FEATURES

1

2

3

4

8

7

6

5

DRJ (QFN) PACKAGE

(TOP VIEW)

I

NC

Q

D

PWM

ST

GND

REF

NC – No internal connection

DESCRIPTION/ORDERING INFORMATION

TL4242

ADJUSTABLE LED DRIVER

• Adjustable Constant Current

up to 500 mA (±5%)

• Wide Input Voltage Range up to 42 V

• Low Drop Voltage

• Open-Load Detection

• Overtemperature Protection

• Short-Circuit Proof

• Reverse-Polarity Proof

• Wide Temperature Range: –40°C to 150°C

The TL4242 is an integrated adjustable constant-current source, driving loads up to 500 mA. The output current

level can be adjusted via an external resistor. The device is designed to supply high-power LEDs (for example,

OSRAM Dragon LA W57B) under the severe conditions of automotive applications, resulting in constant

brightness and extended LED lifetime. It is provided in the DRJ (QFN) package. Protection circuits prevent

damage to the device in case of overload, short circuit, reverse polarity, and overheat. The connected LEDs are

protected against reverse polarity as well as excess voltages up to 45 V.

The integrated PWM input of the TL4242 permits LED brightness regulation by pulse-width modulation (PWM).

Due to the high input impedance of the PWM input, the LED driver can be operated as a protected high-side

switch.

The TL4242 is characterized for operation from –40

°C to 150°C.

An external shunt resistor in the ground path of the connected LEDs is used to sense the LED current. A

regulation loop holds the voltage drop at the shunt resistor at a constant level of 177 mV (typ). The

current using the equation:

The output current is shown as a function of the reference resistance in Figure 1. With the PWM input, the LED

brightness can be regulated via duty cycle. Also, PWM = L sets the TL4242 in sleep mode, resulting in a very

low current consumption of <1

µA (typ). Due to the high impedance of the PWM input (see Figure 4), the PWM

pin also can be used as an enable input.

ORDERABLE PART NUMBER

TOP-SIDE MARKING

–40

°C to 150°C

QFN – DRJ

Reel of 1000

TL4242DRJR

T4242

(1)

For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI

web site at www.ti.com.

(2)

Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Copyright © 2008, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.