AL8843Q AUTOMOTIVE COMPLIANT 40V 3A STEP-DOWN LED DRIVER Description Pin Assignments The AL8843Q is a hysteresis mode DC-DC step-down converter, (Top View) designed for driving single or multiple series connected LEDs efficiently from a voltage source higher than the LED voltage. The device can operate from an input supply between 4.5V and 40V and SW GND 1 8 provide an externally adjustable output current up to 3A. Depending SW GND 2 7 upon supply voltage and external components, this converter can EP provide up to 60W of output power. VIN SET 3 6 The AL8843Q integrates the power switch and a high-side output NC 5 CTRL 4 current sensing circuit, which uses an external resistor to set the nominal average output current. SO-8EP Dimming can be realized by applying an external control signal to the CTRL pin. The CTRL pin will accept either a DC voltage signal or a PWM signal. Applications The soft-start time can be adjusted by an external capacitor from the CTRL pin to Ground. Applying a voltage of 0.3V or lower to the CTRL Automotive Daytime Running Lights pin will shut down the power switch. Automotive Front and Rear Fog Lights Automotive Turn/Stop Lights The AL8843Q is available in the thermally enhanced SO-8EP package Automotive Dimmable Interior Lights and automotive compliant, qualified to AEC-Q100 Grade 1, supports PPAP documentations. Features Qualified to AEC-Q100 Grade 1 Wide Input Voltage Range: 4.5V to 40V Output Current up to 3A Internal 40V NDMOS Switch Typical 4% Output Current Accuracy Single Pin for On/Off and Brightness Control by DC Voltage or PWM Signal Recommended Analog Dimming Range: 10% to 100% Soft-Start High Efficiency (Up to 97%) LED Short Protection Inherent Open-Circuit LED Protection Over Temperature Protection (OTP) Up to 1MHz Switching Frequency SO-8EP Package Available in Green Molding Compound (No Br, Sb) Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. Green Device (Note 3) The AL8843Q suitable for automotive applications requiring specific change control this part is AEC-Q100 qualified, PPAP capable, and manufactured in IATF 16949 certified facilities. AL8843Q Typical Applications Circuit V : 4.5V to 40V R IN SET VIN SET C1 CTRL D1 AL8843Q GND SW L1 Pin Descriptions Pin Number Pin Name Function 1, 2 GND Ground of IC Set Nominal Output Current Pin. Connect resistor R from this pin to VIN pin to define nominal SET 3 SET average output current. 4 NC No Connection Multi-Function On/Off and brightness control pin: Leave floating for normal operation. Drive to voltage below 0.3V to turn off output current. Drive with DC voltage (0.4V < V < 2.5V) to adjust output current from 10% to 100% of CTRL I OUT NOM. 5 CTRL Drive with an analog voltage > 2.6V output current will be 100% of I OUT NOM. A PWM signal (Low level voltage < 0.3V, High level voltage > 2.6V, transition time less than 1s) allows the output current to be adjusted over a wide range up to 100%. Connect a capacitor from this pin to ground to increase soft-start time. (Default soft-start time = 0.1ms. Additional soft-start time is approximate 1.5ms/1nF). Input Voltage (4.5V to 40V). Decouple to ground with 10F or higher X7R ceramic capacitor close to 6 VIN device. 7, 8 SW Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin to reduce EMI. Exposed pad/TAB. Connect to GND and thermal mass for enhanced thermal impedance. EP EP 2 of 18 October 2019 AL8843Q Diodes Incorporated www.diodes.com Document number: DS41943 Rev. 2 - 2