AL8862Q AUTOMOTIVE GRADE 55V 1A STEP-DOWN CONVERTER Description Pin Assignments (Top View) The AL8862Q is a step-down DC/DC converter designed to drive LEDs with a constant current. The AL8862Q operates with an input supply voltage from 5V to 55V and provides an externally adjustable CTRL SET 1 8 output current up to 1A. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating GND GND 2 7 EP the need for ballast resistors. The AL8862Q switches at frequency up FAULT 3 6 SW to 1MHz. This allows the use of smaller size external components, hence minimizing the PCB size. VIN 4 5 SW The AL8862Q integrates the power switch and a high-side output SO-8EP current sensing circuit. Maximum output current of AL8862Q is set via an external resistor connected between the VIN and SET input Applications pins. Dimming is achieved by applying either a DC voltage or a PWM signal at the CTRL input pin. The soft-start time can be adjusted Automotive Interior LED Lamps using an external capacitor from the CTRL pin to the ground. An Automotive Exterior LED Lamps input voltage of 0.3V or lower at CTRL pin will shut down the power switch. The AL8862Q is qualified to AEC-Q100 Grade 1 and is automotive grade to support PPAPs. Features Wide Input Voltage Range: 5V to 55V Output Current up to 1A Internal 55V NDMOS Switch Typical 4% Output Current Accuracy Single Pin for On/Off and Brightness Control by DC Voltage or PWM Signal High Efficiency (Up to 97%) Fault Status Indication for Abnormal Operation LED Short-Circuit Protection Inherent Open-Circuit LED Protection Current-Sense Resistor Short-Circuit Protection Over Temperature Shutdown Up to 1MHz Switching Frequency SO-8EP Packages 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 AL8862Q is suitable for automotive applications requiring specific change control this part is AEC-Q100 qualified, PPAP capable, and manufactured in IATF 16949 certified facilities. AL8862Q Typical Applications Circuit R V : 5 to 55V SET IN VIN SET CTRL C1 AL8862Q D1 FAULT GND SW L1 Pin Descriptions Pin Number Pin Name Function Set Nominal Output Current Pin. Connect resistor R from this pin to VIN to define nominal average SET 1 SET output current. 2,7 GND Ground of IC 3 FAULT FAULT Indication. Asserted Low to report faulty conditions. Needs an external pull-up resistor. Input voltage (5V to 55V). Decouple to ground with 10F or higher X7R ceramic capacitor close to 4 VIN device. 5,6 SW Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin to reduce EMI. 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 I SET OUT NOM 8 CTRL Drive with an analog voltage >2.6V output current will be 100% of IOUT NOM A PWM signal (Low level <0.3V, High level >2.6V, transition times 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 approximately 1.5ms/1nF) EP EP Exposed pad/TAB connects to GND and thermal mass for enhanced thermal impedance. Functional Block Diagram SET FAULT SW 1 3 5, 6 4 OTP VIN SW Open Fault Current VDD Generator I LIMITER Logic Monitor OCP Comp Ref Hysteresis BG & Logic Driver PWM Control Reference 8 OTP PWM/DC OTP CTRL Dimming PWM 2 7 GND GND 2 of 16 December 2019 AL8862Q Diodes Incorporated www.diodes.com Document number: DS42199 Rev. 3 - 2