AX2021

AX2021 32V, 0.45A Step-down High Brightness LED Driver with 5000:1 Dimming  GENERAL DESCRIPTION The AX2021 is a continuous conduction mode inductive step-down converter, designed for driving single or multiple series connected LED efficiently from a voltage source higher than the total LED chain voltage. The device operates from an input supply between 8V and 32V and provides an externally adjustable output current of up to 0.45A. Depending upon the supply voltage and external components, the AX2021 can provide more than 15 watts of output power. The AX2021 includes the power switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current, and a dedicated DIM input accepts a wide range of pulsed dimming. Applying a voltage of 0.3V or lower to the DIM pin turns the output off and switches the device into a low current standby state. The AX2021 is available in TSOT-23-5L package.  FEATURES Simple low parts count Wide input voltage range: 8V to 32V VÛmw`RyÑb€ current Up to 0.45A output Single pin on/off and brightness control using PWM Up to 1MHz switching frequency Typical 5% output w.goftechm current accuracy High-Side Current Sense Hysteretic Control: No Compensation Adjustable Constant LED Current 1/11 AX2021  BLOCK DIAGRAM VIN V25 CSN CS COMPARATOR + 130mV 2.5V 70µ + GATE DRIVER Driver SW UVLO COMPARATOR GND DIM BUFFER DIM  PIN ASSIGNMENT The package of AX2021 is TSOT-23-5L; the pin assignment is...