A6261: Protected LED Array Driver - ALLEGRO MICROSYSTEMS - #1

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Description The A6261 is a linear, programmable current regulator providing up to 100 mA from each of four outputs to drive arrays of high brightness LEDs. The regulated LED current from each output, accurate to 5%, is set by a single reference resistor. Current matching in each string is better than 10% without the use of ballast resistors. Driving LEDs with constant current ensures safe operation with maximum possible light output. Output control is provided by an enable input, giving direct control for PWM applications. Outputs can be connected in parallel or left unused as required. Short detection is provided to protect the LEDs and the A6261 during a short-to-ground at any LED output pin. An open LED in any of the strings disables all outputs, but can be overridden. Shorted LED output pins or open LEDs are indicated by a fault flag. A temperature monitor is included to reduce the LED drive current if the chip temperature exceeds a thermal threshold. The device packages are a 10-pin MSOP (LY) and a 16-pin TSSOP (LP), both with exposed pad for enhanced thermal dissipation. They are lead (Pb) free, with 100% matte tin leadframe plating. A6261A-DS, Rev. 3 Features and Benefits Total LED drive current up to 400 mA Current shared equally up to 100 mA by up to 4 strings 6 to 50 V supply Low dropout voltage LED output short-to-ground and thermal protection Disable on open LED detection option Enable input for PWM control Current slew rate limit during PWM Current set by reference resistor Automotive K-temperature range version (–40°C to 150°C) Packages Typical Application Diagram Not to scale A6261 Protected LED Array Driver A6261 + – LA1 VIN PWM dimming input Power input GND LA2 LA3 LA4 EN FF IREF THTH 10-pin MSOP with exposed thermal pad (suffix LY) 16-pin TSSOP with exposed thermal pad (suffix LP)