A8501中文资料2兆赫， 4 Channel100毫安WLED / RGB驱动器数据手册Allegro规格书

描述 Description

These parts are in production but have been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available. Date of status change: December 5, 2018

Recommended Substitutions: ALT80600.

The A8501 is a multioutput WLED/RGB driver for backlighting medium-size displays. The A8501 integrates a boost converter and four 100 mA current sinks. LED channels can be tied together for up to 400 mA sink capability. It can work from a single power supply of 8 to 21 V and withstand up to 40 V. The boost converter is a constant frequency, current-mode converter.

Operating frequency can be set to 2 MHz in order to avoid interference with the AM radio band. The integrated boost DMOS switch is rated for 40 V at 3.6 A. PWM dimming allows LED currents to be controlled at up to a 1000:1 ratio. Additional 4:1 dimming can be achieved by using the DIM pin.

The A8501 provides protection against output connector shorts through an integrated output disconnect switch. An optional external thermistor can be used to limit LED current based on panel temperature.

The device is supplied in a surface mount, 28-pin TSSOP package (suffix LP), with exposed thermal pad for enhanced thermal dissipation. It is lead (Pb) free, with a leadframe plating choice of 100% matte-tin (suffix T) or tin-bismuth (suffix B).

特性 Features

• 600 kHz to 2.2 MHz switching frequency—ability to operate above the AM band
• Internal bias supply for single-supply operation (VIN = 8 to 21 V)
• Boost converter with integrated 40 V DMOS switch and OVP—load-dump protection
• 3.5 µA shutdown current—limits battery drain
• Active current sharing between LED strings for 0.8% current matching and 0.7% accuracy
• Drive up to 9 series LEDs in 4 parallel strings, 36 LEDs maximum (Vf = 3.5 V, If = 100 mA)
• LED sinks rated for 100 mA each (400 mA total)
• PWM dimming with LED PWM duty cycle control
• 4000:1 dimming range
• Extensive fault mode protection schemes:

• Shorted LED protection against misconnected loads— with true output disconnect
• Open LED disconnect protects against LED failures
• External thermistor sensing to limit LED temperature
• Output overvoltage protection (OVP): 19.5 V default can be adjusted as high as 38 V
• Open Schottky and open OVP resistor protection against external component failure
• Input under- and overvoltage protection (UVLO and OVLO) against VIN variation
• Boost current limit, output short circuit limit, overtemperature protection (OTP), and soft start

简介

A8501属于集成电路（IC）的LED驱动器。由制造生产的A8501LED 驱动器器件属于 LED 驱动器电源管理集成电路 (PMIC) 系列，可通过标称固定电压的电源为负载（通常为发光二极管）提供电流，并且电流可控。它与用于电压调节的类似产品的主要区别在于，这类器件提供较低的反馈电压（以提高系统能效），而且通常可对器件工作点进行外部控制，可在照明应用中用于实现调光功能。