A8512: LED Backlight Driver for LCD Monitors and Televisions

Description

This device is in production, however, it has been deemed Pre-End of Life. The product is approaching end of life. Within a minimum of 6 months, the device will enter its final, Last Time Buy, order phase. Date of status change: December 5, 2018.

Recommended Substitutions: ALT80600.

The A8512 is a multi-output WLED/RGB driver for backlighting LCD monitors and televisions. It integrates a boost controller to drive external MOSFET, and six internal current-sinks. The boost converter operates in constant frequency (programmable) current mode control.

PWM dimming allows LED currents to be controlled in 500:1 ratio. The LED sink current is set by an external R_ISET resistor (see chart at right). More than one LED sinks can be combined together to achieve even higher current per LED string. Multiple A8512s can be connected in parallel, with one master controller controlling the boost stage, and up to five slave controllers, which act as LED sinks. This allows up to 36 LED strings to be powered by just one boost converter.

The A8512 operates from a single supply of 8 to 24 V. It provides protection against overvoltage, open or shorted LED string, and overtemperature. A dual level cycle-by-cycle current limit function provides soft start and protects against overloads.

The device is provided in a 24-pin SOICW package (LB), with internally fused pins for enhanced thermal dissipation, and a 28-contact 5 mm × 5 mm QFN package (ET) and a 24-pin TSSOP package (LP), both with an exposed thermal pad for enhanced thermal dissipation. All packages are lead (Pb) free, with 100% matte tin leadframe plating.

Top Features

  • Six integrated high current sinks
  • Fixed frequency current mode control with integrated gate driver
  • 300 kHz to 1 MHz adjustable switching frequency
  • Controlled startup using options of Enable, PWM signal, or battery voltage ramp
  • Parallel operation with one boost controller (master) and up to five slave controllers
  • Active current sharing between LED strings for ±0.6% accuracy and matching
  • No audible MLCC noise during PWM dimming
  • Adjustable overvoltage protection (OVP)
  • Open or shorted LED string protection
  • Overtemperature, cycle-by-cycle current limit, and undervoltage protection
  • SOIC 24-pin package for easy single-side PCB manufacturing, or TSSOP 24-pin and QFN 28-contact packages with exposed thermal pad for better thermal performance

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A8512EETTR-T 28-lead QFN -40°C to 85°C Yes View Data pre-EOL Contact your
local sales rep
Check
Distributor Stock
A8512ELBTR-T 24-lead SOIC -40°C to 85°C Yes View Data Discontinued Contact your
local sales rep
Check
Distributor Stock
A8512ELPTR-T 24-lead TSSOP -40°C to 85°C Yes View Data pre-EOL Contact your
local sales rep
Check
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.

Packaging

The device is provided in a 24-pin SOICW package (LB), with internally fused pins for enhanced thermal dissipation, and a 28-contact 5 mm × 5 mm QFN package (ET) and a 24-pin TSSOP package (LP), both with an exposed thermal pad for enhanced thermal dissipation. All packages are lead (Pb) free, with 100% matte tin leadframe plating.

LB-SOIC 24 pin ET QFN with exposed pad 28 leadLP-eTSSOP 24 lead