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High-Performance Power ICs and Hall-Effect Sensors
Serial-Input Latched LED Drivers with Programmable Constant-Current
Outputs
June 8, 1999, Allegro MicroSystems, Inc. announces the release of a new family of 8-bit and 16-bit programmable, constant-current LED drivers with sink outputs. The A6275 and A6276, which feature 8 and 16-bit outputs respectively, are designed specifically for LED driving applications and feature CMOS shift registers, accompanying data latches, and npn outputs rated at 17 V.
The serial-input, CMOS shift registers and latches allow for direct interfacing with microprocessor-based systems. With a 5 V logic supply, typical serial data input rates are up to 20 MHz. A serial data output permits cascaded connections in applications requiring additional drivelines. The devices can be configured in multiplexed configurations with an accompanying source driver.
The output current is programmable up to 90 mA with a single external resistor and output to output current is matched to 1.5% typical. For applications requiring inter-digit blanking, all the outputs can be turned off simultaneously with the device's OUTPUT ENABLE input high. The OUTPUT ENABLE can also be used to operate the outputs at a selected duty cycle to control LED illumination.
Two temperature ranges are available for use in applications from commercial to industrial enabling operation over the temperature range of -40°C to +85°C. Package options include a through hole DIP and surface mount SOIC. Copper lead frames and low logic-power dissipation allow these devices to be used in most LED display applications including seven segment, bar graph and dot matrix configurations. In addition, with 90 mA output current capability and low thermal impedance, the devices are ideal for large sign applications.
Headquartered in Worcester, Massachusetts, Allegro MicroSystems serves the automotive, industrial, and computer peripheral markets with its growing line of mixed-signal (analog/digital) products. Allegro specializes in developing system-level solutions that integrate proprietary combinations of bipolar, CMOS and DMOS structures in a single monolithic integrated circuit.
Allegro's web site is located at www.allegromicro.com and includes datasheets on the 6275 and 6276.