Description

The A6278 and A6279 devices are specifically designed for LED display applications. Each of these BiCMOS devices includes a CMOS shift register, accompanying data latches, and NPN constant-current sink drivers. The A6278 contains 8 sink drivers, while there are 16 in the A6279.

The CMOS shift register and latches allow direct interfacing with microprocessor-based systems. With a 3.3 or 5 V logic supply, typical serial data-input rates can reach up to 25 MHz. The LED drive current is determined by the user’s selection of a single resistor. A CMOS serial data output permits cascading between multiple devices in applications requiring additional drive lines. Open LED connections can be detected and signaled back to the host microprocessor through the SERIAL DATA OUT pin.

Features and Benefits

▪ 3.0 to 5.5 V logic supply range

▪ Schmitt trigger inputs for improved noise immunity

▪ Power-On Reset (POR)

▪ Up to 90 mA constant-current sinking outputs

▪ LED open circuit detection

▪ Low-power CMOS logic and latches

▪ High data input rate

▪ 20 ns typical staggering delay on the outputs

▪ Internal UVLO and thermal shutdown (TSD) circuitry