Constant current, latched LED drivers

CMOS shift register and latches allow the devices to be directly interfaced with microprocessor-based systems. Using 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 user selection of a single resistor and a CMOS serial data output permits cascading between multiple devices in applications requiring additional drive lines.

Open LED connections can be detected and signalled back to the host microprocessor through the serial data out pin. The devices also feature an output delay feature which improves ground current spikes, Schmitt trigger inputs for improved noise immunity and Internal UVLO and thermal shut down (TSD) circuitry.

Three package styles are available from stock: a DIP (type A) for through-hole applications, and for surface-mount, an SOIC (type LW) and a TSSOP with exposed thermal pad (type LP). All package styles for the A6278 are electrically identical to each other, as are the A6279. The A6278 contains 8 sink drivers, while there are 16 in the A6279. All packages are lead free and RoHS compliant, with tin plated leadframes.