MC144898 is a LED display driver produced by Motorola
The MC14489B LED driver directly interfaces to individual lamps, 7‑segment displays, or combinations thereof. It drives LEDs with common cathodes in a multiplexed‑by‑5 fashion and communicates with a microcontroller via a synchronous serial port compatible with Motorola SPI and National Microwire. The device includes on‑chip decode and scan circuitry, data retention, and a single‑resistor current‑setting scheme.
Key features include low‑resistance FET switches for common‑cathode interfacing, a low‑power mode that extinguishes LEDs, brightness control via the serial port, and special circuitry that minimizes EMI. The driver can handle up to 25 lamps or a 5‑digit display with decimals, and supports cascading of multiple devices for larger displays.
| Operating Voltage Range of Drive Circuitry | 4.5 to 5.5 V |
|---|---|
| Operating Junction Temperature Range | -40°C to 130°C |
| Maximum Anode Driver Output Current | 35 mA |
A single device can drive up to 25 lamps, a 5‑digit display with decimals, a 4½‑digit display with sign, or a 5½‑digit configuration using a special technique.
The peak segment drive current is set by an external resistor (Rx) connected between pin 8 and ground.