What this LED driver does in a signage assembly
The MAX6978AUE+ is a linear LED driver from Analog Devices / Maxim Integrated designed for signage applications. It integrates eight constant-current outputs each rated for 55 mA, controlled through a shift register interface. The shift register topology allows daisy-chaining multiple MAX6978AUE+ devices for larger display arrays, with the serial data passing through each IC.
Each of the eight outputs sinks 55 mA, which is enough for standard through-hole or high-brightness SMD LEDs used in signage. The 5.5 V maximum output voltage and supply rail means this driver is intended for low-voltage LED strings, not series chains that drop more than a few volts. For typical red/green/blue LEDs with a forward voltage around 2 V to 3.5 V, the headroom is adequate at 5 V supply.
The 16-TSSOP with exposed pad (0.173" body width, 4.40 mm) is a surface-mount package that reworks reasonably well with hot air if you preheat the board. For production quantities the MAX6978AUE+ is also available in tape-and-reel as the MAX6978AUE+T variant — same silicon, different shipping medium.