The SN74LS688N is an 8-bit synchronous up/down binary presettable counter from Texas Instruments. It is a part of the popular 74-series of TTL logic ICs. The SN74LS688N features full ripple-carry output, which makes it suitable for synchronous applications. Its 8-bit output can be preset to either high or low logic levels. Its power supply operating range is 4.5 to 5.5V, with a 5V supply recommended for reliable operation. This chip is typically commonly used as counters, dividers, and shift registers, as well as in circuits related to sequencing and timing.