74LS197

The 74LS197 decade counter is partitioned into divide-by-two and divide-by-five sections which can be combined to count either in BCD (8, 4, 2, 1) sequence or in a bi-quinary mode producing a 50% duty cycle output. The 74LS197 contains divide-by-two and divide-by-eight sections which can be combined to form a modulo-16 binary counter. Low Power Schottky technology is used to achieve typical count rates of 70 MHz and power dissipation of only 80 mW.

Both circuit types of the 74LS197 have a Master Reset (MR) input which overrides all other inputs and asynchronously forces all outputs LOW. A Parallel Load input (PL) overrides clocked operations and asynchronously loads the data on the Parallel Data inputs (Pn) into the flip-flops. This preset feature makes the circuits usable as programmable counters. The circuits can also be used as 4-bit latches, loading data from the Parallel Data inputs when PL is LOW and storing the data when PL is HIGH.
• Low Power Consumption - Typically 80 mW
• High Counting Rates - Typically 70 MHz
• Choice of Counting Modes - BCD, Bi-Quinary, Binary
• Asynchronous Presettable
• Asynchronous Master Reset
• Easy Multistage Cascading
• Input Clamp Diodes Limit High Speed Termination Effects