The SN54/74LS196 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
SN54/74LS197 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 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