75190

PRESETTABLE BCD/DECADE UP/DOWN COUNTERS PRESETTABLE 4-BIT BINARY UP/DOWN COUNTERS The SN54 / 74LS190 is a synchronous UP/ DOWN BCD Decade (8421) Counter and the SN54/ 74LS191 is a synchronous UP / DOWN Modulo-16 Binary Counter. State changes of the counters are synchronous with the LOW-to-HIGH transition of the Clock Pulse input. An asynchronous Parallel Load (PL) input overrides counting and loads the data present on the Pn inputs into the flip-flops, which makes it possible to use the circuits as programmable counters. A Count Enable (CE) input serves as the carry / borrow input in multi-stage counters. An Up / Down Count Control (U/D) input determines whether a circuit counts up or down. A Terminal Count (TC) output and a Ripple Clock (RC) output provide overflow/underflow indication and make possible a variety of methods for generating carry / borrow signals in multistage counter applications. Low Power . . . 90 mW Typical Dissipation High Speed . . . 25 MHz Typical Count Frequency Synchronous Counting Asynchronous Parallel Load Individual Preset Inputs Count Enable and Up/ Down Control Inputs Cascadable Input Clamp Diodes Limit High Speed Termination Effects CONNECTION DIAGRAM DIP (TOP VIEW) VCC 16 P0 15 CP 14 RC 13 TC 12 PL 11 P2 10 P3 9 NOTE: The Flatpak version has the same pinouts (Connection Diagram) as the Dual In-Line Package. 1 P1 2 Q1 3 Q0 4 CE 5 U/D 6 Q2 7 Q3 8 GND PIN NAMES LOADING (Note a) HIGH LOW CE Count Enable (Activ...