SN54190

The SN54190 is a kind of synchronous, reversible up/down counter with a complexity of 58 equivalent gates. Synchronous operation is provided with all flip-flops clocked simultaneously so that the outputs change coincidently with each other when so instructed by the steering logic. This SN54190 operation eliminates the output counting spikes normally associated with asynchronous (ripple clock) counters. The outputs of the four master-slave flip-flops are triggered on a low-to-high transition of the clock input if the enable input is low. In addition, the counter is fully programmable.

There are some features of SN54190 as follows: (1)counts 8-4-2-1 BCD; (2)single down/up count control line; (3)count enable control input; (4)ripple clock output for cascading; (5)asychronously presettable with load control; (6)parallel outputs; (7)cascadable for n-bit applications.

The following is about the absolute maximum ratings of SN54190 over operating free-air temperature range (unless otherwise noted): (1)supply voltage, VCC: 7 V; (2)input voltage: 5.5 V; (3)operating free-air temperature range: -55 to 125; (4)storage temperature range: -65 to 150. Then is about the recommended operating conditions: (1)VCC, supply voltage: 4.5 V min, 5 V typ and 5.5 V max; (2)IOH, high-level output current: -0.8 mA max; (3)IOL, low-level output current: -16 mA max; (4)fclock, input clock frequency: 0 to 20 MHz; (5)tw(clock), width of clock input pulse: 25 ns min; (6)tw(load), width of load input pulse: 35 ns min; (7)thold, data hold time: 0 ns; (8)tA, operating free-air temperature: -55 to 125.