SDFS031A - D3693, JANUARY 1991 - REVISED OCTOBER 1993
The SN74F193A is a synchronous, 4-bit binary up/down counter. Synchronous counting operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed by the steering logic. This mode of operation eliminates the output counting spikes normally associated with asynchronous (ripple-clock) counters.
The outputs of the four flip-flops are triggered on a low-to-high-level transition of either count/clock (UP or DOWN) input. The direction of the count is determined by which count input is pulsed while the other count input is high.
All four counters are fully programmable; that is, each output may
be preset to either level by placing a low on the 
input and entering the desired data
at the data (D) inputs. The output will change to agree with the data
inputs independently of the count pulses. This feature allows the
counters to be used as modulo-N dividers by simply modifying the
count length with the preset inputs.
A high level applied to the clear (CLR) input forces all outputs to the low level. The clear function is independent of the count and load inputs.
These counters were designed to be cascaded without the need for
external circuitry. The borrow (
) output produces a low-level pulse while the count is
zero (all Q outputs low) and the DOWN input is low. Similarily, the
carry () output
produces a low-level pulse while the count is 15 (all Q outputs high)
and the UP input is low. The counters can then be easily cascaded by
feeding the borrow and carry outputs to the count-down and count-up
inputs, respectively, of the succeeding counter.
The SN74F193A is characterized for operation from 0°C to 70°C.