Wide Operating Voltage Range of 2 V to 6 V
Outputs Can Drive Up To 10 LSTTL Loads
Low Power Consumption, 80-μA Max ICC
Typical tpd = 20 ns
±4-mA Output Drive at 5 V
Low Input Current of 1 μA Max
Look-Ahead Circuitry Enhances Cascaded
Counters
Fully Synchronous in Count Modes
Parallel Asynchronous Load for Modulo-N
Count Lengths
Asynchronous Clear

description/ordering information
The ’HC193 devices are 4-bit synchronous, reversible, up/down binary counters.
Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change
coincidentally 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) input (UP
or DOWN). The direction of counting 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 load (LOAD) input and entering the desired data at the data inputs. The output changes to agree with the
data inputs independently of the count pulses. This feature allows the counters to be used as modulo-N dividers
simply by modifying the count length with the preset inputs.
A clear (CLR) input has been provided that forces all outputs to the low level when a high level is applied. 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 (BO) output
produces a low-level pulse while the count is zero (all outputs low) and DOWN is low. Similarly, the carry (CO)
output produces a low-level pulse while the count is maximum (9 or 15), and UP is low. The counters then can
be cascaded easily by feeding BO and CO to DOWN and UP, respectively, of the succeeding counter.