74LS192 TTL BCD Counters Up / Down for Decade Dual Clock
Integrated Circuit TTL 74LS192, 4-bit synchronous up / down BCD counters (dual clock having the complexity of 55 equivalent gates. Synchronous operation is provided by having all flip flops synchronized simultaneously so that the outputs change coincident with each other when they are Instructed by address logic. This mode of operation eliminates the output count spikes normally associated with asynchronous counters (ripple clock).
The outputs of the four master slave change failures are caused by a low to high transition of any count (clock) input The counting direction is determined by which counting input is pressed while the other counting input is high.
This counter is fully programmable; that is, each output can be preset to any of the levels by entering the desired data from the data inputs while the load input is low. The output will change to match the data inputs regardless of the counting pulses. This feature allows the counter to be used as a divisor N module simply by modifying the count length with the preset inputs.
A clear 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. The clear, count and load inputs are damped to lower driving requirements. This reduces the number of clock drivers, etc., required for long words.
This device was designed to be cascaded without the need for external circuits. Both borrow and carry outputs are available to cascade both the counting and down counting functions. The row output produces a pulse equal to the width of the rising input count when an overflow condition exists.
The counter can easily be cascaded by powering the loan and taking outputs to the count down and counting the inputs, respectively, of the next counter.
Individual preset for each flip-flop
Minimum supply voltage: 4.25 V
Maximum supply voltage: 5.25 V
Dissipation: 95 mW
Current: 8 mA
Minimum operating temperature: 0C
Maximum operating temperature: 70C