Package of 5!

New old stock (NOS), unused, genuine part: National DM74193N / DM8563N Synchronous Up/Down 4-Bit Binary Counter with Dual Clock, PDIP-14.

Manufacturer: National Semiconductor
Manufacturer Part Number: DM74193N / DM8563N
74 Series Part: 74193
Product Category: Counter ICs, Binary
Counter Type: Binary
Number of Bits: 4
Counting Method: Synchronous
Counting Sequence: Up/Down
Supply Voltage - Min: 4.5 V
Supply Voltage - Max: 5.5 V
Package / Case: PDIP-14, Plastic
RoHS: NO
Packaging: Anti-Static

Features
■ Fully independent clear input
■ Synchronous operation
■ Cascading circuitry provided internally
■ Individual preset each flip-flop

General Description
This circuit is a synchronous up/down 4-bit binary counter. Synchronous operation is provided by having all flip-flops clocked simultaneously, so that the outputs change together 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 master-slave flip-flops are triggered by a low-to-high level transition of either count (clock) input. The direction of counting is determined by which count input is pulsed, while the other count input is held high. This counter is fully programmable; that is, each output may be preset to either level by entering the desired data at the inputs while the load input is low. The output will change independently of the count pulses. This feature allows the counter to be used as modulo-N divider by simply modifying the count length with the preset inputs. A clear input has been provided which, when taken to a high level, forces all outputs to the low level; independent of the count and load inputs. The clear, count, and load inputs are buffered to lower the drive requirements of clock drivers, etc., required for long words. This counter was designed to be cascaded without the need for external circuitry. Both borrow and carry outputs are available to cascade both the up and down counting functions. The borrow output produces a pulse equal in width to the count down input when the counter underflows. Similarly, the carry output produces a pulse equal in width to the count up input when an overflow condition exists. The counter 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.