Datasheet

NTE74LS192
Integrated Circuit
TTL − Synchronous 4−Bit Up/Down Counter
Description:
The NTE74LS192 is a synchronous BCD reversible up/down counter in a 16−Lead plastic DIP type
package having the complexity of 55 equivalent gates. Synchronous 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 master−slave flip−flops are triggered by a low−to−high transition of either count
(clock) input. The direction of counting is determined by which count input is pulsed while the other
count input is high.
This counter is fully programmable; that is, each output may be preset to either level by entering the
desired data of the data inputs while the load input is low. The output will change to agree with the
data inputs independently of the count pulses. This feature allows the counter to be used as a mod-
ulo−N divider by simply modifying the count length with the preset inputs.
A clear input has been provided which 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
buffered to lower the drive 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 circuitry. Both borrow and
carry outputs are available to cascade both the up−counting and down−counting functions. The bor-
row 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.
Features:
D Cascading Circuitry Provided Internally
D Synchronous Operation
D Individual Preset to Each Flip−Flop
D Fully Independent Clear Input
Absolute Maximum Ratings:
(Note 1)
Supply Voltage, V
CC
7V.................................................................
DC Input Voltage, V
IN
7V................................................................
Power Dissipation, P
D
95mW............................................................
Operating Temperature Range, T
A
0C to +70C............................................
Storage Temperature Range, T
stg
−65C to +150C........................................
Note 1. Unless otherwise specified, all voltages are referenced to GND.