4-Bit Counters/Registers

Multiplexed Outputs for Counter or Latched

Data

3-State Outputs Drive Bus Lines Directly

'LS696.. Decade Counter, Direct Clear

'LS697.. Binary Counter, Direct Clear

'LS699.. Binary Counter, Synchronous

Clear

description

These low-power Schottky LSI devices incorporate

synchronous up/down counters, four-bit D-type registers,

and quadruple two-line to one-line multiplexers with three

state outputs in a single 20-pin package. The up/down

counters are programmable from the data inputs and

feature enable P and enable T and a ripple-carry output

for easy expansion. The register/counter select input R/C,

selects the counter when low and the register when high

for the three-state outputs, QA. QB. QC, and QD. These

outputs are rated at 12 and 24 milliamperes (54LS/74LS)

for good bus driving performance.

Both the counter CCK and register clock RCK are positiveedge triggered. The counter clear CCLR is

active low and is asynchronous on the 'LS696 and

'LS697, synchronous on the 'LS699. Loading of the

counter is accomplished when LOAD is taken low and

a positive transition occurs on the counter clock CCK.

Expansion is easily accomplished by connecting RCO

of the first stage to ENT of the second stage, etc. All

ENP inputs can be tied common and used as a master

enable or disable control.