The CD54AC161 and CD74AC161 devices are 4-bit binary counters. These synchronous, presettable counters feature an internal carry look-ahead for application in high-speed counting designs. 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 count-enable (ENP, ENT) inputs and internal gating. This mode of operation eliminates the output counting spikes that normally are associated with synchronous (ripple-clock) counters. A buffered clock (CLK) input triggers the four flip-flops on the rising (positive-going) edge of the clock waveform. These devices are fully programmable; that is, they can be preset to any number between 0 and 9 or 15. Presetting is synchronous; therefore, setting up a low level at the load input disables the counter and causes the outputs to agree with the setup data after the next clock pulse, regardless of the levels of the enable inputs. The clear function is
The CD54AC161 and CD74AC161 are 4-bit binary counters designed with synchronous operation and an internal carry look-ahead circuit. This architecture allows for cascading multiple counters to create n-bit systems without additional external gating, ensuring all flip-flops change state simultaneously on the clock edge.
These devices feature fully programmable presetting capabilities, allowing initialization to any number between 0 and 15 (or 9), as well as an asynchronous clear function. The CD54AC161 is rated for military temperature ranges (-55°C to 125°C), while the CD74AC161 operates in commercial temperatures (-40°C to 85°C).
| Operating Temperature (CD54AC161) | -55°C to 125°C |
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Yes, the devices are fully programmable and can be preset to any number between 0 and 15.
The device requires a minimum clock frequency of 6 MHz when operating at 3.3 V.