SN74HC161D

The SN74HC161D is a 4-bit presettable Synchronous Binary Counter features 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 are normally associated with synchronous (ripple-clock) counters. A buffered clock input triggers the four flip-flops on the rising (positive-going) edge of the clock waveform. It is fully programmable, that is, it can be preset to any number between 0 and 9 or 15. As presetting is synchronous, 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.

• Outputs can drive up to 10 LSTTL loads
• Internal look-ahead for fast counting
• Carry output for n-bit cascading
• Synchronous counting
• Synchronously programmable
• 80µA Maximum low power consumption
• 14ns Typical tpd
• ±4mA Output drive at 5V
• 1µA Maximum low input current
• Green product and no Sb/Br