SN74LV393ANSR
双4位二进制计数器 DUAL 4-BIT BINARY COUNTERS
The LV393A devices contain eight flip-flops and additional gating to implement two individual 4-bit counters in a single package. These devices are designed for 2-V to 5.5-V VCC operation.
These devices comprise two independent 4-bit binary counters, each having a clear CLR and a clock CLK\ input. These devices change state on the negative-going transition of the CLK\ pulse. N-bit binary counters can be implemented with each package, providing the capability of divide by 256. The LV393A devices have parallel outputs from each counter stage so that any submultiple of the input count frequency is available for system timing signals.
These devices are fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the devices when they are powered down.