The Texas Instruments SN74LV161AD is a 4-bit synchronous binary counter from the 74LV-A family, designed for general-purpose counting, frequency division, and timing-chain applications in digital logic systems. It counts up on each positive edge of the clock input and includes an asynchronous reset that forces all outputs low regardless of the clock state. The part operates from a 2 V to 5.5 V supply, making it compatible with both 3.3 V and 5 V logic rails — a common requirement when bridging legacy and modern digital buses. With a count rate of 95 MHz, it handles fast clocked counters in microcontroller peripheral glue, programmable logic interface, or test equipment dividers.
95 MHz count rate — what it means for timing margin
The 95 MHz count rate is the maximum clock frequency at which the counter reliably increments. In a 3.3 V system, propagation delays through the counter and any cascaded stages eat into the timing budget; at 95 MHz the clock period is about 10.5 ns, so you need to account for the counter's own propagation delay plus setup time of the next stage. For most microcontroller or FPGA interfaces running below 50 MHz, this part leaves comfortable margin. If you are cascading multiple counters for wider bit widths, the cumulative delay may limit the top speed — a single-stage 4-bit counter at 95 MHz is straightforward, but a 16-bit chain of four devices will need careful clock distribution.
Supply range and logic-level compatibility
The 2 V to 5.5 V supply range is a practical advantage: it runs from a 3.3 V rail in a mixed-voltage design without level shifters on the counter outputs, and it can also operate at 5 V for TTL-compatible legacy systems. The 74LV-A family is specified with LVCMOS input thresholds, so at 3.3 V the VIH minimum is typically 0.7 × VCC (about 2.3 V), which is easily driven by a 3.3 V microcontroller GPIO. At 5 V, the thresholds shift proportionally. This part is a clean drop-in for 3.3 V logic designs that need a synchronous counter.
It is ROHS3 compliant.