74HC161

The 74HC161 is a high-speed, 4-bit presettable synchronous binary counter IC. It counts from 0 to 15 (binary 0000 to 1111) on the positive edge of a clock signal and features an asynchronous Master Reset (clear) to instantly zero the outputs. [1, 2, 3, 4, 5]
Key Specifications & Features
• Logic Type: 4-bit synchronous binary counter
• Operating Voltage: 2V to 6V
• Clock Frequency: Up to ~ 95MHz (depends on supply voltage and manufacturer)
• Reset Type: Asynchronous
• Cascadable: Built-in look-ahead carry logic allows you to easily chain multiple ICs together for larger counts (e.g., 8-bit, 12-bit, etc.) [1, 2, 3, 4, 5, 6]
How It Works (Core Pins)
• Clock (CP): Counts advance on the positive-going edge of the clock pulse.
• Master Reset (MR): When held LOW, it asynchronously resets all outputs (Q₀ – Q₃) to 0, regardless of other inputs.
• Parallel Enable (PE): When pulled LOW, it overrides the counter and forces the binary data on inputs D₀ – D₃ to be loaded directly into the counter on the next clock pulse.
• Count Enable (CEP & CET): Both inputs must be HIGH for the counter to increment. [1]
Typical Use Cases
• Digital timers and clocks
• Frequency divider circuits
• Programmable digital counters
• Microcontroller-based event counting and control logic [1]

Package Options: Available through-hole (DIP-16) or surface-mount (SOIC-16, TSSOP-16)