Dual 4-bit synchronous binary counter for industrial counting
The Nexperia 74HC4520DB,112 is a dual 4-bit synchronous binary counter from the 74HC family, built to handle up/down counting in industrial and automotive-temperature environments. Each of the two elements counts four bits synchronously on the positive or negative clock edge, with an asynchronous reset per counter.
69 MHz count rate and dual-edge triggering
The 69 MHz count rate is the headline speed spec — it tells you the maximum clock frequency the counter can accept while maintaining proper synchronous operation. If your incoming pulse train exceeds 69 MHz, this part will miss counts. The dual-edge trigger (positive or negative) gives flexibility: you can clock from a rising-edge sensor output or a falling-edge signal without external inversion. The asynchronous reset (active-high on each counter) lets you clear both counters independently without waiting for a clock edge, which simplifies power-on or fault-recovery sequencing.
For dual-sourcing resilience, the 74HC4520 function is a standard 74HC logic function available from multiple vendors (Nexperia, TI, Toshiba, etc.) in the same SSOP-16 footprint, though pin-compatibility should be verified against the specific vendor datasheet.