SN74HCS86: Max input frequency

dBrock

Part Number: SN74HCS86
Other Parts Discussed in Thread: SN74LVC1G58

Hi,

I am looking into designing a frequency doubling circuit using the SN74HCS86 (XOR) and a comparator. The input freq is ~50 MHz, so the doubled output is ~100 MHz.

Do you know what the max input frequency is for the SN74HCS86? Is there a better suited part for this frequency input?

Also, do you have a better recommendation for a frequency doubler using logic (avoiding PLL for power reasons)? Thanks!

Best,

Dan

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 276380 points

The bottleneck is the output switching speed. For a 50 pF load, it's 9 MHz at 2 V, 22.5 MHz at 4.5 V, and 32.5 MHz at 6 V.

The SN74LVC1G58 would be faster (87.5 MHz at 3.3 V, 100 MHz at 5 V).

A simple RC circuit might suffice:

Logic

Logic forum

SN74HCS86: Max input frequency