The 74XX160/74XX162 is the decade divider that runs at maximum clock rate for the chip. Meaning no external feedback is necessary to make it work at divide by 5/10.
The 74XX161/74XX163 can only divide by powers of 2 at maximum clock rate. You have to add feedback to divide by 5 and THAT is what slows it down so much. Dividing by 10 is even slower in most logic families. There is also 74XX190 series. Rick N6RK On 7/11/2020 3:00 PM, Perry Sandeen via time-nuts wrote:
Learned List, On previous posts I was looking for a PDIP package 100 MHz decade divider. Reading just the front of the data sheet I thought that the 74LS161 would work. Boy, was I wrong. Several members posted that 25 Mhz max was its limit. So *on the road again* (sorry Willie) I went on another search this time with the correct logic family. It turns out Arrow carries the 74HC161 for less that $1. Additionally I D/L'd the Charles Wenzel Unusual Frequency Dividers PDF and discovered a 100 MHz decade divider circuit using 1/2 of a 74HC74 in a configuration that will decade divide up to 300 MHz. I'm attaching a copy of the circuit for anyone interested. Regards, Perrier _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
_______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
