hey there guys. i've been trying to simplify making a 6 digit countdown circuit. currently i'm using 40110's 1 per digit and it works great, but i'd like to cut it back even further and was wondering if anyone knew of a cmos ic that would be like the 4553 that would drive 3 digits at once but countdown, or could the 4553 countdown instead of up? i've looked at datasheets and from what i've gathered it only counts up. i'm hoping i'm wrong. either way some advice would be great thanks!

 

The 4553 can only count up.

The 40110 is about as simple as you can do. Even if the 4553 would count down, you would still need a BCD to 7-segment decoder for each digit.

 

<snip> Even if the 4553 would count down, you would still need a BCD to 7-segment decoder for each digit.

Have a look at the 4543. Motorola/OnSemi's datasheet for the MC14553 has a diagram for a six digit up-counter using two 4553's, two 4543's, and three transistors on page 6:
http://www.onsemi.com/pub_link/Collateral/MC14553B-D.PDF