looking to see what the ma. output is for the 4017
i looked at the PDF files on the web, but i cannot find any info on what the max ma. output is for each output..
Depends on the Vdd voltage and temperature.
Sinking (output low) currents are:
5V Vdd and 85C sinking current is 0.42 ma.
10V Vdd and 85C, sinking current is 1.1 ma.
15V Vdd and 86C sinking current is 2.8 ma.
Sourcing (output is high) currents are:
5V Vdd and 85C, sourcing current is 0.42 ma.
10V Vdd and 85C, sourcing current is 1.1 ma.
15V Vdd and 85C, sourcing current is 2.8 ma.
Bear in mind that these current limits will vary with temperature, so they do son't apply at higher and lower temps.
TTL will give you higher currents - or you can also get an CMOS inverter chip tie all the outputs together and you'll have increased your load ability.
Just have to make sure there that the current draw won't go over the maximum limit.
If you need more than a couple lines driven, use a uln2803. no resisitors needed but sink only (low side driver). It can drive up to 500 mA on each output though you have to watch the heat. about $.50.
If you want to go to discrete transistor without resistors, you also have the choice of the 2N7000 or 2N7002 FET in a to92 package, good to a couple of hundred mA.
