Hello all,
I'm trying to figure out what is the difference between both IC's?

CD4020 is 14 stage binary counter with 12 outputs
CD4040 is 12 stage binary counter with 12 outputs.

Both have 12 outputs... shouldn't both be 12 stage counters?
CD4020 is missing Q2 and Q3, where are they?...

 

CD4020 is missing Q2 and Q3, where are they?..

They are hidden inside the chip and don't have their outputs brought out.

 

CD4020 is missing Q2 and Q3, where are they?...

Exactly.

They are both 16-pin chips.
Two pins are Vdd and Vss.
Two other pins are INPUT and RESET.
That leaves you with only 12 output pins.

CD4040 is a 12-stage divider. Hence 12 output pins.
CD4020 is a 14-stage divider. You have to omit two output stages. Hence you lose Q2 and Q3 but gain Q13 and Q14.

 

Makes sense... thank you for informing me..

 

The cd4040 is.really 11 stages. Q1 should be Q0. I know this because of making a modulo 60 counter. I had to AND Q6,Q5,Q4,and Q3 to reset the counter to 0 using diodes and a 10k resistor to positive. Anodes are connected to the resistor and cathodes go to the Q outputs. Where the anodes meet the resistor is connected to the reset pin and is the output which is only a short pulse as 60 switches to 0. This is my theory, I have to desolder the diode at Q2 and put it to Q6.

 

They have a different number of bits and expose different outputs:

 

The 4040 has all outputs brought out. The 4020 and 4060 (and the 4521) elect not to bring out every output in the binary sequence for two reasons: a) so the highest order output can be even higher; b) so pins can be used for other functions, like an internal oscillator.

Personally, I wish the 4060 had a few more skipped stages internally so the highest output was at least 2^15, if not 2^16. If it were 2^15, then the chip could turn a 32 kHz watch "crystal" into a 1 Hz squarewave in one part - a pretty handy thing. If they skipped another output and used the pin for an oscillator enable (like the 4017), that would make the part much easier to use as a gated oscillator, such as a loooong period monostable. If if if ...

Based on all of the things I've done with the 4060 in the past, my ideal part would have the power, oscillator, enable, and reset pins, the first two stage outputs Q1 and Q2 for deriving multiphase clocks, and then Q10 through Q16.

ak

 

With the cd4040 you have to AND Q6, Q5, Q4, Q3 and Q1 for a modulo 60 counter. The ANDed output would go to the reset pin and that would be the output. The 60th count is just a fraction of a second so you wouldn't be able to see it with a multimeter. Things seem incomprehensible because the unit 1 is seen as the belief of 0 or 2.

 

They have a different number of bits and expose different outputs:
View attachment 152565

Remember to subtract 1 from the queue numbers of the cd4040 . Q1 is Q0

 

Personally, I wish the 4060 had a few more skipped stages internally so the highest output was at least 2^15, if not 2^16. If it were 2^15, then the chip could turn a 32 kHz watch "crystal" into a 1 Hz squarewave in one part - a pretty handy thing.

Absolutely, snap! I ended up using a 4013 D-Type flip flop and 4060 to derive a 1Hz clock signal when I was making a clock. I searched everywhere for a chip that would do it in one, but couldn't find anything!

 

Absolutely, snap! I ended up using a 4013 D-Type flip flop and 4060 to derive a 1Hz clock signal when I was making a clock. I searched everywhere for a chip that would do it in one, but couldn't find anything!

The CD4521 is an oscillator plus a 24 stage divider. With different crystal freqs you can get 1 second, 1 minute, or 1 hour output frequencies.

ak

 

The CD4521 is an oscillator plus a 24 stage divider. With different crystal freqs you can get 1 second, 1 minute, or 1 hour output frequencies.

ak

Thanks, handy to know for future reference

 

The CD4521 is an oscillator plus a 24 stage divider. With different crystal freqs you can get 1 second, 1 minute, or 1 hour output frequencies.

Unfortunately you can't get a 1 second output with the common 32,768Hz crystal.

 

Unfortunately you can't get a 1 second output with the common 32,768Hz crystal.

Sad but true. And, a bit surprising given that the part has design features specifically optimized for low-power operation. If they had brought out Q15 and then jumped to Q19, it would have been a nice compliment to the 4060.

ak