1
\$\begingroup\$

Components data sheet can be confusing sometimes

Can anyone explain to me the difference between these counters 74LS196 and 74LS197 ? can they replace each other? can the 74LS197 perform better in the place of 74LS196 in case if they do replace each other? Other thing, I found 74S196 !! so is the LS is different than S version - all these components are discontinued long ago, so any specific replacement with the same pin out ?

thanks in advance

\$\endgroup\$
  • \$\begingroup\$ One has a Divide-by-Two & a Divide-by-Five, while the other has a Divide-by-Two and a Divide-by-Eight... \$\endgroup\$ – Tyler Aug 25 '16 at 19:21
  • \$\begingroup\$ So one can give you a full modulo-16 binary counter while the other will be limited in its counting states when both the internal counters are combined. \$\endgroup\$ – Harshad D Aug 25 '16 at 19:27
  • \$\begingroup\$ 74S will be about 2-3x as fast as 74LS, consuming 3-5x the power. \$\endgroup\$ – Brian Drummond Aug 25 '16 at 19:33
3
\$\begingroup\$

As the datasheet says, one (74LS196) is a divide by 10 counter the other one (74LS197) is a divde by 16 counter.

The SN54/74LS196 decade counter is partitioned into divide-by-two and divide-by-five sections which can be combined to count either in BCD (8, 4, 2, 1) sequence or in a bi-quinary mode producing a 50% duty cycle output. The SN54/74LS197 contains divide-by-two and divide-by-eight sections which can be combined to form a modulo-16 binary counter. ...

I.e.

  • the 74LS196 will count 0, 1, 2, 3, ..9, 0, 1, 2,...
  • the 74LS197 will count 0, 1, 2, 3, ..15,0, 1, 2,...

Note: The 74LS196 has also a bi-quinary mode counting 0, 2, 4, 6, 8, 1, 3, 5, 7, 9, 0,...

\$\endgroup\$
  • \$\begingroup\$ Great answer, so now its clear I can choose between the 2. \$\endgroup\$ – Mos Aug 26 '16 at 1:26
1
\$\begingroup\$

The 74S196 is a decade counter made using Schottky bipolar transistor technology. The 74LS196 is the same thing, but Low Power Schottky.

For modern CMOS parts, look for 74HC196 or 74AC196 (or other assortments of letters in the middle).

\$\endgroup\$
  • \$\begingroup\$ Very helpful answer and thanks for posting the replacements \$\endgroup\$ – Mos Aug 26 '16 at 1:25
  • \$\begingroup\$ You're welcome. However, after posting that, I looked on DigiKey for the HA or AC parts, and found that they apparently don't exist. \$\endgroup\$ – Peter Bennett Aug 26 '16 at 1:33
  • \$\begingroup\$ Me too I looked around but i couldn't find any with HC or AC, I just have to stick with the important IC 74LS196 even if they dont make them anymore, sometimes they pop here and there. \$\endgroup\$ – Mos Aug 26 '16 at 2:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.