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I'm in need of a replacement for the CA3080 for my VCO that I would like to build. I have come across the LM13600 and was wondering if anyone knew if I could just use half of it and operate it without connecting to the buffer pins (9,10).

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It looks pretty similar, provided you don't get too close to the supply rails (the LM13600 typically has a bit less input common mode range, and a bit less typical swing (both near the negative rail), but the guarantees are similar.

Why wouldn't you use the LM13700? It still seems to be in production, unlike the LM13600 (discontinued 1997) and CA3080 (discontinued 2005).

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  • \$\begingroup\$ Your right! That was an epic fail on my part! Both the LM13700 and LM13600 have the exact same layout and the actual text in the datasheet is almost identical. \$\endgroup\$ Feb 23 '14 at 4:54
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ABSOLUTELY!

The LM13600 and LM13700 started out life as a practice piece for a new mask designer. They were thinking about second-sourcing the CA3080, and the new 16-pin package made a dual CA3080 an easy exercise (just flip the layout to do the other side). They had a few pins left over, so they added the Darlington buffers and the predistortion diodes.

The key takeaway is that the LM13600 and the LM13700 are both dual CA3080s with a little something extra added, that you don't have to use if you don't want to.

Details here.

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    \$\begingroup\$ Thanks, that's interesting. If you're interested in that sort of thing, I can recommend the late Hans Camenzind's book (free download or buy paper version). designinganalogchips.com \$\endgroup\$ Feb 23 '14 at 15:01
  • \$\begingroup\$ the "simplified" schematic in both datasheet ( the CA3080 and LM13700 ) differ. \$\endgroup\$ Oct 13 at 2:23
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Yes, just tie the unused Non inverted / inverted pin to the negative power power rail.
the iABC pin via 1 Mega Ohm resistor to the negative power rail, the output of the buffer back the input of the buffer or leave it.

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