I have many (up to 16) 8-channel "buses" (not digital, but analog) each with signals which I want to read with a single 8-channel analog-to-digital converter (ADC). I would switch between these ~16 buses at about 1 Hz and measure their 8 channels simultaneously with the ADC card. I'm trying to find an IC that might do something like this.

I know there are many single-channel and dual-channel multiplexer chips available, but I'm looking for one that can switch between sets of eight. Is there any hope that such an IC exists that can do this? I realise such a chip could have hundreds of pins. The alternative is to wire up 8 of these single- or 4 of these dual-channel multiplexers in parallel, which will likely require many board layers to avoid overlapping copper traces.

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    \$\begingroup\$ Have a look at analog cross-point (or cross-bar) switches from people like Analog Devices. Performance wise they will be over-kill for your application and possibly too expensive, but if you must have a single chip it may be the only solution. \$\endgroup\$ – Steve G Aug 6 '19 at 14:25

I would suggest multiple 8-input ADCs instead, such as MCP3208, which is an 8-input ADC with SPI interface. Layout would be simpler: connector to chip, then parallel SCK/MOSI/MISO 16 chips in parallel, and 2 shift registers to create the 16 chip selects. Only need 4 pins from microprocessor to control them all.

Will keep your incoming signals cleaner too, not all overlapping each other trying to feed into a single chip. Just a short trace from the connector to the MCP3208.

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  • \$\begingroup\$ Thanks. I had hoped to keep it to one ADC (it's a serial connected one, so I'd need to daisy-chain them or use many serial ports on the host), but it looks like parts to do many-channel parallel multiplexing don't exist. \$\endgroup\$ – Sean Aug 9 '19 at 15:17

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