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8+ channel ADC


#1

Hi, has anyone looked for an 8+ channel ADC chip? I don’t need any great change in resolution than the inbuilt ADCs give but I need lots of channels.


#2

Yikes, those things are expensive. You’re also looking at QFP, QFN, or BGA packaging, it looks like. Are you expecting to pay $50+ per chip for 8 10-bit channels?


#3

ok, looks like I’ll be searching for several 2-ch ADC devices then :slight_smile: I wasn’t “expecting” to pay that, but the tradeoff I guess is whether it’ll be easy or not - perhaps a massively parallel USBizi board will be borne from this - link a few Pandas as the prototype, and then custom make a board. When I say it like that it sounds like it might even be achievable.


#4

Well, there’s 6 in the LPC2387, 5 of which are exposed by the USBizi chipset. Certainly cheaper per ADC input than what Digikey has available.


#5

Can’t you use 1 ADC and a analog multiplexer instead?


#6

my thought on using a mux was that i needed to be really careful with traces and routing, and since I’m hand-making the board (perhaps on perfboard) that may be problematic. But it has been something I’ve thought of.


#7

8+ channel ADCs are all over and not that expensive. Go to Maxim’s parametric search, pick 10 or 12 bits, and all the 8+ channel options.


#8

Call me a lair, but Maxim’s 8 channel ADCs are rarely pref board friendly… :slight_smile:

At the frequencies applicable here you don’t have to worry about trace lengths at all. Look at 4051. It’s an 1 to 8 analog multiplexer.


#9

I use Analog Devices ADG407BNZ 8 to 1 multiplexers with very good results. Feed them to a 595 to read thermocouples. They have been rock solid for the last six months or so. That will get you 48 channels on a panda II if you need them…