Timeline for Analog switch on an instrumentation amplifier input
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 4, 2019 at 17:25 | vote | accept | Caleb Reister | ||
| Feb 2, 2019 at 6:00 | history | tweeted | twitter.com/StackElectronix/status/1091577097385111552 | ||
| Feb 2, 2019 at 0:31 | comment | added | D.A.S. | In order to optimize the Mux, you must consider the signal/Noise ratio in your spec added to question. In your spec include cable length of each source, the signal and impedance levels. Thermocouples are near 0 Ohms and <1mV, mic’s have open drain with 10k pullup, etc. So to eliminate noise the common mode impedance must be low while differential Z much higher than source and may need to be buffered | |
| Feb 1, 2019 at 23:23 | answer | added | AnalogKid | timeline score: 2 | |
| Feb 1, 2019 at 22:57 | history | edited | Caleb Reister | CC BY-SA 4.0 |
added 270 characters in body
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| Feb 1, 2019 at 22:27 | comment | added | Caleb Reister | @Gonzik007 I'm mostly targeting my design mostly at high-impedance outputs such as condenser microphones, thermocouples, and RTDs; but I would like to be able to connect a reasonably long cable as well. Since this is a school project, it will be room temperature. I will be using the AD8253, which has a programmable gain of 1, 10, 100, and 1000. | |
| Feb 1, 2019 at 22:20 | comment | added | EasyOhm | What are the signals? What are your drivers like (output impedance)? What is the gain of your INA? Do you need room temperature or across the full range? The switch is 90ohm Ron inline for single supply btw. We need to know all those details to determine signal integrity. To answer your offset question. Looks like leakage from the switch is 1nA. The INA is 5nA nominal. Leakage should be same into both + and - inputs and not cause offset. | |
| Feb 1, 2019 at 22:20 | comment | added | Hearth | You'll have some problems. The datasheet for the ADG409 quotes an on-state resistance of 40Ω typical and 100Ω max, which will really throw off your termination impedances. | |
| Feb 1, 2019 at 22:03 | history | asked | Caleb Reister | CC BY-SA 4.0 |