Timeline for Is there any surprises in using high bandwidth instrumentation amplifier
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
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| Aug 31, 2016 at 9:02 | comment | added | Grebu | If the priority is on the waveform shape the AR version of the AD8421 should be enough. That version only costs <6€ here (Mouser). So you probably saw and cited the pricing of the BR version. | |
| Aug 31, 2016 at 7:44 | answer | added | Andy aka | timeline score: 2 | |
| Aug 31, 2016 at 7:37 | comment | added | Hugoagogo | 100k would introduce a significant offset if the shunt is inserted on the high side of a device, assuming even a 3.3V circuit, that is 33uA which is pretty significant in terms of sleep currents. I would probably connect 0V on the circuit under test to J2- | |
| Aug 31, 2016 at 7:26 | comment | added | Bernie Nor | As long as that is true, you should be ok. I would put a resistor there in any case. Like a 100 k or so. Input pins without any ground reference is not good thing in my book. | |
| Aug 31, 2016 at 7:25 | comment | added | Hugoagogo | Why is that, from what I read as long as my shunt is within approx 2v of the rails it should work correctly. | |
| Aug 31, 2016 at 7:21 | comment | added | Bernie Nor | One gotch I can see. You need to tye at least one of the input pins (IN+ or IN-) to your (virtual) ground, that is pin 2 of J2. Ref page 22 of the datasheet. Your case is like the transformer or the thermocouple example. | |
| Aug 31, 2016 at 7:07 | history | asked | Hugoagogo | CC BY-SA 3.0 |