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# INA116: INA116P

Part Number: INA116

Hallo everybody ,

i want to know how much is the input offset Voltage when the Temperature more than 25 degree .

in the Specification section of Datasheet says to "See the typical curve", but there is no curve given in the data sheet.

Could you please help me to find how much is the input offset voltage when the temperature is 50 degree?

Thanks,

• Hi Sami,

The voltage offset drift will be different for every INA116 so the input offset voltage at 50°C will be different for each device as well. The datasheet provides a histogram graph in the Typical Performance Curves section that can help you gauge the amount of offset voltage drift that might be expected. I have copied that graph below. Note that the drift changes with the gain setting.

Say for example that the gain is set to 1 V/V. The lower histogram represents the drift that gain. The majority of the devices (18) are in a bin spanning a range of about 5 uV/°C to 15 uV/°C, with 10 uV/°C in the center. Changing temperature from 25°C to 50°C is a +25° change. Then for a 10 uV/°C drift and +25° change, the offset change could be +250 uV. If the initial offset is +500 uV at 25°C, then for this example the offset would be +750 uV at 50°C. Since the histogram spans both positive and negative drift ranges the drift could be negative as well.

Certainly it makes sense to do a worst case analysis in which for the G = 1 V/V spans from -60 uV/°C to +80 uV/°C. Using the same method of calculation as above, the offset contribution due to drift could range from -3 mV to +4 mV. In reality, the histogram is based on drifting the INA116 device over the full specification temperature range of -40°C to +85°C, whereas your temperature change is from +25°C to +50°C. The wider temperature range is often a more extreme case for drift than what is observed over a narrower temperature range. Nevertheless, the worst case is exactly that and the drift is unlikely to be that high over the narrower temperature range.

Regards, Thomas

Precision Amplifiers Applications Engineering

• Hi,

Regards,
Sami
• HI,

I want to use INA116 for a pH measurement application.
From the data sheet of INA116 I found that there are two variants (INA116P,U and INA116PA,UA)
For my project, I need to use INA116U variant.
I checked with different supplier web sites, but I could only find INA116UA. Could you please suggest me where I can order this specific variant or if there is an alternative with the same specification.

Thanks

Regards,
Sami
• Hello Sami,

I did some research into the INA116U, which was the high-grade INA116 variant, and unfortunately it has been discontinued and it appears our datasheet has not been updated to reflect this. I apologize for the confusion.

Unfortunately, the INA116 is unique in our instrumentation amplifier portfolio by virtue of its extremely low input bias current, so we don't have an exact replacement for the INA116U variant at this time.

However, it is possible that we have another device in our portfolio that may meet your design needs. A few questions:

1) Do you require fA levels of input bias current, or can you accept a higher Ib spec?
2) What separates the high grade INA116U from the standard grade INA116UA is DC precision, namely input offset voltage and drift over temperature. What levels of offset and drift can your design tolerate?

Thank you for any information you can provide, and I look forward to helping you find a suitable instrumentation amplifier for your design.

Christopher Stemple
Precision Amplifiers Marketing