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# THS4131: Error Calculation Of THS4131

Part Number: THS4131

hi every one i need to find out the total error at the output of Differential amplifier which is then fed in to ADC ADS8422.

input to diff amp is Vin +  = 5.46  and Vin- =-2.73.

could you please guide me to calculate the error at the output of Diff Amp and what is the effect at the same in  the ADC

Regards,

DNNNair

• Hi,

Can you please share what you mean by the error at the output? What are the supply voltages you are using and are the voltage values you shared DC voltages? Currently you will see a significant differential output cause by the approximately 8V differential signal you are showing.

Regards,

Jacob Freet
High Speed Amplifiers

• In reply to Jacob Freet:

Hi,
The voltage I shared is DC voltages only. I have to find out the DC output Error of this amplifier as well us , what is the effect of amplifier output if temperature increases . the same way have to calculate Error budget of ADC ADS8422.
the differential amplifier output is the input of ADC.

Regards,
DNNair
• In reply to Dipu N Nair:

Hi,

The amplifier is going to gain of the difference between the voltages by whatever gain you have the device configured in. For example if the device is in a gain of 2V/V the output will have over 16V differential. I would suggest setting the input pins to the same DC voltage value to avoid any differential output offsets.

Regards,

Jacob Freet
High Speed Amplifiers

• In reply to Jacob Freet:

Hi,

if we are using different Dc voltage at input pins. How to calculate Differential output offsets. What happens it with temperature.

Regards,
DNNair

• In reply to Dipu N Nair:

Hi,

The DC voltage difference between the pins will show up as a DC differential voltage at the output pins that is the value of the input differential voltage multiplied by the voltage gain. The value may change slightly with temperature based on the added offset voltage drift, but that would be a small percentage if you are using a large differential value.

Regards,

Jacob Freet
High Speed Amplifiers

• In reply to Jacob Freet:

hi,

thank you...!!!!! is that any problem may happen if change in temperature both ADC as well As Diff amplifier?

Regards,

DNNair

• In reply to Dipu N Nair:

Hi,

If you are using the ADC internal reference, there will be some drift that can occur over temperature. You will just need to make sure that your design accounts for the potential change in reference voltage.

Regards,

Jacob Freet
High Speed Amplifiers