ADS1120: Designing with ADS1120IRVAR

Shibin Varghese

Part Number: ADS1120
Other Parts Discussed in Thread: ADS1220

Hello Team,
I am planning to design a temperature measurement system using thermocouples.
I am planning to use ADS1120IRVAR.
The thermocouple will be a K-type thermocouple.
I want the best accuracy out of it.

Based on a brief reading of the datasheet, I understand we have a temperature sensor inside the ADS1120IRVAR IC used for cold junction compensation.

1). Is ADS1120IRVAR a good choice for our application?
2). Is there any options available for higher accuracy?

Looking for your response.

over 1 year ago

0 Dale Li over 1 year ago

TI__Mastermind 35570 points

Hi Shibin,

ADS1120 is very suitable for temperature measurement including thermocouple. If a higher resolution or performance is expected, ADS1220 is 24-bit and pin-pin compatible device with ADS1120. ADS124S06/08 is another option as well.

Regards,

Dale

0 Shibin Varghese over 1 year ago in reply to Dale Li

Intellectual 835 points

Hello Dale,
Thank you for your reply.
The ADS1220 is a 4-channel ADC and we only need a single-channel ADC.
And, neither ADS124S0 nor ADS12406/08 is available in Mouser or Digikey.

Currently, my circuit looks like this.
Please share your thought on the same.

The output of the opamps is connected to an ADC.
The 2.5V Vref is generated from a reference IC.
Another temperature sensor is used for cold junction compensation.

0 Shibin Varghese over 1 year ago in reply to Shibin Varghese

Intellectual 835 points

Hello Dale,
Awaiting your response

0 Dale Li over 1 year ago in reply to Shibin Varghese

TI__Mastermind 35570 points

Hi Shibin,

ADS1220 has a same structure as ADS1120 which has two differential input channels.

Regarding your circuit, is there any specific reason you are using two buffers on the input?

Regards,

Dale

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ADS1120: Designing with ADS1120IRVAR