1mv to 60mv gas sensor ADC suggestion required i2c preferred

Andrew Eve

Other Parts Discussed in Thread: ADS1115, ADS1114, ADS1220

Thank you in advance,

I am looking for a suitable adc with a pga capable of reading a gas sensor that give a 0-60mv range and I need two decimal places so I need 14bit (enob)? to give a 0.01 step in percentage between 0% and 100% gas concentration.

Many thanks

over 10 years ago

0 Gaven Liu over 10 years ago

Intellectual 300 points

As your requirement, You can try to evaluation the ADS1114/ADS1115, Included the internal programable gain Amplifier and internal reference. According your design, The System precision is decided by your Sensor. In this situation, the CMRR is, Fcm= 50HZ, DR = 8 sps, 105db.

0 Andrew Eve over 10 years ago in reply to Gaven Liu

Prodigy 30 points

Many thanks but page 13 of the datasheet shows the PGA gain maximum is 16 and my typical range for the sensor will be say 1mv to 40mv and this amplified at 16x will only bring my voltage to 16mv to 640mv so I will not be taking advantage of the whole range of the ADC.

Could I use a LM385P for instance to amplify the signal before the ads1114/5?

Kind regards

0 Andrew Eve over 10 years ago in reply to Andrew Eve

Prodigy 30 points

Sorry LM358P

0 Gaven Liu over 10 years ago in reply to Andrew Eve

Intellectual 300 points

I suggest you use the the other ADC, use one chip AFE can increase the stability and performance.

you can try the ADS1220.

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1mv to 60mv gas sensor ADC suggestion required i2c preferred