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Original question:

ADS1234: voltage reference and analog input

ADS1234: ADS1234

Yakov Heifetz
Prodigy 30 points

Part Number: ADS1234

Tool/software:

The ADS1232 and ADS1234 ADCs from TI offer gain options of 1, 2, 64, and 128.
I am looking for another ADC from TI, specifically for strain measurement applications, that offers more gain step options, such as 1, 2, 4, 8, 16, 32, and up to 128.

Could you please suggest a suitable ADC model that meets these requirements?

Thank you in advance for your assistance.

  • 0
    TI__Prodigy 640 points

    Hello Yakov,

    The ADS1220 would be a good alternative to the ADS1232 . If more channels are needed, the ADS124S08 could be another potential option. Both ADCs support gain settings from 1 ,2 ,4 ,8 ,16 ,32 ,64 , to 128. Either ADC would be suitable for strain measurements. I have included a comparison table below.

    Parameter ADS1232 ADS1234 ADS1220 ADS124S08
    Description 24-Bit, 80SPS, 2-Ch (Differential), Pin-Programmable Delta-Sigma ADC for Bridge Sensors 24-Bit, 80SPS, 4-Ch (Differential), Pin-Programmable Delta-Sigma ADC for Bridge Sensors 24-bit, 2-kSPS, four-channel, low-power, delta-sigma ADC with PGA, VREF, SPI and two IDACs 24-bit, 4-kSPS, 12-ch delta-sigma ADC with PGA and voltage reference for sensor measurement
    Resolution (Bits) 24 24 24 24
    Sample rate (max) (ksps) 0.08 0.08 2 4
    Number of input channels 2 4 4 12
    Interface type SPI SPI SPI SPI
    Architecture Delta-Sigma Delta-Sigma Delta-Sigma Delta-Sigma
    Input type Differential Differential Differential/Single-ended Differential/Single-ended
    Multichannel configuration Multiplexed Multiplexed Multiplexed Multiplexed
    Rating Catalog Catalog Catalog Catalog
    Reference mode External External External/Internal/Supply External/Internal
    Features 50/60 Hz Rejection/Oscillator/PGA 50/60 Hz Rejection/Oscillator/PGA 50/60 Hz Rejection/Excitation Current Sources (iDACs)/Oscillator/PGA/Temp Sensor 50/60 Hz Rejection/Excitation Current Sources (iDACs)/GPIO/Oscillator/PGA/Temp Sensor
    Operating temperature range (°C) -40 to 105 -40 to 105 -40 to 125 -50 to 125
    Package type TSSOP TSSOP TSSOP/VQFN TQFP/VQFN
    Pin count 24 28 16 32
    Package area (mm^2) 49.9 62.1 12.25/32 25/49
    Package size (L x W) (mm) 7.8 x 6.4 9.7 x 6.4 3.5 x 3.5/5 x 6.4 5 x 5/7 x 7
    Power consumption (typ) (mW) 4.3 4.3 1.4 1.8
    Status ACTIVE ACTIVE ACTIVE ACTIVE

    Regards,

    Jiyah

  • 0 in reply to Jiyah Starks
    Prodigy 30 points

    Thank you for the information.
    I have another question.

    My bridge output at maximum operation is 32 mV/V with an excitation voltage of 2.5 V, which means the maximum input voltage to the ADC (Vin_max) is 80 mV.

    When using the ADS12S08 with a gain of 32, the VAINP requirement, according to the formula in section 9.3.2.1(PGA input -Voltage requirements) is greater than 1.4 V.

    How can I use an excitation voltage of 2.5 V or less while ensuring that VAINP remains greater than 1.4v?