• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 46 subscribers
  • Views 187 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS1251: Recommended reference voltage

Noriyuki Takahashi
Genius 10180 points
Part Number: ADS1251
Other Parts Discussed in Thread: REF5025, ADS1260

Hi team

What is the recommended reference voltage of ADS1251?

I mean, it seems that 4.096V is recommended as the reference voltage. So if the reference voltage is 1.5V or 2.5V, are there any differences compared to Vref=4.096V?

Could you also tell the best device that can meet requirements as below, if the device is better than ADS1251?

Resolution: 24bit

Conversion Rate: more than 20kHz

input type: differential

# of ch: 1

Regards,

Noriyuki Takahashi

  • 0
    TI__Mastermind 41851 points

    Hi Takahashi-san,

    There is nothing wrong with using a smaller reference voltage as the long as the ADC can support it. For the ADS1251, the ADC can support a reference voltage of 0.5V to VDD, so using 1.5V or 2.5V should be okay.

    However, some customers use a larger reference voltage e.g. 4.096V and then use a resistor divider to try to scale the reference voltage to a smaller, less-common value e.g. 1.35V. I would caution against this approach, as the divider circuit will introduce noise and degrade the overall measurement performance. But, if the customer chooses a REF5025 for example to get a 2.5V reference voltage, then this is okay.

    The customer can look at something like the ADS1260 for a next-generation version of the ADS1251. This is a 24-bit, 40kSPS delta-sigma ADC with 3 differential inputs instead of just one, but it also includes a 2.5V voltage reference and a low-noise PGA (which can be bypassed if the PGA is not used). The ADS1260 comes in a 5x5mm QFN package, so it is smaller than the ADS1251, and the ADS1260 is a similar price. If the customer has additional requirements please share them with us so we can make sure the ADS1260 is still the best option.

    -Bryan