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ADS1293: ADS1293 voltage source

William Yu
Prodigy 80 points
Part Number: ADS1293
Other Parts Discussed in Thread: ADS1283

Hi team,

There are two LDO are used to supply the voltage of ADS1293 on EVM.

They provide VDD and VDDIO power respectively.

We have two questions regarding the voltage source.

(1)Could we use one LDO to supply VDD and VDDIO?
(2)Does the LDO that provides voltage to ADS1293 have PSRR requirement?
  • 0
    TI__Genius 11550 points

    Hi William,

    Thanks for the post and please see my comment for your questions below.

    (1)Could we use one LDO to supply VDD and VDDIO?

    In ADS1293, the VDD powers the analog portion of the device while the VDDIO powers the digital portion of the device. For the system which uses the same VDD and VDDIO, it will be fine to use one LDO for both supplies. You will need to make sure that the LDO is capable of sourcing enough current for both VDD and VDDIO. Please make sure to follow the filtering and decoupling recommended for the device, such as placing the local decoupling capacitors as close to the device's power pins as possible.

    (2)Does the LDO that provides voltage to ADS1293 have PSRR requirement?

    Even though the ADS1283 has a very good PSRR (80dB), it is still recommended to use a high PSRR LDO to suppress transient and further improve the overall PSRR of the system. I attached a link below to a blog that shows how to improve PSRR for an ADC system.

    Four ways to improve your ADC system power supply rejection

    Thanks.

    -TC