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ADS1118: External pull-up resistance value range

Part Number: ADS1118

Hello,

I am using SPI for both the ADS1118 and a digital potentiometer. The digital potentiometer required an external pull-up resistor on the DOUT line, which means the ADS1118 DOUT line will also be pulled up externally in addition to the weak internal 400k Ohm pull-up. Will this create any issues. The value for the external resistor we plan to use is in the range of 2.2k to 5k.

Thank you very much!

  • Maggie,

    We don't have any specific information on pull-up resistors for the digital interface. However, in out devices, the output pins are often tested with load just to ensure that there is enough drive from the device to connect with the SPI master.

    Looking at the datasheet, the DOUT is tested with a 1mA load as listed in the electrical characteristics table:

    This means that if the supply is 3.3V, then a 3.3kΩ pull-up on DOUT should be fine. If the pull up resistor is a lower value, the device might have a more difficult time pulling the output voltage low.

    Joseph Wu