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ADS127L01: One ref for 12 ADC

Part Number: ADS127L01
Other Parts Discussed in Thread: REF6033, , REF6030, REF5030

Data converter team,

We have a customer who likes the performance of the ADS127L01, and is putting 12 of them on a board.  What would be the impact of using a single REF6030 or REF6033 for all 12 ADS127L01?

Can or should this be done?



  • Hi Darren,

    The REF60xx family cannot drive the DC input current of 12 ADS127L01 reference inputs.

    Depending on the CLK frequency, the reference input impedance of ADS127L01 will range between 2.2kohm (CLK=16MHz) and 4kohm (CLK=4MHz).  The REF60xx family is rated for 4mA max.  

    A quick calculation using the REF6030 (the maximum external reference voltage is 3V) and 12 ADS127L01's operating at 4MHz:

    Iload=12*(3V/4k) = 9mA

    I suggest using a single reference, such as REF5030, and adding a reference buffer for each ADC, similar to Figure 118 in the datasheet.

    Keith Nicholas
    Precision ADC Applications

  • Thank you very much, Keith.  I have a follow up question I'll post separately.