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ADS64XX Pin Configuration (CFG Pin) Voltages

BJC
Prodigy 20 points
Other Parts Discussed in Thread: ADS6422, ADS6445

Hi,

We are using the ADS6422 12 bit ADC and are using the pin programming mode. What are the correct voltage levels for the multi-level programming pins CFG 1-4 and SEN?

The ADS642x datasheet from the T.I. website (June 2007) specifies VDD, 5/8 VDD, 3/8 VDD or GND.

Another post for the ADS644x states that the voltages should be VDD, 5/6, 3/6 and GND (and that the ADS642x datasheet still needs to be updated - which it does). The ADS644x datasheet has been revised with these values for the CFG pins but still specifies the VDD, 5/8, 3/8, GND for the SEN pin.

The ADS64XX EVM Users manual (SLAU196) schematic indicates settings of VDD, 2/3 VDD, 1/3 VDD or GND (implemented with three 1Kohm resistor divider and jumpers) for CFG pins and SEN pin.

Which are the correct values to use for the ADS6422?

Thanks,

Bert

  • 0
    TI__Mastermind 29220 points

    Hi,

    The correct voltage levels are VDD, 5/6VDD, 3/6VDD, GND.  The ADS6445 datasheet has this correct and some of the other datsheets in this family of devices still need to be updated.  I will ask this week about getting this started.

    The EVMs have the configuration resistors in the bill of materials as 1K over 2K over 3K but the User Guide was created before these values were settled on.

    The SEN pin does not have the same voltage settings as the four CFG pins - the SEN pin is still VDD, 5/8VDD, 3/8VDD and GND.  The CFG pins had some circuitry related to ESD protection that threw off the trip voltages from what was originally desired, but the SEN pin did not suffer that same effect and so the SEN pin did not need to have any datasheet edits to its voltage levels.

    Regards,

    Richard P.