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TLV2553: ADC test modes, how can they prove the ADC VREF is still connected and in spec?

Relay Man
Prodigy 70 points
Part Number: TLV2553


Hi,

I see this converter has the test modes shown below, can these be used to show if the VREF is still connected and in spec?

1011b Bh SELECT TEST, Voltage = (VREF+ + VREF–)/2

1100b Ch SELECT TEST, Voltage = REFM

1101b Dh SELECT TEST, Voltage = REFP

  • 0
    TI__Genius 16890 points

    Hi James,

    The TLV2553 is using the input reference voltage as the input to the ADC.  It uses the self test block to make a 1/2 reference voltage and then sends this voltage and the REF+ and REF- voltages to the ADC.  This will show that there is a reference voltage at the reference input pins.  It does not tell you anything about the magnitude of the reference voltage though because the input (which comes from the reference) is being compared to the reference.  For example, if you do the REFP test you will get 4095 if your reference is 3V or 5V.


    Mike

  • 0 in reply to Michael Stout
    Prodigy 70 points

    Hi,

    Could you let me know what happens to the three values should the reference be disconnected?

    Thanks

  • 0 in reply to Relay Man
    TI__Genius 16890 points

    Hi James,


    It will take me a couple of days to get an EVM and then I can measure that.


    Mike