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TLV3701-Q1: Common mode input voltage issue

Eric Sterckx
Prodigy 10 points

Part Number: TLV3701-Q1
Other Parts Discussed in Thread: TLV1851-Q1

Tool/software:

The datasheet states (clearly) that the device's input common mode range extends up to Vcc + 5V. But not a single performance graph or specification mentions operation with a common mode above Vcc.
Moreover, on page 2, the datasheet states:
"For harsh environments, the inputs can be taken 5 V above the positive supply rail without damage to the device."
To, this sounds like a guarantee of survival, not of correct operation.
I have the impression that the author of the datasheet has confused input voltage range and common mode range.
Can you please clarify?
More precisely, I wonder if the circuit below will always generate a high output if the node at P517 goes above +5V (while staying within the Vcc+5V range).
Best regards,

Eric


  • 0
    Guru 321020 points

    The VCC + 5 V limit is specified in the recommended operating conditions.

    Your circuit will work.

  • 0 in reply to Clemens Ladisch
    Prodigy 10 points

    Thanks for the valuable tip about the hysteresis. I should have thought about this.
    Basically, your answer to my main question is:
    Because the input common mode voltage is within the recommended operation conditions, the circuit will work, even if no example is shown in the datasheet.
    Good for me then. Thanks!

  • 0 in reply to Eric Sterckx
    TI__Genius 13225 points

    Hi Eric,

    I apologize for the confusion. This device is old, and the datasheet hasn't been revised in a while. Your circuit would work as the TLV3701-Q1 has over-the-rail operation, which means the inputs can go over the rail (VCC < VIN < VCC + 5V) and still have the correct output.

    For newer designs, we recommend using the TLV1851-Q1, which is a drop-in replacement with upgraded functionality as compared to the TLV3701-Q1. TLV1851-Q1 can have both inputs go 40V above V- and still operate properly.