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TLV3501: Connecting VCC to 0 V and GND to -5V

Vadim Berdichevsky
Prodigy 60 points
Part Number: TLV3501
Other Parts Discussed in Thread: TINA-TI

Hi,

I want to connect the GND pin of TLV3501 to -5V. The VCC will be connected to 0V (thus, the voltage between VCC to GND is still +5V as specified in the datasheet).

In my understanding it should work, isn't it? Of course, all the other pins of the TLV3501 will be also referenced to the GND pin voltage: the SHDN pin will be connected to GND (-5V), and the inputs will be between 0V to -5V.

The problem is that it doesn't work in SPICE (I have tested it with Micro-cap program, I do not have the TINA-TI). Is it just a problem with your SPICE model of the TLV3501, or maybe I am wrong and my connection is illegal?

A screenshot of my SPICE results (DC operating point analysis) attached below: GND (pin2) and SHDN (pin6) are at -5V. VCC (pin4) is at 0V. The negative input is higher than the positive, so I am expecting that the output of the comparator will be at GND (which is -5V), but instead I get 0V.

Best regards,

Vadim.

  • 0
    TI__Mastermind 25970 points

    Vadim

    I checked on TINA as well.  I only get the model to work if you use split supplies like +/-2.5V.  I even tried +1/-4V and that worked but 0V/-5V would not work properly.  So it must be something in the model.  We will put in for the model to be updated to allow this simulation use case.

    Regardless of the modeling problem, what you have proposed is an acceptable usage case.  The voltages at V+ and V- can be any value as long as VS is in the range of 2.2V to 5.5V.

    Chuck