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LMP91000: Configurations

user5179595
Prodigy 80 points

Part Number: LMP91000

Dear Community,     

I am trying to configuration the lmp91000 for work with the sensors O2-M2 and ETO-A1 both of Alphasense.

The settings that I used for the sensor O2-M2 are as follows:

LMP91000_TIA_GAIN_350K | LMP91000_RLOAD_100OHM,
LMP91000_REF_SOURCE_INT | LMP91000_INT_Z_50PCT | LMP91000_BIAS_SIGN_POS | LMP91000_BIAS_0PCT,
LMP91000_FET_SHORT_DISABLED | LMP91000_OP_MODE_AMPEROMETRIC  

And the settings that I used for the sensor ETO-A1 are as follows:

LMP91000_TIA_GAIN_350K | LMP91000_RLOAD_33OHM,
LMP91000_REF_SOURCE_INT | LMP91000_INT_Z_50PCT | LMP91000_BIAS_SIGN_POS | LMP91000_BIAS_6PCT,
LMP91000_FET_SHORT_DISABLED | LMP91000_OP_MODE_AMPEROMETRIC 

My problems are the following:
I'm not sure the values for TIA_GAIN, REF_SOURCE, INT_Z and FET_SHORT, ¿how I can know the values for these parameters?

  • 0
    Guru 140200 points
    Hi User,

    maybe this helps:

    www.ti.com/.../snoa922

    Kai
  • 0
    TI__Genius 12780 points

    Hello,

    Please use our web bench tool located on the LMP91000 page (right hand side, about halfway down the page).

    If the sensor that you are using is not available in the menu, you may add a sensor, and input values from the sensor data sheet. This method will provide you with LMP91000 register values.

    The TIA_GAIN_350K will set the resistor value (multiplication factor) to multiply the current coming from the Working Electrode (Iwe), as seen at the output Vout. Vout=(Vref_divider) - (RTIA * Iwe).

    REF_SOURCE Internal uses VDD as the reference. REF_SOURCE External uses an external voltage.

    INT_Z is the voltage present between WE and Ground, and is a percentage of Vref.

    FET_SHORT should be left open. You can short when there is not any bias required for a sensor.

    Best Regards,

    Dan

  • 0 in reply to dBrock
    Prodigy 80 points

    I´m trying to open the software but don't works.

  • 0 in reply to user5179595
    TI__Genius 12780 points

    Hi user5179595,

    I am unable to view the image you attached. Could you please provide this in another format, or a separate attachment?

    When you click "Open Design" (see below)

    this will launch another window that looks like this (see below)

    Please ensure that your browser is not blocking pop-ups, and that Flash is enabled.

    Best Regards,

    Dan