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LMP91000: storage time vs operating life

Vincenzo Pizzolante
Mastermind 25486 points
Part Number: LMP91000

hi,

we are currently working on new battery powered Electrochemical gas sensor board, and plan to use LMP91000.

As stated that IC have internal switch, which can connect RE and WE electrodes of Gas sensor when A1 and TIA is OFF.

And when the board is unpowered (at battery replacement time), additional external J-FET shorts RE to WE.

In the beginning I thought that when sensor is unpowered (TIA disabled, RE & WE connected together), it would require A1 to be enabled if we don't want to wait powering ON the sensor (for sensor stabilisation). 

Later on I realized that sensor doesn't require any stabilisation time when LMP91000 switches from "DeepSleep" mode to "Amperometric" mode, because CE doesn't require any current to flow in/out to enshure that voltage at RE equals WE.

This state is the same as it was during sensor storage (when RE and WE is connected by spring). But sensor manufacturer usually state storage time as twice smaller than operating life. Is it due by shorting RE and WE pins? If this is the case, then the time between measurements (once every10 minutes) will degrade sensor performance?

thanks a lot in advance

KR

Vincenzo

  • 0
    TI__Genius 9675 points

    Hi Vicenzo,

    I will look into this and get back with you.

    Jalen

  • 0 in reply to Jalen Tate89
    TI__Genius 9675 points

    Vicenzo,

    In deep sleep mode, the TIA and A1 control amplifier are both off. The mode of operation is suggested when the gas detector is not used and a zero bias is required between WE and RE electrodes of the gas sensor.

    In standby mode, the TIA is off, while the A1 control amplifier is ON. This mode of operation is suggested when the gas detector is not used for a short amount of time and a faster warm-up of the gas detector is required.

    As far as the sensor performance, please check the datasheet of your sensor for any data on this. We cannot comment on sensor degradation/performance.

    Jalen