LMP91000: How to configure LMP91000 for zero bias gas sensors.

HARI T O1

Expert 1645 points

Part Number: LMP91000
Other Parts Discussed in Thread: LMP91002, ASH

Tool/software:

Dear team,

May I know how to configure the LMP91000 bias voltage for zero bias gas sensors.

I use LMP91002 with this sensor from Alphasense.

Regards

Hari

4 months ago

0 Alex Thompson 4 months ago

TI__Genius 12195 points

Hari,

For non-biased gas sensors, you should use the LMP91002, it is specifically designed for non-biased sensors.

Regards

-Alex Thompson

0 HARI T O1 4 months ago in reply to Alex Thompson

Expert 1645 points

Hi Alex,

Thank you very much.

For zero bias gas sensors the voltage at the A1's non inverting pin should be zero.Please correct me if I am wrong.

May I know how to configure this.

This document contains the discrete implementation for zero bias gas sensors.

Regards

HARI

0 Alex Thompson 4 months ago in reply to HARI T O1

TI__Genius 12195 points

Hari,

This is correct, the CE pin should be at 0V since it is a zero-bias sensor.

Thanks for sharing that app note, it's very helpful!

Thanks

-Alex Thompson

0 HARI T O1 4 months ago in reply to Alex Thompson

Expert 1645 points

Hi Alex,

Do I need to make any register setting for making the bias voltage to zero.

I can see a reference divider and diagnostic blocks.

Or is it zero volt by default

Regards

HARI

0 Alex Thompson 4 months ago in reply to HARI T O1

TI__Genius 12195 points

Hari,

You should not need to set any registers or activate the diagnostic functions to achieve zero bias. It should be as simple as connecting the CE pin of the sensor to the CE pin of the LMP91002. It may be a case where the CE pin isn't forced to 0V but just isn't forced to any voltage. Just direct connection with no additional settings should be sufficient for the CE pin.

Thanks

-Alex Thompson

0 HARI T O1 4 months ago in reply to Alex Thompson

Expert 1645 points

Hi Alex,

Thanks for the confirmation.

""LMP91002 Configurable AFE for Low Power H2S and CO Sensing Applications"

I belive I can use it for other gases also.

I am working on a gas sensor node project which contains more than 16 gas sensors.

In this more than 8nos are electrochemical sensors with zero bias.

Below is the list of electrochemical gas sensors I am going to use.I believe this IC can be used for all not specific to H2S and CO

Chlor (Chlorine, Cl₂)	Alphasense CL2-A1	CL2-A1
Ethylenoxid (Ethylene Oxide)	Alphasense ETO-A1	ETO-A1
Schwefelwasserstoff (Hydrogen Sulfide, H₂S)	Alphasense H2S-A1	H2S-A1/H2S-D4
Cyanwasserstoff (Hydrogen Cyanide, HCN)	Alphasense HCN-A1	HCN-A1
Phosphin (Phosphine, PH₃)	Alphasense PH3-A1	PH3-A1
Aceton (Acetone)	Alphasense PIDX-A-4000	PIDX-A-4000
Schwefeldioxid (Sulfur Dioxide, SO₂)	Alphasense SO2-A4	SO2-A4
Arsin (Arsine, AsH₃)	ES4-AsH3-1	ES4-AsH3-1
Methylmercaptan (Methanethiol, CH₃SH)	ES4-CH4S-100	ES4-CH4S-100
Formaldehyd (Formaldehyde, HCHO)	Gravity Formaldehyde Sensor	Gravity HCHO
Tetra-Chlor-Ethylen (Tetrachloroethylene)	Ion Science MiniPID 2 HS	MiniPID 2 HS
Tri-Chlor-Ethan, 1,1,1- (Trichloroethane)	Ion Science MiniPID 2 HS	MiniPID 2 HS
Tri-Chlor-Ethylen (Trichloroethylene)	Ion Science MiniPID 2 HS	MiniPID 2 HS
Phosgen (Phosgene, COCl₂)	Sensorix COCl2	Sensorix COCl2
Hydrazin (Hydrazine, N₂H₄)	Sensorix N2H4 1	AN181400
Ammonia (NH₃)	SGX-4NH3-1000	SGX-4NH3-1000
Fluorwasserstoffsäure (Hydrogen Fluoride, HF)	SGX-HF-10	SGX-HF-10

0 HARI T O1 4 months ago in reply to Alex Thompson

Expert 1645 points

Hi Alex ,

Thank you.May I know this IC is specific to H2S and CO sensors.

Or I can use it with other zero bias electrochemical sensors also.

Regards

HARI

0 Alex Thompson 4 months ago in reply to HARI T O1

TI__Genius 12195 points

Hari,

This IC can be used with other zero bias electrochemical sensors, not just H2S and CO.

Thanks

-Alex Thompson

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LMP91000: How to configure LMP91000 for zero bias gas sensors.