Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

MEMS microphones Forum Discussions

senSR
Level 1
Level 1
First reply posted First question asked Welcome!

Hello,

I would like to use the IM73A135 analog MEMS microphone in a single-ended configuration.

I suppose that in order to implement this, I should either:
1. Use only one of the differential outputs, but which one?
2. Convert the two differential outputs into a single ended signal using an op-amp, but how does this circuit look like?

Considering the datasheet only mentions the characteristics when used in a differential configuration, I wonder how they change if I chose the first option - to only use one of the differential outputs.
Will the SNR and sensitivity change, or will they stay the same?

The second option of converting the differential signal into a single ended signal using an op-amp circuit intuitively seems like the "more correct" idea. Both the SNR and sensitivity should inherently remain the same, right?

The goal is to replace the single-ended microphone in our circuit with the IM73A135 because of it's higher SNR.
This is our original TI TLV342S op-amp circuit, ideally there is a way to convert it to support a differential input.

opamp_circuit.PNGIf you know about anything that might help, please let me know.

0 Likes
3 Replies
GeorgeT
Moderator
Moderator
Moderator
50 solutions authored 25 likes received 5 likes given

Hi @senSR ,

It is not recommended to use the microphone in the single ended mode as it does not offer protection against disturbances. If really required one of the differential output can be used and the other can be grounded. SNR and sensitivity values given in the datasheet are for differential mode and is not tested for the single ended mode.

Another recommendation is to use IM68A130 which is single ended output microphone and will be released soon. Please check the website to get updated on the release.

Thanks and regards,

George

0 Likes
senSR
Level 1
Level 1
First reply posted First question asked Welcome!

Hi George,

Thank you very much for the quick reply.

Will the IM68A130 also be IP57 water and dust resistant?
Will it also have a normal and a low power mode that switch depending on the supply voltage?
Do you have any info regarding it's availability and release dates?
Are there any samples available for our development purposes?

We need to know this in order to adjust our project timelines.

0 Likes
GeorgeT
Moderator
Moderator
Moderator
50 solutions authored 25 likes received 5 likes given

Hi @senSR ,

IM68A130 also offers similar robustness against dust and water. The microphone has only one operating mode and basic specifications are available in the product page. The microphone is supposed to be released to the market by the first quarter end of 2023.

Thanks and regards,

George 

0 Likes