MAX9814 is damaged

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SomchaiK
 
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MAX9814 is damaged

Post by SomchaiK »

Hello,

I am using MAX9814 and connect directly to ESP8266 on A0 pin then it's working fine but after 2 hours then MAX9814 is damaged, it looks like no signal from Out pin.

Here is my installation.
VDD = +5V
Gain = +5V
Out = A0 pin ( ESP8266)
AR = unconnect
GND = GND

Note: I have tried MAX9814 quantity 2 pcs then all is damaged, it's same problem.

everyone please help.

Thanks & Regards.

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adafruit_support_carter
 
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Re: MAX9814 is damaged

Post by adafruit_support_carter »

Are you somehow compensating for the ESP8266's limited range on the ADC? It's only 0 to 1V.

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SomchaiK
 
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Re: MAX9814 is damaged

Post by SomchaiK »

No, I do not any compensating for the ESP8266's limited range.
I am just reading the value on pin A0 only.
What do you mean 0 to 1V ?
Please advise.

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adafruit_support_carter
 
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Re: MAX9814 is damaged

Post by adafruit_support_carter »

The output of the MAX9814 is approximately 2V peak to peak centered around 1.25V. So roughly ranges from 0 to 3.3V.

See ESP8266 datasheet for details about its ADC.
https://www.espressif.com/en/products/socs/esp8266
The input range is 0 to 1V:
esp8266_adc.png
esp8266_adc.png (14.48 KiB) Viewed 126 times
So the MAX9814 can not be directly connected to the ESP8266 ADC input. The voltage level will need to be adjusted. Try using a voltage divider.

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SomchaiK
 
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Re: MAX9814 is damaged

Post by SomchaiK »

I see, I will try to adjust the voltage level by using a voltage divider as you advise then I will be shared the result soon.

Thanks

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adafruit_support_carter
 
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Re: MAX9814 is damaged

Post by adafruit_support_carter »

If you have another non-ESP8266 board, could also try using that. Just to test the basic expected MAX9814 behavior. Most board's ADC range is the same as their logic level. That 1V range ADC is sort of an ESP8266 specific feature.

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SomchaiK
 
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Re: MAX9814 is damaged

Post by SomchaiK »

Sorry for my confuse,
I see, I'm using Wemos D1 MINI ESP8266 board which it has already a potential divider as schematic below.

https://siytek.com/wp-content/uploads/2 ... webp/ngcb2

This means that the incoming voltage is divided up in the same ratio as the value of the resistors. Putting a 3.3V signal at A0 means that only 1V will be present at the TOUT pin.

The potential divider scales down a 0 to 3.3V input, to a 0 to 1.0V input suitable for the TOUT pin.

Going back to our ADC conversion, this means that on the Wemos D1 Mini we are converting a voltage of 0 to 3.3 volts, to a scale of 0 to 1023.

So, As my mention above that it means Max9814 can directly connected to A0 pin of Wemos D1 MINI board, Is it Right ?

If yes then I have still same question Why Max9814 is working fine with Wemos D1 MINI around 2-3 hours after that it's damaged.

Please advise.

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adafruit_support_carter
 
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Re: MAX9814 is damaged

Post by adafruit_support_carter »

Yep, that voltage divider should work.

What's your indication that there's 0 output from the mic? Are you directly monitoring the out pin with a scope of some kind? Or the code running on the ESP8266 stops working?

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SomchaiK
 
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Re: MAX9814 is damaged

Post by SomchaiK »

There is around 1.2 volte output from MAX9814 by using volte meter.
I haven't directly monitoring with scope yet, I will be more checking on this case.
No, The code running on ESP8266 is not stops working, it's working fine.
I will be check more device around MAX9814 to make sure the root cause is not from MAX9814.

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adafruit_support_carter
 
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Re: MAX9814 is damaged

Post by adafruit_support_carter »

A volt meter won't be able to show anything useful on the output. You'll need to either use an oscope or write a basic sketch that reads the analog input and sends the values to the Serial Monitor.

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SomchaiK
 
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Re: MAX9814 is damaged

Post by SomchaiK »

Ok, I will try.

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