Hello,
I would like to have some advice, I use the CODEC SGTL 5000 with a microphone input. Should I enter a signal with an offset (+1.5V and -1.5V) or without an offset (+3V)?
Thank you in advance for your helps.
Regards
Dear Yann,
please see below an answer from an application engineer I have contacted. Please make sure you do not exceed the maximum ratings stated in the SGTL5000 datasheet. Otherwise the component will be damaged.
DESCRIPTION
The Mic input pin should not have minus voltage, otherwise it may damage. So customer could input voltage above 0V on Mic input pin.
With Best Regards,
Jozef
Hello Jozef,
Thank you for your answer but I think your answer is probably wrong.
'So customer could input voltage above 0V on Mic input pin'
After the capacitor C7 you no longer have an offset.
Thus you'll have this configuration at the input of MIC (pin 10). Yes you're right about the maxi value which should not exceed 2.83 pp V.
Hello Yann,
yes, you are right, the bias voltage should move the signal to the positive voltage. Alternatively you can add there a diode to create a clamper circuit, to make sure, that the voltage will not drop below 0V. But I am not sure how it will influence the signal.
Still please test first to apply positive signal on the MIC pin and you can then step be step move the signal below 0V.
With Best Regards,
Jozef
