------Question for RT9123GQW-2C Please Put your question below------
Could you please confirm the following whether the RT9123 digital input pins
LRCK, BCK, DATA (I2S interface) and EN are 3.0 V tolerant when the digital supply (VDD18) is powered at 1.8 V and the MCU is powered at 3.0 V ? If these pins are not officially 3 V tolerant, is it acceptable to drive them from 3 V logic without increasing quiescent current or causing back-powering, for example via internal clamp diodes?
Thank you very much for your clarification.
Best regards,
Jan Kijonka
Checking on this. Will let you know when I have the answer.
Hi jan.kijonka ,
I see nothing in the documentation which would indicate that the RT9123 has 3V tolerant I/O.
They are powered by the 1.8V “Vdd18” rail, and nowhere in the datasheet does it mention tolerance of higher voltages on any I/O pins. Therefore, I don’t believe you can interface directly between a 3V MCU and the RT9123 without a level shifter of some sort in-between.
Alternatively, the TFA9879HN/N1,157 appears to be a similar product which does explicitly state that the inputs are 3.3V tolerant. Unfortunately, this part is currently in a “Not Recommended for New Designs” (NRND) status, so future supply may be limited at some point (no current time frame listed).
Other option:
SSM2518CBZ-R7 – Can power with DVDD up to 3.6V, so this can use same power rail as the MCU and avoid any compatibility issues.
