PCM1820-Q1: For the PCM1820 ADC output, the code range (2's compliment) for the negative voltage range does it include the negative values?

TI support,

Thank you for the quick response. Regarding the output...I understand. Is the THS4561 FDA a viable/appropriate front-end interface for the PCM1820 ADC?

Hi Philip,

Most differential op-amps, including the THS4561, can serve as the front-end to an ADC so as long as the input signal range is within our specified limits; i.e 2Vrms and doesn't exceed maximum ratings.

Can you help me understand your signal flow? In your use case is it  Analog Microphone>THS4561>PCM1820-Q1>?

Regards,

Daveon, It doesn't sound like you have a very high degree on confidence in answering this question. To help, if you refer to In the application note (SBAA246A–January 2018–Revised March 2019), on page 1. I am using a single-ended signal into the THS4561.

I have a non-inverting follower (same as the example app-note SBAA246A). Vocm is set to 1.65V, and I have a voltage swing of 2.9V, and the THS4561 is set up 1V/V (gain of 1). Something I wanted to recheck with you about the data code out of the PCM1820. It appears to using I2S format it states the the data is 2's compliment (TI app note, SLAA469–September 2010), mentioned in a previous support link. https://e2e.ti.com/support/audio-group/audio/f/audio-forum/448767/3254-serial-data-format-signed-unsigned.

These are 2 different ADC, PCM1820 is audio ADC and the ADS7057 is general purpose ADC, both are with 2's complement.

Your level of 2.9Vpp (~1Vrms) should be ok for this PCM1820 input.