AD7134 is not controlled through SPI

Hello,

Our customer is evaluating AD7134 for their seismic equipment

They use power supply AVDD5,DVDD5 - 5.04V

LDOIN,AVDD1V8,DVDD1V8,IOVDD - 1.81V external.

Pin 48,49 - 1.8V

Control via SPI from the microcontroller with using a 3.3 / 1.8V level converter

After the first power-up, the ADC is controlled well and behaves as described in the Datasheet.

But after about a week, the potential of pin4 (SDI) becomes equal to 0 and the IC can't be controlled. During this the ADC is working well - there is an output signal on pin10 (DOUT0). On pin12 (ODR) there is a 374KHz signal.

I also recommended the to look at the SPI Interface Lock/Unlock section in the datasheet however they can't write any symbols to the ADC.

What they do wrong?

Best Regards,

Evgeny Potemkin