AD7798: Electrostatic experiment of AD7798

Document created by analog-archivist Employee on Feb 23, 2016
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When we do electrostatic experiment, the part cannot convert.

 

the registers on board the AD7798 can be corrupted due to ESD. So, the
registers lose their contents and the SPI interface may become asynchronous. A
reset (32 1s) will correct this.

To prevent this from happening, the voltage on an analog input cannot go above
AVDD + 3.3V or below GND – 0.3V. The voltage on any digital input cannot go
above DVDD + 0.3V or below GND – 0.3V. If the voltage is outside these
conditions, the ESD diodes inside the AD7798 will turn on, current flows
through the AD7798 and the registers are corrupted. To prevent this, the
customer needs schottky diodes on the pins that are seeing the ESD. The
schottky diode will turn on when the voltage on any pin is 0.3V above AVDD or
DVDD.

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