Dear Technical Support Team,
Ramp up of HVDD and HVSS are small voltage(±3V) as long as 3ms on powerup. After supplied AVDD and DVDD completely, HVDD and HVSS are supplied ±15V.
I guess that it is caused by ESD structure between AVDD and HVDD on datasheet.
Are the IHVDD and IHVSS increasing until supplied both AVDD and DVDD?
【Datasheet】
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The ADS85x8 require four separate supplies: an analog supply for the ADC (AVDD), the buffer I/O supply for the digital interface (DVDD), and the two high-voltage supplies driving the analog input circuitry (HVDD and HVSS). Generally, there are no specific requirements with regard to the power sequencing of the device. However, when HVDD is supplied before AVDD, the internal electrostatic discharge (ESD) structure conducts, increasing the IHVDD beyond the specified value until AVDD is applied.
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Best Regards,
ttd
