Category: Hardware
Product Number: AD7606C-18
I am interfacing an AD7606 evaluation board with an STM32H753ZI in 16-bit parallel mode. The BUSY pin has permanently failed to assert (stuck at 0V), halting the read sequence.
Hardware & Power:
- Power: 5V AVCC supplied via a 9V external charger; 3.3V VDRIVE supplied by the STM32.
- Context: The board was recently exposed to live-switching and transients from 50A/50mA current transformers (terminated with a 100-ohm burden resistor).
Diagnostics Performed:
- DSO Verification: Confirmed a clean 3.3V to 0V CNVST pulse reaches the ADC, but BUSY remains a flatline 0V.
- Continuity: The PCB track from the BUSY header directly to the IC pin is perfectly intact.
- Resistance: VDRIVE to GND and AVCC to GND both measure ~4.5 MΩ, ruling out a hard short.
- Manual Trigger: Forcing the AD7606 awake and manually toggling CNVST yields absolutely no voltage fluctuation on BUSY.
Given the intact tracks and nominal resistances, I suspect the internal conversion state machine or output buffer was destroyed via latch-up from the CT transients.
Has the ADI support team encountered this specific failure mode where the digital trigger logic dies but the power rails survive? Are there any final IC-level diagnostics to run before I desolder and replace the chip?
Athul E
