STM32H747XIH6 DAC Issue

Samudra · ‎2025-09-29

We used a DAC with a sample-and-hold circuit on one of our custom boards. The RC filter was not mounted; instead, the DAC output was directly connected to an SMA connector. We enabled the DAC in the firmware, and after testing, we observed a large amount of current flowing through the STM32 board. Upon inspection, we found a short between the 3.3V rail and ground on the STM32 board.

Please find the attachment for your reference.

mƎALLEm · ‎2025-09-30

Hello,

which DAC instance?

R132 (0 ohm) fitted? (Short circuit on DAC1 output).

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Samudra · ‎2025-09-30

Hai Sir,

DAC1_OUT1 is used. R132 is not mounted on the PCB, and the capacitor is also not mounted.

Still, we observed a short on 3V3. Can I mount R132 with a 5k resistor since it is connected to ground?

Please confirm.

Best regards,

Samudralankaiah.

mƎALLEm · ‎2025-09-30

Based on what you are saying now I don’t think the issue is coming from DAC1_OUT but from another stuff that I couldn’t determine based on the information you’ve provided at this stage.

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