Description

000034504 - Design Advisory for Zynq UltraScale+ MPSoC/RFSoC – PS MIO might glitch High during power-up

Release Date
2022-10-28
Revision
1.0 English

The Zynq UltraScale+ PS MIO might output a High glitch during the power-up ramp of the VCCO_PSMIO supply.

If the issue occurs, the MIO has been observed to begin driving High when the VCCO_PSMIO supply ramps to 0.4V-0.5V and continues to drive High until the VCCO_PSMIO reaches 0.6V – 1.1V, before the MIO returns to a high-impedance state.

Actual occurrence on a specific device or specific MIO is non-deterministic and the actual output glitch profile likely depends on the device/MIO, temperature and VCCO_PSMIO power ramp profile. See the example MIO glitch shown in the yellow waveform below where the blue waveform is the example VCCO_PSMIO ramp.

No settings or reasonable external pull-down can control/overcome this output glitch.

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Configurations Affected:

The issue affects PS MIO's that are either pulled low or high impedance on start-up. PS MIO in all Zynq UltraScale+ MPSoC and Zynq UltraScale+ RFSoC devices can exhibit this issue. The occurrence of the issue is not deterministic.

In one study, the issue occurred in ~75% of devices and, in affected devices, the issue occurred on 10-33% of MIO, depending on the device and condition.

The issue can occur during the VCCO_PSMIO ramp of the recommended power-on sequence. Alternate power-on sequences might incur other kinds of glitches due to non-deterministic values of internal control logic.

Impact: The MIO glitch might incur signal contention, including to bused signals, or cause other devices to detect a temporary High from a connected Zynq UltraScale+ PS MIO.