Are the internal clamping diodes on Intel® MAX® 10 or Intel® Cyclone® 10 LP devices active at all times?

The internal clamping diodes in the Intel® MAX® 10 and Intel® Cyclone® 10 LP devices are composed of circuits that are enabled only in a fully configured device. So unless the device is completely powered up and configured, the internal clamping diodes do not exist.

If while these devices are unconfigured, you are driving signals that require clamping diodes into them, in order to limit overshoot or undershoot use external clamping diodes to avoid damaging the device.

Refer to the following user guide and handbook:

• Intel® MAX® 10 General Purpose I/O User Guide section 2.3.2.7, PCI Clamp Diodes, and
• Intel® Cyclone® 10 LP Core Fabric and General Purpose I/Os Handbook section PCI Clamp Diode.

A note is planned to be added to future releases of both aformentioned documents.