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Usage Notes and Known Design Exceptions to Functional Specifications

Advisory GPIO: GPIO38 and GPIO46 Shunt to V

Due to Fast Transient Sensitivity at High

Temperature

Revision(s) Affected 0, A, B

Details There is a potential temporary internal shunt to V

condition identified on pins GPIO38

and GPIO46. In this condition, an on-chip path to V

is turned on, which can bring down

the logic level of these pins below V

and V

. The condition can occur when the pin is

in input or output mode and with any of the alternate functions muxed on to this pin.

The condition is more likely to occur at high temperatures and has not been observed

below 85°C under normal operating use cases. The triggering event is dependent on

board design and the speed of signals switching on these pins, with fast-switching

transients more likely to induce the condition. The condition has only been observed

when the signal at the device pin has a rise time or fall time faster than 2 ns (measured

10% to 90% of V

DDIO

The condition will resolve upon toggle of the IO at a lower temperature.

Workaround(s) Try one of these two options:

• Option 1:

Avoid the use of these pins in the revisions affected.

• Option 2:

This condition is not seen on all products. Many PCB designs have enough

capacitance and slow enough edge rates that the condition does not occur. If the

application can be tested and functions correctly with the temperature margin above

the end-use temperature, then no action may be required. If the issue is seen or

additional margin is desired, then the following can be applied.

Place a capacitor of 56 pF or greater between each of these pins and ground, placed

as closely as possible to the device. This will slow down the fast transient seen by

the device and avoid triggering the condition. Larger capacitors will be more effective

at filtering the transient but must be balanced against the PCB level timing

requirements of these pins.

SPRZ357J–August 2011–Revised July 2014 F28M35x Concerto™ MCU Silicon Errata

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MAP electronics Cocerto-B Especificaciones Pagina 23