Texas Instruments TMS320F28004 Series, Руководство пользователя

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Advisory GPIO: Parasitic Path to V
SS
When Maximum V
IH
is Exceeded in Input Mode
Revision Affected A
Details If a voltage greater than maximum V
IH
(V
DDIO
+ 0.3 V) is applied to the GPIO pins listed
below, an internal parasitic path from the pin to V
SS
may be turned on. This parasitic
current can impact the functional operation of the pin. This is more likely to occur at high
temperature. The parasitic path will be removed when the IO is driven below V
IL
. The path
will not reactivate until another overvoltage event occurs.
• GPIO16
• GPIO17
• GPIO24
• GPIO25
• GPIO26
• GPIO27
• GPIO35 (TDI)
• GPIO37 (TDO)
• GPIO40
• GPIO41
• GPIO42
• GPIO43
Pins configured for output-only mode (with no other drivers on the pin) will not see an
overvoltage condition at the pin and are not affected by this advisory.
Pins configured in input or bidirectional mode can see an overvoltage condition in three
primary ways:
1. The input is driven by a low-impedance driver that can generate a large overshoot at
the input due to impedance mismatch without compensating termination.
2. The input sees large transients from external noise sources that rise above V
DDIO
+
0.3 V at the pin.
3. The input is driven by a device powered by a different voltage regulator. When
receiving voltages from another voltage domain, the system design should always
keep voltages below maximum V
IH
. However, due to the increased possibility of the
voltage being temporarily greater than V
DDIO
+ 0.3 V due to a noise event or if there is
improper supply sequencing, then this advisory will apply.
Workaround If any of the above conditions apply for an input or bidirectional pin, insert a series resistor
between the signal and the input pin. The series resistor should be placed close to the
input pin.
If the overvoltage is due to overshoot (situations #1 or #2 above), a series resistor of
100 Ω or greater should be used.
If the overvoltage might be sustained (situation #3 above), a series resistor of 220 Ω or
greater should be used.
www.ti.com Silicon Revision A Usage Notes and Advisories
SPRZ439G – JANUARY 2017 – REVISED AUGUST 2022
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TMS320F28004x Real-Time MCUs Silicon Errata
Silicon Revisions B, A, 0
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