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Original question:

TMS320F280039: How to understand the min voltage spec of the Pin

TMS320F280039-Q1: GPIO Ptotection

Shri Ram
Intellectual 370 points

Part Number: TMS320F280039-Q1

Hi Team,

We are using TMS320F280039-Q1 as a controller for housekeeping operations. We have folling doubt. 

Do we have to provide overvoltage protection for GPIO and ADC pins, or is it already provided inside the chip?

If it is not provided, please suggest how to protect those pins from overvoltage, reverse voltage, and over current.

Regards,

Shri

  • 0
    TI__Genius 9430 points

    Hi Shri,

    The TMS320F280039-Q1 includes internal ESD protection and clamp structures on its GPIO and analog inputs. However, external protection is needed if your application can expose these pins to faults beyond the datasheet limits. The internal clamps should not be used to handle sustained overvoltage or negative-voltage conditions.

    The absolute maximum input clamp current of ±20 mA per pin and ±20 mA total across all inputs. there is a  ±2 mA limitation for continuous clamp current but we advise against continuous operation in this condition because VDDIO/VDDA may rise. 

    I recommend using a series current-limiting resistor with external low-forward-voltage Schottky clamps to the appropriate supply and ground—VDDIO/VSS for digital inputs and VDDA/VSSA for analog inputs. Select the diodes and resistor so the resulting pin voltage and current remain within specifications under the worst-case fault and temperature conditions. Use a divider or level translator when the normal signal voltage exceeds the supported input range.

    Best regards,

    Masoud