CC2640R2F: Maximum Current over Clamping Diodes

Andre Vaas

Part Number: CC2640R2F

Hello,

we have in our circuit 2 power domains. One is on 3.3 V (communication partner) and another (CC2640R2F) is on 3.3 V to 1.9 V. The two domains communicate over UART. If the power domain with the CC2640R2F drops down to 3.0 and lower voltages we overdrive the maximum difference per GPIO of 0.3 V. This is related on the clamping diodes, right?

Question: We could add a series resistor on the UART RX Path to avoid exceeding the maximum current over the UART RX GPIO clamping diode. Whats the maximum current over the GPIO clamping diodes?

Thank you!

Regards
Andre

over 7 years ago

0 TER over 7 years ago

TI__Guru**** 317180 points

Have you considered 6.11 in www.ti.com/.../cc2640r2f.pdf as a solution?

The maximum ratings in the datasheet has to be followed, a resistor to limit the current will not change this.

0 Andre Vaas over 7 years ago in reply to TER

Intellectual 570 points

Thanks for the clue. But in our system, we do not have any pin on our connector remaining, to supply a separate VDDS2 domain with 3.3 V.

Could you please check internally, whats the maximum current over the clamping diodes?

0 TER over 7 years ago in reply to Andre Vaas

TI__Guru**** 317180 points

Some MCUs are designed in a way that the ESD diodes in the pad can be used to handle a signal voltage difference. But for CC13xx this is not the case. The absolute maximum ratings in the datasheet are valid regardless of the current flowing in the ESD diodes. You can therefore risk to damage the chip over time regardless of how much current that flows in the ESD diodes.

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CC2640R2F: Maximum Current over Clamping Diodes