Hello experts,
I want to connect a PWM output using open-drain pad configuration. The PWM bank voltage is 1.8V.
I couldn't find the information I need in the datasheet.
Can anyone answer :
1. In open-drain configuration, what is the maximum allowed external voltage on the pad?
2. What is the maximum allowed current through the internal transistor?
Regards,
Erez
Hi Erez
1. maximum allowed voltage on the pad is defined by
Datasheet Table 4. Absolute Maximum Ratings
Input/output voltage range : OVDD+0.3V (OVDD is the I/O supply voltage.)
2. maximum allowed current through the output transistor is not defined by
datasheet. Limitation would be max. Junction temperature defined in
Table 6. Operating Ranges
Note output transistor impedance may be affected by DSE, defined in
Table 33,34 GPIO Output Buffer Average Impedance
Best regards
igor
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Hi Igor,
Thanks for the prompt reply.
I saw the OVDD+0.3 spec in the Absolute Maximum Ratings table. However, I have doubt that it is correct for Open-Drain configuration. I think OVDD+0.3 is the limit for Totem-Pole configuration.
Open-Drain is used very frequently for simple level-shifting is slow signals. I need to upshift from 1.8V to 3.3V.
Any way to verify this with the h/w team?
Regards,
Erez
Hi Erez
yes this is correct. Note also there is esd protection
diode on pad.
Best regards
igor