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USB EZ-PD™ Type-C Forum Discussions

KeTa_1341526
Level 5
Level 5
10 solutions authored 5 solutions authored 100 replies posted

Hello,

Use CCG2 with your Cable application.

It does not reset with XRES.

If you check the [Application Diagrams] in the data sheet, a 4.7kohm pullup is connected when XRES is not in use.

Is there no internal pullup in XRES?

If it exists, will it become a parallel resistor and weaken if 4.7kohm is connected?

Please tell me the correct connection method.

Best regards,

Takahashi

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Sananya_14
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hi Takahashi-san,

Yes, the XRES pin is pulled high internally. 4.7k is our characterized value for external pull up on the XRES pin and will not weaken the overall resistance such that the device goes into reset. Please refer to the App Note for more details- https://www.cypress.com/file/151561/download

Best Regards,
Sananya

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Sananya_14
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hi Takahashi-san,

Yes, the XRES pin is pulled high internally. 4.7k is our characterized value for external pull up on the XRES pin and will not weaken the overall resistance such that the device goes into reset. Please refer to the App Note for more details- https://www.cypress.com/file/151561/download

Best Regards,
Sananya

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Hi Sananya-san,

Thank you for your reply.

Can XRES be directly connected to VDDIO without the pull-up resistor?

Best regards

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Hi Takahashi-san,

We recommend using a pull-up resistor to connect XRES to VDDIO and hence the datasheet application diagrams also include 4.7k pull-up on the pin.

Best Regards,
Sananya

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Hi Sananya-san,

If VDDIO is directly connected, a large current will flow in and the current consumption will increase.

To prevent that, it's not directly connected to VDDIO (connected pullup:4.7kohm), right?

The value of the internal resistance of XRES is RPULLUP (8.5kohm to 3.5kohm), so if you connect a 4.7kohm pullup resistor to the outside, it is predicted that it will be about 2kohm to 3kohm.

Is the above recognition all right?

Best regards

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Hi Sananya-san,

> If VDDIO is directly connected, a large current will flow in and the current consumption will increase.

Another reason is that it is easily affected by power supply noise, isn't it?

Best regards

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Hi Takahashi-san,

Yes, your understanding is correct. However, I would have to check internally regarding the exact Rpullup range for XRES pin, although I think it should be similar to that for other GPIOs.

We also recommend connecting a decoupling capacitor of 0.1uF on the pin to avoid supply noise.

Best Regards,
Sananya

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