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AIROC™ Wi-Fi and Wi-Fi Bluetooth Combos Forum Discussions

Yanyan
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Hi

I'm using the CYW43907 in a custom board. 

The MCU is powered from a buck that converts to 3.6V.

But for the VDDIO, I want voltage of 3.3V, because the MCU communicates with components with logic of 3.3V.

I don't want to add an external LDO, so I want to use the internal LDO (LDO3P3). My question is can I use LDO3P3 to power VDDIO, or do I have to use an external source.

 

Thanks

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Vivek_gunapati
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Hi Yanyan,

Please find the feedback below

1. The design need to consider how much DC the VDDIO needs to supply. If the design connects too many I/O pins, then the internal vout_3p3 may not be enough to source DC current, it would make it be dropped too much.
2. It may introduce I/O noise from other I/O pins if the design connects vout_3p3 to supply other I/O pins.

 

Regards

Vivek.

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Vivek_gunapati
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Hi ,

From the description we understand that you would like to use the CYW43907's internal LDO to source the VDDIO. From the datasheet  https://www.cypress.com/file/298236/download#page=33 we see the Pin 118 is an LDO out pin. 

Currently we are checking with the internal team if we could use the 118 Vout_3p3 to source the other VDDIO pins in LDO3P3 internal LDO mode. 

 

Regards

Vivek.

Vivek_gunapati
Moderator
Moderator
Moderator
5 likes given 250 sign-ins 10 likes received

Hi Yanyan,

Please find the feedback below

1. The design need to consider how much DC the VDDIO needs to supply. If the design connects too many I/O pins, then the internal vout_3p3 may not be enough to source DC current, it would make it be dropped too much.
2. It may introduce I/O noise from other I/O pins if the design connects vout_3p3 to supply other I/O pins.

 

Regards

Vivek.

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