DS90UB947-Q1: How to hundle unused pins

Tomoaki Yoshida91

Genius 5255 points

Part Number: DS90UB947-Q1

Hi Team,

Please tell me how to hundle unused pins.

We don't use D4 to D7 and I2S_xx.

I think that it is good to pull down to gnd because they are input pin.

Is there a recommended pull-down resister value for each terminal?

Best regards,

Tomoaki Yoshida

over 7 years ago

0 Davor Glisic over 7 years ago

TI__Expert 8165 points

Hello-

The D4-D7 inputs are LVDS receiver inputs and may be left open. The I2S_xx pins may also be left floating, if not used.

Regards,
Davor

0 Tomoaki Yoshida91 over 7 years ago in reply to Davor Glisic

Genius 5255 points

Hi Davor-san,

Thank you for your support.

I think that pulling the unused input pin to gnd or vdd is better than floating.
Is it mistake?

We are thinking about pulling down with about 10k to 50kΩ, but are there any problems?

Best regards,
Tomoaki Yoshida

0 Davor Glisic over 7 years ago in reply to Tomoaki Yoshida91

TI__Expert 8165 points

Hello-

Pull-downs on the LVDS differential inputs are not recommended. If both IN+ and IN- are pulled down to the same potential, the input state would be undetermined.

The GPIO/I2S pins have 25-kohm internal pull-downs when configured as inputs; therefore, there is no need for external pull-downs.

Regards,
Davor

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DS90UB947-Q1: How to hundle unused pins