DS90UB928Q-Q1: Pin settings

Youhei Miyaoka

Expert 3935 points

Part Number: DS90UB928Q-Q1

Tool/software:

Hi expert,

My customer have question for below pin settings, they are not familiar with FPD-link, could you support this query?

#1 Not used pin setting

They do not use below pin. Is these floating OK? or any other termination required?

#2 When IDx=L, is it OK to connect GND directly?

#3 Internal pull-down resistance

Could you teach me internal resistance at "I/O LVCMOS with internal pull-down" pin? Approximate value is OK.

Regards,

Youhei MIYAOKA

3 months ago

+1 Hamzeh Jaradat 3 months ago

TI__Guru** 107540 points

Hello Youhei,

Youhei Miyaoka said:
#1 Not used pin setting

All these pins have internal pull-down resistor when they are configured as inputs. However, these pins are set to output by default, hence a PD is safer.

Youhei Miyaoka said:
#2 When IDx=L, is it OK to connect GND directly?

It is recommended to ground via PD resistor to prevent leakage current.

Youhei Miyaoka said:
#3 Internal pull-down resistance

Internal PD resistors are approx. 25Kohm

0 Youhei Miyaoka 3 months ago in reply to Hamzeh Jaradat

TI__Expert 3935 points

Hi Hamzeh,

May I confirm again about MCLK pin? This pin is not shared with any other pins. Is this pin also have internal pull-down?

Regards,

Youhei

0 Hamzeh Jaradat 2 months ago in reply to Youhei Miyaoka

TI__Guru** 107540 points

Hello Youhei,

You are right. This pin does not have internal pull-down, hence an external pull-down is needed if left floating. a 10kohmresistor is fine.

0 Youhei Miyaoka 2 months ago in reply to Hamzeh Jaradat

TI__Expert 3935 points

Hi Hamzeh,

Thank you! I received additional question for lock pin.

When the operation of the lock pin goes low when an abnormality occurs, which of the following processes occurs?

- Continue low until the fault clears
- After a certain period of time, it becomes high, and if it is not released, it becomes low again
in the latter case, please tell us about the duration of the low.

0 Hamzeh Jaradat 2 months ago in reply to Youhei Miyaoka

TI__Guru** 107540 points

Hi Youhei,

If anything wrong with the link, the LOCK pin will go low and stays low until the fault is cleared then it will go high.

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DS90UB928Q-Q1: Pin settings