TMDS181: Internal Threshold for OE Pin When Using Capacitor

Hi Francisco-san,

Thank you for your prompt reply.

I am looking forward to hearing the detailed information from you ASAP.

Best regards,
Kato

Hi Francisco-san,

Thank you for your response.

Could you please tell me the value of the internal pull-up resistor on the OE pin ?

Best regards,
Kato

Hi Francisco-san,

Sorry for overlooking that content which you mentioned above.
I understood and will contact you if I get additional questions from our customer.

Best regards,
Kato

Hi Francisco-san,

Unfortunately, I got an additional question from our customer.

He has used the probe with the high impedance (the order of MΩ), so he doesn't think that the OE terminal voltage drops less than 2.50V.
If it drops to 2.5V at VCC=3.3V, it means that 625kΩ resistor is connected between the OE pin and GND.
Could you please give me your advice again as he was confused ?

Best regards,
Kato

Hi Francisco-san,

Thank you for your prompt reply.

I will look into customer evaluation condition again and will get back to you.

Best regards,
Kato

Hi Francisco-san,

Our customer measured the OE pin voltage again by using the digital multimeter with the input impedance of 10MΩ.
Unfortunately, that voltage was approximately 2.5V.
So, could you please double-check the OE pin voltage using TMDS181RGZEVM as well ?

Best regards,
Kato

Hi Francisco-san,

I also measured the OE pin voltage using TMDS181RGZEVM with the digital multimeter AD7451A, which was approximately 2.34V at VCC = 3.27V.
In addtion, the impedance between the VCC and the OE pin was 188kΩ and the impedance between the OE pin and GND was 195kΩ during the power-off.
So, could you please tell me that reason why that voltage drops in detail ?

Best regards,
Kato

Hi Francisco-san,

Of course, I removed the R77 resistor and added the 0.22uF capacitor to C26 when measuring the OE pin voltage, the measured voltage is same even if removing the C26 capacitor.
Then, I removed the R77 and C26 when measuring the impedance between the OE pin and VCC/GND during the power-off.
I think that you could understand this symptom by doing the same measurement.

So, could you please tell me that reason why that voltage drops in detail as soon as possible ?

Best regards,
Kato

Hello Kato-san,

I think could be possible that the input impedance (from OE to GND) is affected when the device turn on and you connect the Voltmeter. With the values that you are reporting, looks like this impedance change to 473k. I think the impedance from OE to Vcc is correct. Let me confirm this one with the design team.

Regards

Francisco

Hi Francisco-san,

Thank you for your reply.

I am looking forward to getting the detailed information from your design team as soon as possible.

Best regards,
Kato

Hi Francisco-san,

Could you please let me know if you have any updates ?

Best regards,
Kato

Hi Francisco-san,

Thank you for reporting the current status.
I am looking forward to getting the detailed information from you.

Best regards,
Kato

Hi Francisco-san,

Thank you for your information.

I have one more request, so could you please tell me the internal threshold for OE pin ?

Best regards,
Kato

Hi Francisco-san,

Thank you for your explanation.

Is the threshold voltage of the OE pin non-disclosure ?
Please tell me the threshold voltage if possible.

Best regards,
Kato

Hi Francisco-san,

I would like to know the internal threshold voltage when connecting the capacitor between the OE pin and GND.

Best regards,
Kato

Hi Francisco-san,

Thank you for your quick response.

We will persuade our customers with that information from you.
I greatly appreciate your cooperation.

Best regards,
Kato