SN75DP130: Vcc off operation

Takeshi Sasaki

Part Number: SN75DP130

Hi team,

Could you give me comment on if following phenomenon is reasonable or not? If not, please give me advise how to solve it?

Condition: System has 2 boards. One is the board of DisplayPort monitor, the other is the board that SN75DP130 is mounted.

Those 2 boards are connected with cable, and DisplayPort monitor board is powered ON, and SN75DP130 mounted board is powered OFF.

Question: For that condition, the customer has observed HPD_SRC output signal that is came from HPD signal (2.2V) at HPD_SNK input side. Is it correct/reasonable operation of SN75DP130? The customer concerns that HPD_SRC output signal may cause damage of FPGA connected to SRC.

Also, the customer has observed unidentified 1.1V at VCC pin when SN75DP130 is powered off at above condition. The customer is not sure if the unidentified VCC voltage can cause HPD_SRC output signal.

Best regards,

Takeshi Sasaki

over 5 years ago

0 David (ASIC) Liu over 5 years ago

TI__Guru**** 176511 points

Takeshi-san

If they remove the cable between the DP130 and the monitor, are they still seeing the voltage on HPD_SRC and the VCC?

Thanks

David

0 Takeshi Sasaki over 5 years ago in reply to David (ASIC) Liu

TI__Expert 4480 points

Hi David,

Thank you for your comment. No, when they remove the cable, the both of the voltages at HPD_SRC(2.2V) and VCC(1.1V) are disappeared.

Best regards,

Takeshi Sasaki

0 David (ASIC) Liu over 5 years ago in reply to Takeshi Sasaki

TI__Guru**** 176511 points

Takeshi-san

If the monitor is powered up, it will drive its HPD high, which is connected to the DP130 HPD_SNK. If the DP130 is off, the voltage on HPD_SNK may leak onto the DP130 HPD_SRC and VCC. If they disconnect HPD_SNK, are they still seeing the voltage on the HPD_SRC and VCC?

Thanks

David

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SN75DP130: Vcc off operation