DP83848J: device gets damaged repeatedly under normal operation

Stani Bell Ngoufack Tchoufack89

Intellectual 1970 points

Part Number: DP83848J
Other Parts Discussed in Thread: DP83822I

Hello,

a customer of mine is currently using the DP83848JSQ in a design; however the device repeatedly gets damaged in the application. What they have been able to notice is that PIN 28 (REF_CLK Eingang) gets damaged (on the hardware) and they also see some shorts between VCC and GND.

contrary to what is written in the datasheet (see image below), they have a 4.7kOhm pull-up resistor in MODE Select. The device is supposed to be used in RMII mode:

do they see this problem due to the undefined state on the input of the MODE select?
can this cause the device to switch into the MII Mode?
must one use a 2.2KOhm pull-up as mentioned in the datasheet or is it also ok to use the 4.7KOhm as it is the case here?
for a new design the customer plans to use the DP83822i also with a 4.7KOhm pull-up resistor. Are they going to see the same issue here

thanks for your support.

Regards,

Stani

over 4 years ago

Aniruddha Khadye over 4 years ago

TI__Mastermind 18425 points

Hi Stani,

I would recommend following that datasheet values. It is difficult to characterize the IC for values outside of the datasheet. The PHY might be entering a non-deterministic mode. However, its difficult to say if this can cause damage to the part or not. Can you ask customer to change the strap resistor values to match the datasheet values and check again.

-Regards

Aniruddha

Stani Bell Ngoufack Tchoufack89 over 4 years ago in reply to Aniruddha Khadye

TI__Intellectual 1970 points

Hi Aniruddha,

thanks for your response. i've let the customer know and they will try the 2.2kOhm as recommended in the datasheet.

Regards,

Stani

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DP83848J: device gets damaged repeatedly under normal operation