DP83848K: Question about DP83848K circuit (termination, short distance, impedance)

Satoshi

Guru 19655 points

Part Number: DP83848K

Please let me know about three points below for DP83848K.

①About datasheet page-65(Figure 7-2), is resistor value required 49.9Ω only?

　If in the condition of RJ-45 side, is resistor value change to 47Ω, no problem?

②Is there information for impedance control?

③If there performance data for "very" short distance transmission?

　For example, ~50cm distance.

Best regards,

Satoshi

over 8 years ago

0 Satoshi over 8 years ago

Guru 19655 points

Any update on this?

0 Rob Rodrigues over 8 years ago in reply to Satoshi

TI__Mastermind 19780 points

Hi Satoshi-san,

1. 49.9 ohm, 1% resistors are required. 47 ohm is not acceptable. IEEE specification will not be met if 47 ohm is used.

2. Impedance control for which portion? The cable interface should be 100 differential, +/- 5%. The MII or RMII should be 50 ohm single ended, +/- 5%

3. What kind of performance data is required? Short connections (~50 cm) are OK with DP83848.

Best Regards,

Interface

Interface forum

DP83848K: Question about DP83848K circuit (termination, short distance, impedance)