TFP410 RTFADJ resistor value

Joey Grasty

Other Parts Discussed in Thread: TFP410

Hello, team:

Raytheon asks:

TFP410 has RTFADJ resistor. Maximum ratings list this as 300 ohm to open circuit. Recommended value is 510 +/- 1%(non standard resistor). Is there any documentation indicating the results of changing this value? The 510 value seems to be the required resistor but text indicates this has a range that could be used. Using a 511 1% resistor will put us slightly higher and lower than your min/max values at the corner cases. Need documentation showing this will not be an issue.

Thanks for your help.

Regards,

Joey Grasty
AFA
Dallas FSO

over 15 years ago

0 Undrea Fields over 15 years ago

TI__Genius 11340 points

TFADJ resistance value adjusts the voltage swing of the TMDS outputs. The 510 ohm value produces a single-ended voltage swing of ~500mV (Upper limit specification is 600mV single-ended). The value is adjustable to allow for driving slightly longer, or shorter cables. I would not expect to see any noticeable difference in using a value of 510 or 511 ohms. The recommended values are 505 Ohm min, 515 ohm max.

0 Joey Grasty over 15 years ago in reply to Undrea Fields

TI__Expert 4490 points

Hello, Undrea:

Is there a curve or equation showing Rtfadj vs Voltage swing?

Regards,

Joey

0 Undrea Fields over 15 years ago in reply to Joey Grasty

TI__Genius 11340 points

I've searched through the bench characterization data that was taken on this device and cannot find these measurements. I assume it was taken on ATE, I have also not been able to find this parameter in the files I have found.

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TFP410 RTFADJ resistor value