SN65LVDS33: Layout Guidelines for maintaining 50ohms impedance on the out pins

Rajkumar Selvavinayagam

Prodigy 40 points

Part Number: SN65LVDS33

We have added external series resistor of 25ohms to the out pins(Y) of SN65LVDS33 for maintaining 50ohm impedance,

Do you have any Layout guidelines on placement of resistors

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 316690 points

Source termination resistors should be placed directly at the output pin.

0 Rajkumar Selvavinayagam over 2 years ago in reply to Clemens Ladisch

Prodigy 40 points

Termination resistor should be kept near the driver output pin or it can be little far away from driver output pin

0 Rajkumar Selvavinayagam over 2 years ago in reply to Clemens Ladisch

Prodigy 40 points

Could you please share any layout reference

+1 Clemens Ladisch over 2 years ago in reply to Rajkumar Selvavinayagam

Guru 316690 points

The trace between the driver output pin and the resistor is not properly terminated. For short lengths, this does not matter, but an increase in the length also increases the noise at signal edges. Place it as near the pin as possible.

0 Rajkumar Selvavinayagam over 2 years ago in reply to Clemens Ladisch

Prodigy 40 points

Thankyou

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SN65LVDS33: Layout Guidelines for maintaining 50ohms impedance on the out pins