TS3DDR4000 unused pin

Luke Sun

Other Parts Discussed in Thread: TS3DDR4000

Hi Team,

If customer doens't use the whole TS3DDR4000's 12-bit pins (e.g, only A0-A9 are used), how to deal with thoses unused pins (both input pins & output pins)?

THank you!

over 9 years ago

0 Adam Torma over 9 years ago

TI__Mastermind 45575 points

Luke,

If customer doens't use all of the TS3DDR4000's 12-bit pins (e.g, only A0-A9 are used), we recommend you terminate both inputs and outputs with a 50 ohm resistor to ground. This will reduce unwanted signal reflections inside the device and preserve the TS3DDR4000 high performance.

Thank you,
Adam

0 Luke Sun over 9 years ago in reply to Adam Torma

TI__Intellectual 1830 points

Adam,
Thank you!

0 Luke Sun over 9 years ago in reply to Luke Sun

TI__Intellectual 1830 points

Adam,
Customer's board space is limited. Can they connect unused input pin together with a 50Ohm resistor and connect unused output pin together with another 50Ohm resisotr? Or even connect all unused input & output pin together with a 50Ohm resistor?
Thank you.

0 Adam Torma over 9 years ago in reply to Luke Sun

TI__Mastermind 45575 points

Luke,

Yes, you could tie all the unused pins to ground through a single 50 ohm resistor to save board space but for best performance each pin needs to have it's own termination to reduced reflections.

Adam

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TS3DDR4000 unused pin