LMK1D1208: Recommended unused LVDS input termination

Kazuhiko Hirano

Part Number: LMK1D1208
Other Parts Discussed in Thread: CDCLVD1208,

Hello,

My customer would like to use either LMK1D1208 or CDCLVD1208.
They plans to use it as 1 (IN1_P/IN1_N at LMK1D1208, INP1/INN1 at CDCLVD1208) to 8 LVDS in/out buffer.
They would also like to use IN_SEL pin as EN pin (High = enable) and make 8 output LVDS low when IN_SEL pin = Low.
In order to do this, how they should terminate unused LVDS input (IN0_P/IN0_N at LMK1D1208, INP0/INN0 at CDCLVD1208)?

Best regards,

K.Hirano

over 3 years ago

0 Jennifer Bernal over 3 years ago

TI__Genius 11695 points

Hi Hirano,

You may use answer to #1 from this previous e2e post on how to terminate unused inputs. The customer may choose to leave the unused input floating or ground them with 1k-ohm resistors.

Regards,

Jennifer

0 Kazuhiko Hirano over 3 years ago in reply to Jennifer Bernal

TI__Genius 13278 points

Jennifer,

Thank you for your response.
Let me confirm some more.

When unused INP0/INN0 are left float or connected to GND with 1k-ohm resisters and IN_SEL is low at CDCLVD1208, what would the 8 output be, LVDS low, LVDS high or something else?

The recommended unused terminations for CDCLVD1208 also apply to LMK1D1208?

Best regards,

K.Hirano

+1 Jennifer Bernal over 3 years ago in reply to Kazuhiko Hirano

TI__Genius 11695 points

Hi Hirano,

The unused input terminations apply to both CDCLVD1208 (datasheet page 10, 12) and LMK1D1208 (datasheet page 13, 14). Both can be expected to be logic low when IN_SEL chooses the unused input.

Regards,

Jennifer

0 Kazuhiko Hirano over 3 years ago in reply to Jennifer Bernal

TI__Genius 13278 points

Jennifer,

Thank you for your confirmation!

Best regards,

K.Hirano

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LMK1D1208: Recommended unused LVDS input termination