LMK1D2102L: single end input

Ryoma Ohashi

Part Number: LMK1D2102L

Tool/software:

Hi team,

For LMK1D2102L, when used as single and LVCMOS clock input, what value should the customer input for VTH when VDD=3.3V?
Will it be VTH=0.5*(VIH+VIL)=0.5*(0.7VDD+0.3VDD)=0.5*VDD=0.5*3.3=1.65V?

Regards
Ohashi

5 months ago

+1 vicente flores prado 5 months ago

TI__Mastermind 29542 points

Hello Ohashi,
You're correct, VTH will be 1.65V for a 3.3V LVCMOS signal.

Best regards,

Vicente

0 Ryoma Ohashi 5 months ago in reply to vicente flores prado

TI__Expert 5515 points

Hi team,

For 1.65V, my customer will make it from 3.3V by using voltage divider. In the electrical spec, it is said that IIH=50uA and IIL is 30uA for single end input. Since 3.3V/50uA=66kΩ, should the customer use a resistor that is less than 1/10 like 5.6kΩ for the voltage divider? Please let us know if there is a limitation or recommended values for the voltage divider for creating the VTH for single end input.

Regards
Ohashi

0 Ryoma Ohashi 4 months ago in reply to Ryoma Ohashi

TI__Expert 5515 points

Hi Vicente,

Any update on this?

Regards
Ohashi

0 Ryoma Ohashi 4 months ago in reply to Ryoma Ohashi

TI__Expert 5515 points

Hi team,

Please give us comment on this inquiry.

Regards
Ohashi

0 vicente flores prado 4 months ago in reply to Ryoma Ohashi

TI__Mastermind 29542 points

Hello Ryoma,
Sorry for delay, 1k resistors are fine.

Larger resistors value will consume less current, compared to say for example, 100Ohm resistors.

You can also follow the EVM user's guide for reference on single ended input config.

Best regards,

Vicente

0 Ryoma Ohashi 4 months ago in reply to vicente flores prado

TI__Expert 5515 points

Hi Vicente

vicente flores prado said:
You can also follow the EVM user's guide for reference on single ended input config.

I cannot find the EVM for I cannot find the EVM for LMK1D2102L. Could you provide as the snapshot for the single end input example design? Or let me know what value is typically used for single end input device.

Regards
Ohashi

+1 Michael Srinivasan 4 months ago in reply to Ryoma Ohashi

TI__Genius 11200 points

Hi Ryoma,

See the attached screenshots below.

Thanks,

Michael

Clock & timing

Clock & timing forum

LMK1D2102L: single end input