CDCLVP1204: 3.3V LVCMOS input

Expert 1760 points

Part Number: CDCLVP1204
Other Parts Discussed in Thread: CDCLVD1208

Hello,

Please advise on how a 3.3V clock input can be fed to the device.

Thanks,

over 4 years ago

0 Jennifer Bernal over 4 years ago

TI__Genius 16845 points

[Part in Question: CDCLVP1204]

Hi,

A 3.3V clock input can be fed if your VCC is 3.3V.

Regards,

Jennifer

0 SM over 4 years ago in reply to Jennifer Bernal

Expert 1760 points

Hello Jennifer,

The device power supply is 2.5V and Pg 12 of the datasheet of CDCLVD1208/04 says the following:

Figure 15 illustrates how to couple a 2.5-V LVCMOS clock input to the CDCLVD1208 directly. The series resistance, RS, must be placed close to the LVCMOS driver if required. 3.3-V LVCMOS clock input swing must be limited to VIH ≤ VCC.

May I ask you to please help us clear the doubt.

Thanks,

0 Jennifer Bernal over 4 years ago in reply to SM

TI__Genius 16845 points

[Part in question: CDCLVD1208]

Hi SM,

Using a 3.3V LVCMOS clock input would require the signal to be attenuated by a resistor divider to meet datasheet specifications.

See this e2e post for further explanation on how to add a 3.3V LVCMOS.

Regards,

Jennifer

0 SM over 4 years ago in reply to Jennifer Bernal

Expert 1760 points

Hello Jennifer,

Thank you for the reply. Based on the forum post you referred, this is the circuit we understand should work. May I ask you to please confirm the same.

Thank you for your help,

0 Jennifer Bernal over 4 years ago in reply to SM

TI__Genius 16845 points

[Part in question: CDCLVD1208]

Hi SM,

That circuit should work. You can test your design with our IBIS model under Design Tools & Simulation.

Also, please keep threads to one topic/part for clarity. For future questions, make another e2e post.

Regards,

Jennifer

Clock & timing

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CDCLVP1204: 3.3V LVCMOS input