SN74CBTLV3257: Circuit Connection Implementation Clarification

Sandhiya Subashree M

Intellectual 320 points

Part Number: SN74CBTLV3257
Other Parts Discussed in Thread: TMUX1574

Tool/software:

Dear TE Team,

We are using the part number SN74CBTLV3257.

We are planning to connect bidirectional signals (Data Rate : 104 MB/S) .In our case, pin 4B1 is not connected (NC), but pin 4B2 is connected.
Can we proceed with this configuration? Will leaving 4B1 unconnected affect the functionality of 4B2?
We are planning to route a clock signal with a frequency of 208 MHz through this multiplexer/demultiplexer IC.

Please confirm whether the SN74CBTLV3257 can support this frequency.

1 month ago

0 Kameron Hill 1 month ago

TI__Mastermind 24440 points

Hi,

1. Leaving a io pin of a multiplexer is fine but however it is best practice in high speed applications to tie the unused io pin to ground through a 50 ohm termination resistor. Here is a FAQ our team has about this topic.

2.The SN74CBTLV3257 is not a good choice to pass a 208 MHz signal through.( This is because its bandwidth is only 200MHz and you will see significant signal attenuation if you try to pass 208Mhz through the device.) https://e2e.ti.com/support/switches-multiplexers-group/switches-multiplexers/f/switches-multiplexers-forum/1025430/faq-how-do-i-select-the-right-analog-switch-multiplexer-bandwidth-based-on-the-data-rate-of-my-protocol

A better choice would be to use a p2p drop in upgrade device called the TMUX1574. This device has a 2Ghz bandwidth and should be more than enough bandwidth for your application.

The correct choice for this application is to use the TMUX1574 but please let me know if you have any additional questions.

Regards,

Kameron

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SN74CBTLV3257: Circuit Connection Implementation Clarification