TMUX1308A-Q1: Package of TMUX1308A-Q1 and it's output capacitance

Hi Alex.

About this I have two questions.

1, I want to know the capacitance of Con and output capacitance to GND. because I want to know it have any difference to TMUX1308-Q1. 

2, When I use TMUX1308-Q1 and TMUX1309-Q1, I found when I use different mux, output performance it different, when I use 8 channel to 1 CH, the output pulse wide than I use 4 to 1 channel TMUX1309-Q1. So I want to know the difference of this two mux? I think the output capacitor of 8 channels may bigger.

Thanks and Regards

Guangfei Xia

Hi Alex.

Another question. Not about mux. about high speed OPA.

I want to know the OPA output jitter. which will influence this?

We found our new design use opa855+ths4541 the jitter higher than before?

Thanks and Regards

Guangfei Xia

Hi Guangfei,

The difference in channel configuration can lead to a difference in capacitance. The 8:1 can exhibit higher capacitance than the 4:1 which would lead to the wider pulse width that you mentioned. We do not spec output capacitance specifically. We have Con and Coff spec'd which should provide all the info needed. The output capacitance in an off state is Cdoff in this case. In an on state, the source and drain capacitance is the same. 

Unfortunately I can not provide insight into the OPA question as this is outside my expertise. I can move this thread to their group if that works for you!

Regards,

Alex

Hi Alex,

Could you supply some data or test result, how large output capacitor will change cause by 4 to 1 change to 8 to 1. In datasheet Cdoff are same, can't find any difference.

About the OPA please help move this to other group.

I went ahead and followed up offline regarding the capacitance since this is more internal data. I'll move this thread to OPA team now. 

Regards,

Alex

Hi,

Could you please share exactly what you are seeing with the OPA855+THS4541 combination. An image of this irregular behavior would be helpful in understanding what might be happening. Could you also share a schematic of the circuit in question.

Best Regards,

Ignacio

Hello Alex,

Here are more questions from the customer.

This test result meets our test result in lidar. But if only 3pf difference between 8 channels to 4 channels. can’t influence my test result so much. When I add this 3pf capacitor to simulation circuit. Can only have about 5% pulse width change, but in detail board test result, at least 30% pulse width change. Do you know any other difference between 1308 to 1309?

 Could you help check the Rdson, does it have any difference?

 Another question, how do you test CDOFF, because always have one channel input connect output. Through EN pin?

 They also found in their test result, S0 and S2 pulse is much narrow compare to other channel, please help check why this happened? Does those two channels have any different?

Best regards,

Wenting

Hi Wenting,

The thread got assigned to the op amps team as part of your previous question regarding our devices. If this question is directed towards the MUX team it would probably be easier to create a new thread for specific questions for that device.

Best Regards,

Ignacio