TMUX7202: Issue on truth table

Hey Derun,

That is interesting. So you're saying that the logic looks to be the same on the TMUX7201 and 7202? 
Can you share waveforms? Just want to double check that they're seeing the same signal. Just a S/D with the logic input for both the TMUX7201 and 7202 would suffice.
Datasheet isn't wrong, they should be opposite logic and It's unlikely the device markings are wrong but it wouldn't be the craziest thing I've seen.

Thanks,
Rami

Sorry for my poor explanation earlier. I wanted to say that the control logic of TMUX7202 works like TMUX7201 while TMUX7201 works like TMUX7202.
When I follow Table 8-1 in the datahseet, what I understand from is:
For TMUX7202 if sel pin is low, the switch is closed and S=D.
For TMUX7201 if sel pin is high, the switch is closed and S=D.

Before I share waveform, let me explain my circuitry.
As it is attached, I have a current source which has connected 2 analog switches, one is TMUX7202 and the other is TMUX7201.
When none of switches are closed which means current source is floating, the voltage at measurement point shown in red in the waveform is 8.4V.

The yellow on the waveform represents SEL2 signal which controls TMUX7202.
When SEL2 signal is high, the switch is closed because the measurement point has 2V potential.
When SEL2 is low, the switch is open and current source is floating, so it is 8.4V.

The green on the other waveform shows SEL1 signal which controls TMUX7201.
When SEL2 signal is high, the switch is on because the measurement point has 8.4 potential. (floating)
When SEL2 is low, the switch is closed and the measurement point is shorted to source of the switch which is ground.

I hope it is clear. Because of the design, I have limited options to test swithces.

Thank you.
Kind regards.

Derun

Hey Derun,

Are you switching both sides at the same time? 
Can you try isolating one of the sides so they aren't shorted? Maybe just remove one device and test it. 
It does certainly look like the logic is backwards from these but I'm not certain how that could happen. 

As a side note, what is the implementation here in your system? Will you be toggling the 7201 and 7202 with the same control logic at the same time? It almost looks like you're creating a 2:1 switch, which the TMUX7219 may be a better option here.

Thanks,
Rami

Hi Rami,

Each switch has different control logic because I am using TMUX7202 for only test purposes. It will not be used in the product.

The design is made to drive low power laser diodes. TMUX7201 is there to enable/disable current source. 

I have ESD protection relays etc but this is out of scope.

If we go back to other question, I am not switching them at the same time.

While I toggle one of them, I make sure that the other one is always open.

Also when TMUX7202 is closed, I measured the current flowing through TMUX7202 and it was exactly same with the current source value.

So the other switch is open for sure. Otherwise, some current would flow through TMUX7201.

Thanks,

Kind regards,

Derun

Hey Derun,

Just wanted to update you on this. I'm looking into this further and looking to see if we have some data to confirm the behavior. At the same time, I've ordered some units of both parts to take a look myself as well. The units do take a few days to come in usually but fortunately the tests themselves should be pretty quick. I'll update you as I figure out whether we're looking at a possible datasheet typo, misprint or some other answer to explain what you're seeing.

If possible, can you send a couple pics of the top side of the devices?

Thanks,
Rami

Hi Rami,

Thanks for the effort. You can find the pictures below.

Device markings of TMUX7201 and TMUX7202 are H201 and H202 respectively.

Thanks.

Kind regards,

Derun

Thanks Derun,

I'll update you when the devices are in!

-Rami

Hi Rami, 

Is there any update on this issue?

Thank you.

Kind regards,

Derun