TMUXHS4212: How to escape test mode?

Hi Baw;

    Power on  and off will definitely exit test mode.

   I believe OEn L-H-L will exit test mode too, but I need to confirm in the lab.

Best

Brian  

thank you for your prompt response, looking forward to your experimental results~
Is there any control flow to avoid entering test mode?

Thank you~~

Hi Baw:

   I can't make it into test mode in our lab. But I will check with our designer to confirm.

Best

Brian

Hi Brian,

Do you get any feedback from your designer?

I have another questions and need your advice.
In our design the RESVD* is floating, when we set VCC to 3.3V and VCM is 0V the TMUXHS4212 works fine. However, when we change VCC to 1.8V, some TMUXHS4212 will not work under the same test conditions with VCC 3.3V. The failure rate is about 40%.

Will it enter test mode only when VDD 1.8V condition?  

Is there any way to make operate normally when VCC is 1.8V in the RESVD* floating condition?

Thank you~~

Hi Baw:

   I was told by designer they need time to setup the simulation and will start by 8/19.

   In your application, did  SEL toggle? If not, then MUX will not enter test mode.

Best

Brian

Hi Brian,
Yes, we have toggle SEL several times. But the strange thing is that we used the same test conditions and only changed 3.3V and 1.8V, but it seems that only 1.8V will cause problems. Is there any direction I can go to confirm?

I searched for previous discussions and it was mentioned that SEL will enter test mode after toggle13 or 16 times. Do you have the exact number of SET toggles times before entering test mode?
Also, if RESVD* is floating, is there only a risk of entering test mode? or other problems will arise?

Thank you~

Hi Baw;

    I believe we simulate with 3.3v and  SEL toggle 16 times  to enter  test mode before.

   other than  test mode,  we didnt see other  issue  or  problem arised.

   But I will  ask design to simulate again with 1.8v as well in next few days.

Best

Brian

Hi Brian,

Thanks for your feedback.

Since we have some faulty switches, can we send them back to TI for failure analysis?

Do you mean those  failures at 1.8v?  Is it possible  to pull RSVD pin to high and test again before you send to us?

Best

Brian

Hi Brian,

Yes, under the same test conditions, some switches will work abnormally when we use 1.8V VCC.

I checked internally, even if we short RSVD* to VCC, when VCC is 1.8V, the same phenomenon still occurs.

Hi  Baw:

    What is your test condition? So I can ask design to simulate with same  condition.

  Also what customer for this project ? Can you  use 3.3v  for production?

Best

Brian

Hi Brian,

Sorry, we are unable to provide customer information due to NDA restrictions. After confirming with our customer, their test condition as below.

1. Switch power on -> SEL:L -> test pattern transmission -> SEL:H -> test pattern transmission -> SEL:L -> test pattern transmission -> Power off. 

2. Different test patterns correspond to different test frequencies, and the switch are random fail in different frequency.

The test conditions are the same whether using 1.8V or 3.3V, but only 1.8V will cause problems.

Our customer need to use 1.8V for production, so hope we can figure out the problem.

Could you provide a contact window for sending the switch back to TI? or where can I find relevant information?

Thank you~

Hi Baw:

   For 1.8v supply, signal common mode should below 1.2v. Can you check with customer ?

  To return unit to TI, you need to contact local TI CQE, which country you are at?

Best

Brian

Hi Brian,

I confirmed with our customer the Vcm is 0V. We are in Taiwan, please help provide the CQE information.

Thank you.

Ok, let me check and get back to you tomorrow.

Best

Brian

Hi Brian,

Great, thank you~