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TS3A4751 / Spectrum of Capacitance ,leakage current and Supply current

Guru 20090 points
Other Parts Discussed in Thread: TS3A4751
Hello E2E team,

I want to know below information for using TS3A4751.
If you can't open these information, please kindly let me know it.

1.Spectrum of Capacitance 
Spectrum and variation in lot  of "CNO(OFF)/CCOM(OFF)/CCOM(ON)

2.Spectrum of leakage current
Spectrum and variation in lot  of "NO OFF leackage current / COM OFF leakage current / COM ON leakage current.
 
3.Relativity of Supply current and VI
In my understanding there is relativity between Supply current and VI.
So I would like to know supply current in our condition.
Our condition is as below.
 
V+:3V
VI:1.8V
For I/F using.
 
Best Regards,
Ryuji Asaka
  • Hello again,

    I post more information.
    Customer use 40pcs of TS3A4751 as chain.
    One of the TS3A4751 has minimum capacitance and leakage current.
    but if we use 40pcs that has big difference between Min and Max.
    So , I would like to know distoribution.
    Then calculate total capacitance and leakage current an supply current. 
     
     
    Concerning Supply current, when VI=0V and V=V+ supply current is minmmum in my understanding.
    And supply current will be max when VI became half of V+.
    If my understanding is incorrect please let me know.
     
     
    Best Regards,
    Ryuji Asaka 
  • Hi Ryuji,

    I am looking into this and will have an answer for you shortly for the capacitance.

    For leakage current, these min/max values are already provided in the datasheet.

     

  • Hi David,
     
    Thank you.
    I wait answer.
     
    For Leakage current,  there are big diffrence bitween "40 x min" and  "40 x max".
    Please see the below picture as my image.
    Customer need like this information .
     
    And how about supply current (Positive-supply current "data sheet P3") ?
    There is max value of 0.75uA (Full temp) under the condition of " V+=3.6V and VIN=0 or V+".
    Is this condition of max of supply current ?
    If VIN =1.8V , will be supply current decreased from above condition's value ?
     
     
     
    Best Regards,
    Ryuji Asaka
  • Hello Ryuji,

    I will be taking over this for David as he has urgent matters to attend to.  Please my answers below:

    1.  This is still being looked into.  

    2.  The leakage currents are specified in the datasheet as described above.  Customer can expect no more leakage than the max value across temp and process.  Are these values not acceptable to the customer?  Why does the customer need this data?

    3.  Supply current has no dependency on the input voltage to the switches.  regardless of if there is 1 V 2 V etc on the switches the same voltage is applied to gate of the switch to turn it on. 

    Regards,

    Andrew

  • Hello Andrew,
     
    Thank you for the information.
    I got informaion of input capacitance and supply current.
    And sorry for late reply and my infuccient explanation for leakage current.
     
    I'm checking further background...
    And I will post  again tomorrow.
     
    Best Regards,
    Ryuji Asaka
     
     
     
  • Hello Andrew,

    I'm waiting customer's reply.
    I post again after get the reply.
     
    Best Regards,
    Ryuji Asaka
  • Hello Andrew,
     
    Sorry for the late reply. 
    Please see the attached pdf file and below as diagram and detail of background.
    If there are any questions please let me know.
     
     
    -------------------------------
    Customer's request Dead Line:
    8th/Jan/2013
     
    Circuit description:
    Customer measures DUT off Leakage current by this circuit.
    1 of the “DUT-Current Measurement Unit” line is turned on when measuring
    DUT off leakage current. Other lines are turned off.
    If total Leakage Current is over 110nA , current measurement accuracy will be Low.
     
    When total lekage current is over 110nA, they can separate circuit.
     
    Request Data:
    Customer' request is 3σ of below Leakage current parameter at over 10 lot.
    Data Condition, Ta=85℃,  V+=3.6V
        -No off leakage current
        -COM off leakage current
        -COM on leakage current
     
    Target spec :
     Analog Switch TOTAL Leakage Current≦110nA/1 current measurement unit
     TOTAL Leakage current =1 * Ino(off) + 41 * Icom(off) + 1 * Icom(on)
       If 3σ=2nA, customer’s calculation is as below (for example).
       1*2nA(Icom(on))+1*18nA(Icom(off)max)+40*2nA(Icom(off))+1*2nA(Icom(on))=102nA
     
    Others:
    I got comment  which customer  want to use TS3A4751 as possible.
    We explained that we can’t guarantee request data. And customer accepted it.
    -------------------------------
     
    Best Regards,
    Ryuji Asaka
  • Hello Andrew,
     
    Complement about request data.
     
    I posted that request data is distribution.
    But I confirmed 3σ value is ok as customer's request data.
    Then, customer can estimate total leakage current.
     
    For example,
        -No off leakage current   : 3σ =2nA
        -COM off leakage current   : 3σ =2nA
        -COM on leakage current   : 3σ =2nA
     
    Best Regards,
    Ryuji Asaka
  • Hello Ryuji,

    I have checked char data and it correlates with the datasheet for the leakage values specified.  Customer should plan on worst case leakage currents specified in datasheet as it is very possible to get parts that have near the max leakage.

    This data is taken across temperature and corners.

    Regards,

    Andrew

  • Hello Andrew,
     
    Thank you for checking the char data.
    I will check about handling of this issue.
    And if need, I will post again.
     
    Best Regards,
    Ryuji Asaka
     
     
  • Hello Andrew,
     
    I got new information from customer about design of TS3A4751.
    Could you please kindly consider to provide 3σ data of leakage current ?
    Attached file is image of the dividing circuit for reduce the total leakage current.
     
     
    1. There is no competitor of TS3A4751.
        Competitor don't have switch of 4ch/2mm sq size.
        So, they already started design by using TS3A4751.
     
    2.If customer consider leakage current as 18nA for all devices, they must divide circuit.
      Please see the attached file Page 1.
      In this case, they need more "8 control signal" for On/Off control of switch from "FPGA".
      But, they don't have margin of FPGA pin assign currently.
     
    3.If we can provide 3σ data as lower than 18nA, they can reduce control signal.
      Please see the attached file Page 2.
      In this case, 3σ is 10nA.
      Customer can reduce dividing number.
      Thus, customer can reduce control signal from FPGA.
     
    4.When we can provide 3σ data and customer will design circuit by that data, there is out of device from 3σ.
      Customer has counter plan.
      They will take screaning themselves.

    5.Could you please kindly consider to provide 3σ data of leakage current ?
       If there are any requirement for providing the data , please let me know.
     
    *dividing number of attachment is image.
      I would like to  tell that we will provide 3σ data, customer can reduce pin assign of FPGA.
     
    Best Regards,
    Ryuji Asaka
  • Andrew san,
     
    Sorry for bothering you.
     
    I understan'd that we should use leakage current as datasheet data due to there is max  data.
    But , Are there any possibility of getting leakage current distribution data to me?
     
    - If no, please kinldy let me know the reason ?
      Then I will explain to our customer.
     
    - If yes, please kindly let me know the condition for getting data.
      Then, I will get the data for getting distribution data.
     
    Best Regards,
    Ryuji Asaka
  • Hello Ryuji-san,

    I apologize for the delay in response to this.  I have looked into the char data and discussed with the team on how this data is taken.  There is no distribution data taken for this parameter.  It is measured across temp and process to find a maximum value.  A "buffer zone" is then added to these values to ensure no units reach the customer outside of datasheet values.

    Regards,

    Andrew

  • Hello Andrew san,
     
    Thank you for the information.
    I understood the situation of this parameter.
    I will explain it to customer.
     
     
    Best Regards,
    Ryuji Asaka
     
     
  • Hello Andrew san,
     
    Sorry again.
    Can I have the leakage current  value of  "buffer zone"  ?
     
    Best Regards,
    Ryuji Asaka
  • Hello Ryuji-san,

    TI will only guarantee that parts be within lmiits specified in the datasheet.  The buffer zone is ~2-3 nA.

    Regards,

    Andrew

  • Hello Andrew san,
     
    Thank you very much!
    I undeerstand that we can only garantee data of datasheet.
    This data is used for refference.
     
    Best  Regards,
    Ryuji Asaka