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Original question:

DS90UB954-Q1: Do we have a recommended scheme for TVS protection device of DS90UB954-Q1?

DS90UB954-Q1: ESD Protection of Rin+/Rin- port

d_zero
Genius 4440 points
Part Number: DS90UB954-Q1
Other Parts Discussed in Thread: TPD4E02B04-Q1, TPD1E01B04-Q1

Hi Kenneth,

we are looking on how to do ESD protection of Rin+ and Rin- port when PoC is used.

Referring to https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1192674/ds90ub954-q1-do-we-have-a-recommended-scheme-for-tvs-protection-device-of-ds90ub954-q1/4496304#4496304

you stated that the ESD diode should be place between the connector and the AC coupling capacitor. But later you suggested to look at app note slvaf60a where the diode is used between the Rin input and the AC coupling capacitor which is other way around from your first suggestion, please can you explain.

My understand is if PoC is used then we probably won't find a ESD diode with low capacitance and high Vrwm. Eg your suggested diode TPD4E02B04-Q1 has only 3.6 working voltage and if Poc is 5V,9V or 12V it won work.

Do you see any draw-back if using the ESD diode and a series resistor like in the slvaf60a app note? (TPD1E01B04-Q1 )

Are you aware of any layout that follows slvaf60a app-note, or did TI do any test with slvaf60a set-up?

Best Regards,

d.

  • 0
    TI__Genius 9955 points

    Hello D,

    We typically recommend to place the ESD diode between the connector and the AC coupling capacitor as mentioned in the E2E linked by Kenneth. As mentioned, the ESD diode will need to have a standoff voltage higher than Vpoc. The solution pictured in the application note, in which the ESD diode is placed before the AC coupling capacitor can also be used but, is not our recommended solution. In this case, the TVS diode suggested would need to be placed as shown in Figure 2. Selecting an ESD diode with a higher standoff voltage will enable the recommendation to place the ESD diode between the connector and the AC coupling capacitor.

    Our devices have been tested to the ESD ratings in the datasheet based on internal ESD protection, without any external ESD diodes. 

    Please let me know if you have any additional questions on this topic.

    Best,

    Zoe

  • 0 in reply to Zoe Bison
    Genius 4440 points

    Hi Zoe,

    After looking to place the ESD diode between connector and AC cap, we need a low capacitance diode with high reverse stand-of voltage because of PoC is 12V.
    TI have eg. TPD1E01B04-Q1 but Vrwm is 3.6V max
    I then looked for ESD form another manufacturer and found some, can we have your comment and feedback if those diodes will work with FPDLink regarding the capacitance loading?
    Diodes DESD18VF1BLQ
    Littelfuse AQ3118
    Nexperia PESD18VF1BL-Q
    Onesemi SZESD7462
    Semtech RClamp1561PQ
    Best Regards,
    d.
  • +1 in reply to d_zero
    TI__Genius 14115 points

    Hi d,

    All of these ESD diodes meet the VRWM requirement and have low capacitance. You will need to select which one you wish to use.

    Best,

    Lucas