lets say, i am using a LTC4361 ic to protect an usb device from overvoltage and -current.

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Top Left is GND, below is VBUS, +5V is protected output. How would i deal with ESD protection for the 5V line? Using an USBLC6 would protect the following circuit from ESD, but would also just clamp the voltage down, if it is, for some reason, too high.

  • \$\begingroup\$ but would also just clamp the voltage down Which is also needed for ESD protection. The USBLC6 looks fine to me for ESD protection. If you want to protect the USB 5V against overvoltage damage then add a (poly) fuse in series with the 5 V at the connector so that the fuse blows when the USBLC6 clamps the voltage. An ESD will not be able to blow the fuse but that is to be expected. \$\endgroup\$ Mar 26 '19 at 15:14

The LTC4361 is a protective device. If it can hold up to 85V overvoltage in DC mode, it likely can hold a lot of 50-ns-long ESD events. Although the datasheet doesn't have explicit ESD data, the first page states: "No Input Capacitor or TVS Required for Most Applications". No "TVS", "Transient Voltage Suppressor". So your ESD concern is likely without much merit.

Also, the USBLC6 doesn't "just clamp" voltages above normal working level of USB, for normal voltages it clamps nothing, this is its function.

  • \$\begingroup\$ Maybe i worded my initial question poorly. The USBLC6 Datasheet claims a breakdown voltage of 6V between GND and VBUS. If there is a let's say 10V voltage difference between GND and VBUS, wouldn't the USBLC6 clamp it to 6V? And would the LTC4361 trigger from 50ns ESD events? \$\endgroup\$
    – lulle
    Mar 27 '19 at 18:53
  • \$\begingroup\$ @lulle, "clamping voltage" depends on internal impedance of voltage source. The USBLC6 starts conducting at 6V with 1 mA current, and if the source can supply 1A, then the clamping voltage goes to 12 V (and 17V at 5A). It is all in the datasheet. \$\endgroup\$ Mar 27 '19 at 19:03

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