Power semiconductors

What maximum junction temperature (Tj max) is commonly specified for typical silicon power devices?

  1. AAbout 500 °C
  2. BAbout 50 °C
  3. CAbout 150 to 175 °C
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Answer: C. About 150 to 175 °C

Silicon power devices commonly have a maximum junction temperature of 150 °C or 175 °C. Above this, increased leakage, thermal runaway and shortened lifetime become likely. SiC as a material withstands higher temperatures, but the heat resistance of packages and bonding materials becomes the limit.

  • A. About 500 °C is far too high for silicon device ratings.
  • B. About 50 °C would be exceeded even in normal operation.
  • C. Correct. 150 to 175 °C is typical.
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More Power semiconductors questions

  1. When choosing power devices, why are devices with a voltage rating higher than the actual operating voltage used (derating)?
  2. When does the avalanche ruggedness of a power MOSFET become important?
  3. What is a typical failure seen in power cycling tests, which repeatedly heat and cool power modules?
  4. In packages for fast-switching power devices, what is the purpose of a dedicated source terminal for the gate-drive return (Kelvin source)?
  5. Which circuit uses a diode and capacitor to create a gate voltage above the supply to drive the upper (high-side) n-channel MOSFET of a half bridge?