MOSFET

In a MOSFET in saturation, what is the phenomenon in which raising the drain voltage shortens the effective channel length and slightly increases the drain current?

  1. ALatch-up
  2. BBody bias effect
  3. CChannel length modulation
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Answer: C. Channel length modulation

In saturation, a point where the channel disappears (the pinch-off point) forms at the drain end. Raising the drain voltage moves the pinch-off point toward the source, shortening the effective channel length and slightly increasing the drain current. This is channel length modulation, which determines the output resistance of an amplifier.

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