Sources of static power dissipation

• Static dissipation due to
• Subthreshold leakage through OFF transistors.
• Gate leakage through gate dielectric.
• Junction leakage from source/drain diffusions.
• Contention current in ratioed circuits.

2. Gate leakage:

• Gate leakage occurs when carriers tunnel through a thin gate dielectric, when a voltage is applied across the gate (e.g., when the gate is ON).
• Gate leakage is a strong function of the dielectric thickness.

3. Junction leakage:

• Junction leakage occurs when a source or drain diffusion region is at a different potential from the substrate.
• Leakage of reverse-biased diodes is usually negligible.

4. Contention current:

• Static CMOS circuits have no contention current. However, certain alternative circuits inherently draw current even while quiescent.