Lecture 4_0916

26 temperature sensitivity increasing temperature

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Unformatted text preview: rts efforts to reduce subthreshold leakage using a negative gate voltage 4: Nonideal Transistor Theory CMOS CMOS VLSI Design 4th Ed. 26 Temperature Sensitivity Increasing temperature – Reduces mobility – Reduces Vt ION decreases with temperature IOFF increases with temperature 4: Nonideal Transistor Theory CMOS CMOS VLSI Design 4th Ed. 27 So What? So what if transistors are not ideal? – They still behave like switches. But these effects matter for… – Supply voltage choice – Logical effort – Quiescent power consumption – Pass transistors – Temperature of operation 4: Nonideal Transistor Theory CMOS CMOS VLSI Design 4th Ed. 28 Parameter Variation Transistors have uncertainty in parameters – Process: Leff, Vt, tox of nMOS and pMOS – Vary around typical (T) values Fast (F) – Leff: short – Vt: low – tox: thin Slow (S): opposite Not all parameters are independent for nMOS and pMOS 4: Nonideal Transistor Theory CMOS CMOS VLSI Design 4th Ed. 29 Environmental Variation VDD and T also vary in time and spa...
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