Semiconductor & Computer Engineering
From WikiChip
Difference between revisions of "cmos/static"
| Line 1: | Line 1: | ||
| − | '''Static [[CMOS]]''' is a [[logic gate|logic]] circuit design technique whereby the output is always strongly driven due to it always being connected to either [[VCC|V<sub>cc</sub>]] or [[GND]]. | + | '''Static [[CMOS]]''' is a [[logic gate|logic]] circuit design technique whereby the output is always strongly driven due to it always being connected to either [[VCC|V<sub>cc</sub>]] or [[GND]] (except when switching). This design is in contrast to [[Dynamic CMOS]] which relies on the temporary storage of signal using various load capacitances. |
== Overview == | == Overview == | ||
| Line 6: | Line 6: | ||
* pull-down network (PDN) - a set of [[NMOS]] transistors connected between GND and the output line | * pull-down network (PDN) - a set of [[NMOS]] transistors connected between GND and the output line | ||
| − | Components designed out pull-up and pull-down networks operate in a mutually exclusive way; in a steady state there is never a direct path between V<sub>cc</sub> and GND. Devices that are made up of PUN/PDN are always strongly driven and therefore | + | Components designed out pull-up and pull-down networks operate in a mutually exclusive way; in a steady state there is never a direct path between V<sub>cc</sub> and GND. Devices that are made up of PUN/PDN are always strongly driven and therefore offers strong immunity from noise. |
Revision as of 16:01, 13 March 2014
Static CMOS is a logic circuit design technique whereby the output is always strongly driven due to it always being connected to either Vcc or GND (except when switching). This design is in contrast to Dynamic CMOS which relies on the temporary storage of signal using various load capacitances.
Overview
A static CMOS circuit is composed of two networks:
- pull-up network (PUN) - a set of PMOS transistors connected between Vcc and the output line
- pull-down network (PDN) - a set of NMOS transistors connected between GND and the output line
Components designed out pull-up and pull-down networks operate in a mutually exclusive way; in a steady state there is never a direct path between Vcc and GND. Devices that are made up of PUN/PDN are always strongly driven and therefore offers strong immunity from noise.