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XNOR gates are represented in most TTL and CMOS IC families. The standard 4000 series CMOS IC is the 4077, and the TTL IC is the 74266 (although an open-collector implementation). Both include four independent, two-input, XNOR gates. The (now obsolete) 74S135 implemented four two-input XOR/XNOR gates or two three-input XNOR gates.
An XNOR gate is made by considering the disjunctive normal form + ¯ ¯, noting from de Morgan's law that a NAND gate is an inverted-input OR gate. This construction entails a propagation delay three times that of a single NAND gate and uses five gates.
quad 2-input NAND gate Schmitt trigger 14 SN74LS132: 74x133 1 single 13-input NAND gate 16 SN74ALS133: 74x134 1 single 12-input NAND gate three-state: 16 SN74S134: 74x135 4 quad XOR/XNOR gate, two inputs to select logic type 16 SN74S135: 74x136 4 quad 2-input XOR gate: open-collector 14 SN74LS136: 74x137 1
The 3-input Fredkin gate is functionally complete reversible gate by itself – a sole sufficient operator. There are many other three-input universal logic gates, such as the Toffoli gate. In quantum computing, the Hadamard gate and the T gate are universal, albeit with a slightly more restrictive definition than that of functional completeness.
An entire processor can be created using NOR gates alone. The original Apollo Guidance Computer used 4,100 integrated circuits (IC), each one containing only two 3-input NOR gates. [3] As NAND gates are also functionally complete, if no specific NOR gates are available, one can be made from NAND gates using NAND logic. [2]
This explains why "EQ" is often called "XNOR" in the combinational logic of circuit engineers, since it is the negation of the XOR operation; "NXOR" is a less commonly used alternative. [1] Another rationalization of the admittedly circuitous name "XNOR" is that one begins with the "both false" operator NOR and then adds the eXception "or both ...
Logic gates can be made from quantum mechanical effects, see quantum logic gate. Photonic logic gates use nonlinear optical effects. In principle any method that leads to a gate that is functionally complete (for example, either a NOR or a NAND gate) can be used to make any kind of digital logic circuit. Note that the use of 3-state logic for ...
The following is a list of CMOS 4000-series digital logic integrated circuits.In 1968, the original 4000-series was introduced by RCA.Although more recent parts are considerably faster, the 4000 devices operate over a wide power supply range (3V to 18V recommended range for "B" series) and are well suited to unregulated battery powered applications and interfacing with sensitive analogue ...