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In digital electronics, a NAND gate (NOT-AND) is a logic gate which produces an output which is false only if all its inputs are true; thus its output is complement to that of an AND gate. A LOW (0) output results only if all the inputs to the gate are HIGH (1); if any input is LOW (0), a HIGH (1) output results.
A CMOS transistor NAND element. V dd denotes positive voltage.. In CMOS logic, if both of the A and B inputs are high, then both the NMOS transistors (bottom half of the diagram) will conduct, neither of the PMOS transistors (top half) will conduct, and a conductive path will be established between the output and Vss (ground), bringing the output low.
Propagation delay is the time taken for a two-input NAND gate to produce a result after a change of state at its inputs. Toggle speed represents the fastest speed at which a J-K flip flop could operate. Power per gate is for an individual 2-input NAND gate; usually there would be more than one gate per IC package. Values are very typical and ...
dual 4-input NAND gate Schmitt trigger 14 SN74LS18: 74x19 6 hex inverter gate Schmitt trigger 14 SN74LS19: 74x20 2 dual 4-input NAND gate 14 SN74LS20: 74x21 2 dual 4-input AND gate 14 SN74LS21: 74x22 2 dual 4-input NAND gate open-collector 14 SN74LS22: 74x23 2 dual 4-input NOR gate with strobe, one gate expandable with 74x60 16 SN7423: 74x24 4
Line reception: When running a data line that may have picked up noise into a logic gate it is necessary to ensure that a logic output level is only changed as the data changed and not as a result of spurious noise that may have been picked up. Using a Schmitt trigger broadly enables the peak to peak noise to reach the level of the hysteresis ...
The difference is that NAND logical gates are used in the gated D latch, while SR NAND latches are used in the positive-edge-triggered D flip-flop. The role of these latches is to "lock" the active output producing low voltage (a logical zero); thus the positive-edge-triggered D flip-flop can also be thought of as a gated D latch with latched ...
The output will be high (true) only when all gates are in the high-impedance state, and will be low (false) otherwise, like Boolean AND. When treated as active-low logic, this behaves like Boolean OR, since the output is low (true) when any input is low. See Transistor–transistor logic § Open collector wired logic.
As an example, consider the static logic implementation of a CMOS NAND gate: This circuit implements the logic function = ¯ If A and B are both high, the output will be pulled low. If either A or B are low, the output will be pulled high. At all times, the output is pulled either low or high.