What is complementary pass transistor logic?

Some authors use the term “complementary pass transistor logic” to indicate a style of implementing logic gates that uses transmission gates composed of both NMOS and PMOS pass transistors. Every CPL gate has two output wires, both the positive signal and the complementary signal, eliminating the need for inverters.

How do you implement pass transistor logic?

Pass Transistor Logic : The Pass transistor logic is required to reduce the transistors for implementing logic by using the primary inputs to drive gate terminals, source and drain terminals. In complementary CMOS logic primary inputs are allowed to drive only gate terminals.

What is NMOS pass transistor?

The nMOS pass-transistor logic uses only an nMOS transistor as the pass element as shown in Fig. 2(a). This gate passes logic ‘0’ efficiently but not logic ‘1’, and the gate delay is dependent on the input signal. The nMOS pass-transistor implemen- tation of the 4-to-1 multiplexer is shown in Fig.

What is pass transistor and transmission gate?

Pass-transistor logic (PTL), also known as transmission-gate logic, is based on the use of MOSFETs as switches rather than as inverters. The result is (in some cases) conceptual simplification, but the CMOS inverter’s strict logic-high/logic-low output characteristic is lost.

Which CMOS gate is faster?

NOR gates
100°C. fast as a conventional CMOS n-input gate. Somewhat surpris- ingly, multi-input symmetric NOR gates are faster than CMOS inverters (for fan-outs 2 3). This is a result of the parallel-PMOS topology, which allows each input terminal to control a smaller PMOS and a larger NMOS.

How does a CMOS inverter work?

CMOS Inverter The NMOS transistor has input from Vss (ground) and the PMOS transistor has input from Vdd. The terminal Y is output. When a high voltage (~ Vdd) is given at input terminal (A) of the inverter, the PMOS becomes an open circuit, and NMOS switched OFF so the output will be pulled down to Vss.

What is the difference between a pass transistor logic and transmission gate?

Transmission-Gate | Pass-Transistor-Logic i.e. NMOS devices passes a strong ‘0’ but a weak ‘1’ while PMOS transistors pass a strong ‘1’ but a weak ‘0’. The transmission gate combines the best of the two devices by placing an NMOS transistor in parallel with a PMOS transistor as shown in Figure below.

Why do we need both PMOS and NMOS transistors to implement a pass gate?

CMOS Transmission Gate Two MOS transistors are connected back-to-back in parallel with an inverter used between the gate of the NMOS and PMOS to provide the two complementary control voltages. When the input control signal, VC is LOW, both the NMOS and PMOS transistors are cut-off and the switch is open.

Why does NMOS pass strong zero?

Applying VDD at drain of nmos gives max voltage of VDD-Vth at the source side when gate voltage is VDD (Equation for nmos to turn ON: Vgs>Vds-Vth) while applying 0 at drain side of nmos gives 0 at the source side when gate voltage is VDD.

What is PMOS transistor?

A p-channel metal-oxide semiconductor (pMOS) transistor is one in which p-type dopants are used in the gate region (the “channel”). A negative voltage on the gate turns the device on.

Which gate is fastest?

Which gate is faster? Explanation: NOR gate is faster. NAND is more complex than NOR and thus NOR is faster and efficient.

How CMOS gates are very much power efficient?

CMOS logic dissipates less power than NMOS logic circuits because CMOS dissipates power only when switching (“dynamic power”). Static CMOS gates are very power efficient because they dissipate nearly zero power when idle.

How is complementary pass transistor logic used in solid state circuits?

Complementary Pass-transistor Logic (CPL)   “A 3.8 ns CMOS 16 x 16b Multiplier Using Complementary Pass -Transistor Logic” by K. Yano etc., IEEE J. of Solid-state Circuits, Vol 15, No 2, April 1990. •  Logic network employs input signals at both gate and drain terminals. •  Inputs and Outputs are always complementary.

Who is the author of pass transistor logic?

Lecture 11 Pass Transistor Logic Peter Cheung Department of Electrical & Electronic Engineering Imperial College London URL: www.ee.ic.ac.uk/pcheung/ E-mail: [email protected] Reading :“Top-Down Pass-Transistor Logic Design”, K. Yano etc., IEEE J. of Solid-State Circuits, Vol 31, No. 6, June 1996. Lecture 11 – 2 Recent development in PTL

What does 0 mean in pass transistor logic?

0 When B is “1”, top device turns on and copies the input A to output F. When B is low, bottom device turns on and passes a “0”. The presence of the switch driven by B is essential to ensure that the gate is static – a low-impedance path must exist to supply rails. Adv.: Fewer devices to implement some functions.

How are inputs and outputs of a logic network complementary?

•Logic network employs input signals at both gate and drain terminals. •Inputs and Outputs are always complementary. •Outputs from network provide strong ‘0’s but weak ‘1’s. Inverters and PMOS pull-ups provide amplificat ion and buffering as necessary. Lecture 11 – 4 Complementary Pass-transistor Logic (CPL)