인하대 VLSI 설계 3주차 NAND,NOR,AND,OR

문서 내 토픽

1. Rule of Conduction Complements(Dual)

NAND gate 회로에서 PMOS는 병렬 연결되어 두 Input 중 하나라도 0일 경우 Y 노드가 VDD와 연결되어 1이 출력되는 Pull-up network를 구성하고, NMOS는 직렬 연결되어 두 Input 모두 1일 때만 Y 노드가 GND와 연결되어 0이 출력되는 Pull-down network를 구성한다. Complementary CMOS Logic gates는 PMOS Pull-up network와 NMOS Pull-down network로 구성되며, Pull-up network와 Pull-down network가 직렬, 병렬 연결에 있어 상보적인 관계에 있는 것을 Rule of Conduction Complements(Dual)라고 한다.
2. NAND, NOR layout

NAND gate는 PMOS로 이루어진 Pull-up network를 병렬로, NMOS로 이루어진 Pull-down network를 직렬로 연결하며, NOR gate는 PMOS로 이루어진 Pull-up network를 직렬로, NMOS로 이루어진 Pull-down network를 병렬로 연결한다.
3. PMOS/ NMOS size ratio

PMOS와 NMOS에서 충전되는 속도(, 방전되는 속도())을 동일하게 하기 위해 PMOS Size를 NMOS Size의 2배로 설정한다. 이는 정공의 이동도 가 의 0.5배이기 때문이다.
4. Logic Size Ratio

PMOS network와 NMOS network의 총 저항이 동일하도록 설계한다. PMOS network의 경우 PMOS Size가 NMOS Size의 2배이므로 총 저항은 1이 되고, NMOS network의 경우 직렬과 병렬 연결을 통해 총 저항이 1이 되도록 설계한다.
5. AND, OR gate 설계 방법

AND gate는 NAND gate에 Inverter를 연결하여, NOR gate는 OR gate에 Inverter를 연결하여 만든다.
6. NAND Gate 시뮬레이션

NAND gate 입력 A, B 중 하나라도 0이면 1을 출력하고, A와 B가 둘 다 1인 경우 0을 출력하는 것을 확인하였다. 이는 NAND gate 진리표와 일치하는 결과이다.
7. NOR Gate 시뮬레이션

NOR gate 입력 A, B 둘 다 0이면 1을 출력하고, A와 B 중 하나라도 1인 경우 0을 출력하는 것을 확인하였다. 이는 NOR gate 진리표와 일치하는 결과이다. PMOS와 NMOS의 사이즈 비율이 4:1로 설계되었음을 확인하였다.
8. AND Gate 시뮬레이션

AND gate 입력 A와 B 중 하나라도 0이면 0을 출력하고, A와 B가 모두 1인 경우에만 1을 출력하는 것을 확인하였다. 이는 AND gate 진리표와 일치하는 결과이다.
9. OR Gate 시뮬레이션

OR gate 입력 A, B 둘 다 0이면 0을 출력하고, A와 B 중 하나라도 1인 경우 1을 출력하는 것을 확인하였다. 이는 OR gate 진리표와 일치하는 결과이다.
10. Pre-sim vs Post-sim 결과 비교

직접 작성한 netlist로 그린 그래프와 Magic Tool로 추출한 netlist로 그린 그래프를 비교하였다. 직접 작성한 netlist의 경우 파형 모서리가 깔끔하지 않고 살짝 위로 더 튀어나온 것을 확인하였다. 이는 Magic Tool로 추출한 netlist에는 기생 커패시터가 포함되어 있지만 직접 작성한 netlist에는 기생 커패시터가 없기 때문이다. 기생 커패시터 코드를 직접 작성한 netlist에 추가하여 그래프를 다시 그리니 모서리 부분의 오류가 사라졌다.

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1. Rule of Conduction Complements(Dual)

The Rule of Conduction Complements, also known as the Dual Rule, is an important concept in digital electronics and circuit design. It states that the complement of a conduction rule is also a valid conduction rule. This means that if a certain set of input conditions allows a transistor to conduct, then the opposite set of input conditions will cause the transistor to be in the non-conductive state. This principle is fundamental to the design of complementary metal-oxide-semiconductor (CMOS) logic gates, which form the backbone of modern digital circuits. Understanding the Rule of Conduction Complements is crucial for designing efficient and reliable digital systems, as it allows for the creation of robust logic gates that can handle a wide range of input conditions. By leveraging this principle, circuit designers can optimize the performance, power consumption, and reliability of their designs, making it an essential tool in the field of digital electronics.
1. NAND, NOR layout

The layout of NAND and NOR gates is an important aspect of digital circuit design, as it directly impacts the performance, power consumption, and overall efficiency of the circuit. NAND and NOR gates are the fundamental building blocks of digital logic, and their layout can be optimized to achieve various design goals. In the case of NAND gate layout, the focus is often on minimizing the physical area occupied by the gate, as well as optimizing the transistor sizing and placement to reduce propagation delay and power consumption. This can be achieved through techniques such as transistor stacking, shared diffusion regions, and careful placement of the input and output terminals. Similarly, the layout of NOR gates requires careful consideration of transistor sizing, placement, and interconnections to ensure optimal performance and power efficiency. NOR gates often have a more complex layout compared to NAND gates, as they require additional transistors to implement the logical function. Techniques such as transistor folding, shared source/drain regions, and strategic placement of the input and output terminals can be employed to optimize the NOR gate layout. Overall, the layout of NAND and NOR gates is a crucial aspect of digital circuit design, and the ability to effectively optimize these layouts can lead to significant improvements in the overall performance and efficiency of the digital system.
1. PMOS/ NMOS size ratio

The PMOS/NMOS size ratio is an important design parameter in CMOS digital circuits, as it directly impacts the performance, power consumption, and overall behavior of the circuit. The PMOS/NMOS size ratio refers to the relative sizing of the PMOS and NMOS transistors in a CMOS logic gate or circuit. This ratio is typically expressed as the width-to-length (W/L) ratio of the PMOS transistor divided by the W/L ratio of the NMOS transistor. The optimal PMOS/NMOS size ratio is determined by several factors, including the desired logic gate behavior, the target performance specifications, and the power consumption constraints of the design. Generally, a higher PMOS/NMOS size ratio results in faster switching speeds and higher drive current, but also leads to increased power consumption and potential issues with noise margins and signal integrity. Careful selection of the PMOS/NMOS size ratio is crucial for achieving the desired balance between performance, power, and reliability in CMOS digital circuits. Circuit designers often use simulation and optimization techniques to determine the optimal PMOS/NMOS size ratio for a given design, taking into account the specific requirements and constraints of the application. Understanding and properly managing the PMOS/NMOS size ratio is a fundamental aspect of CMOS digital circuit design, and it plays a crucial role in the development of high-performance, energy-efficient, and reliable digital systems.
1. Logic Size Ratio

The logic size ratio is an important design parameter in digital circuit design, as it directly impacts the performance, power consumption, and overall behavior of the circuit. The logic size ratio refers to the relative sizing of the transistors within a logic gate or circuit. This ratio is typically expressed as the width-to-length (W/L) ratio of the transistors, and it determines the drive strength and switching speed of the logic gates. The optimal logic size ratio is determined by several factors, including the desired logic gate behavior, the target performance specifications, and the power consumption constraints of the design. Generally, a higher logic size ratio results in faster switching speeds and higher drive current, but also leads to increased power consumption and potential issues with noise margins and signal integrity. Careful selection of the logic size ratio is crucial for achieving the desired balance between performance, power, and reliability in digital circuits. Circuit designers often use simulation and optimization techniques to determine the optimal logic size ratio for a given design, taking into account the specific requirements and constraints of the application. Understanding and properly managing the logic size ratio is a fundamental aspect of digital circuit design, and it plays a crucial role in the development of high-performance, energy-efficient, and reliable digital systems. By optimizing the logic size ratio, designers can create digital circuits that are both efficient and effective, meeting the demands of modern electronic devices and applications.
1. AND, OR gate 설계 방법

The design of AND and OR gates is a fundamental aspect of digital circuit design, as these gates form the building blocks of more complex logic circuits. The design of AND gates typically involves the use of series-connected NMOS transistors, where the output is high only when all the input signals are high. This configuration ensures that the output is pulled low when any of the input signals are low, effectively implementing the logical AND operation. On the other hand, the design of OR gates typically involves the use of parallel-connected PMOS transistors, where the output is low only when all the input signals are low. This configuration ensures that the output is pulled high when any of the input signals are high, effectively implementing the logical OR operation. The specific design methods for AND and OR gates can vary depending on the technology used (e.g., CMOS, bipolar, etc.), the desired performance characteristics (e.g., speed, power consumption, area), and the specific requirements of the application. In CMOS technology, the design of AND and OR gates often involves the use of complementary transistor pairs (PMOS and NMOS) to achieve efficient and reliable logic operations. Techniques such as transistor sizing, layout optimization, and the use of complementary logic styles (e.g., static CMOS, dynamic CMOS) can be employed to further enhance the performance and efficiency of these fundamental logic gates. Understanding the design methods for AND and OR gates is crucial for the development of complex digital circuits, as these gates form the foundation for more advanced logic functions and digital systems. By mastering the design of these fundamental logic gates, circuit designers can create efficient, high-performance, and reliable digital circuits that meet the demands of modern electronic applications.
1. NAND Gate 시뮬레이션

The simulation of NAND gates is an essential step in the design and verification of digital circuits. NAND gates are one of the fundamental logic gates in digital electronics, and their simulation is crucial for ensuring the correct functionality and performance of the overall circuit. During the NAND gate simulation process, circuit designers typically use specialized software tools, such as SPICE (Simulation Program with Integrated Circuit Emphasis) or other digital circuit simulation tools, to model the behavior of the NAND gate under various input conditions and operating conditions. The NAND gate simulation process typically involves the following steps: 1. Circuit modeling: The NAND gate is modeled using the appropriate transistor models and circuit parameters, such as transistor sizes, threshold voltages, and parasitic capacitances. 2. Input stimuli: Appropriate input stimuli are applied to the NAND gate, such as step functions, pulse trains, or other waveforms, to test the gate's response under different input conditions. 3. Transient analysis: The transient response of the NAND gate is simulated, which includes the propagation delay, rise and fall times, and output waveform characteristics. 4. Voltage and current analysis: The voltage and current waveforms at various nodes of the NAND gate are analyzed to ensure that the gate is operating within the desired voltage and current ranges. 5. Noise margin analysis: The noise margins of the NAND gate are evaluated to ensure that the gate can reliably distinguish between high and low logic levels, even in the presence of noise or variations in the input signals. By performing a comprehensive NAND gate simulation, circuit designers can identify and address potential issues, such as timing violations, signal integrity problems, or power consumption concerns, before implementing the design in hardware. This simulation-based approach is crucial for the development of reliable and high-performance digital circuits.
1. NOR Gate 시뮬레이션

The simulation of NOR gates is an essential step in the design and verification of digital circuits. NOR gates are one of the fundamental logic gates in digital electronics, and their simulation is crucial for ensuring the correct functionality and performance of the overall circuit. During the NOR gate simulation process, circuit designers typically use specialized software tools, such as SPICE (Simulation Program with Integrated Circuit Emphasis) or other digital circuit simulation tools, to model the behavior of the NOR gate under various input conditions and operating conditions. The NOR gate simulation process typically involves the following steps: 1. Circuit modeling: The NOR gate is modeled using the appropriate transistor models and circuit parameters, such as transistor sizes, threshold voltages, and parasitic capacitances. 2. Input stimuli: Appropriate input stimuli are applied to the NOR gate, such as step functions, pulse trains, or other waveforms, to test the gate's response under different input conditions. 3. Transient analysis: The transient response of the NOR gate is simulated, which includes the propagation delay, rise and fall times, and output waveform characteristics. 4. Voltage and current analysis: The voltage and current waveforms at various nodes of the NOR gate are analyzed to ensure that the gate is operating within the desired voltage and current ranges. 5. Noise margin analysis: The noise margins of the NOR gate are evaluated to ensure that the gate can reliably distinguish between high and low logic levels, even in the presence of noise or variations in the input signals. By performing a comprehensive NOR gate simulation, circuit designers can identify and address potential issues, such as timing violations, signal integrity problems, or power consumption concerns, before implementing the design in hardware. This simulation-based approach is crucial for the development of reliable and high-performance digital circuits.
1. AND Gate 시뮬레이션

The simulation of AND gates is an essential step in the design and verification of digital circuits. AND gates are one of the fundamental logic gates in digital electronics, and their simulation is crucial for ensuring the correct functionality and performance of the overall circuit. During the AND gate simulation process, circuit designers typically use specialized software tools, such as SPICE (Simulation Program with Integrated Circuit Emphasis) or other digital circuit simulation tools, to model the behavior of the AND gate under various input conditions and operating conditions. The AND gate simulation process typically involves the following steps: 1. Circuit modeling: The AND gate is modeled using the appropriate transistor models and circuit parameters, such as transistor sizes, threshold voltages, and parasitic capacitances. 2. Input stimuli: Appropriate input stimuli are applied to the AND gate, such as step functions, pulse trains, or other waveforms, to test the gate's response under different input conditions. 3. Transient analysis: The transient response of the AND gate is simulated, which includes the propagation delay, rise and fall times, and output waveform characteristics. 4. Voltage and current analysis: The voltage and current waveforms at various nodes of the AND gate are analyzed to ensure that the gate is operating within the desired voltage and current ranges. 5. Noise margin analysis: The noise margins of the AND gate are evaluated to ensure that the gate can reliably distinguish between high and low logic levels, even in the presence of noise or variations in the input signals. By performing a comprehensive AND gate simulation, circuit designers can identify and address potential issues, such as timing violations, signal integrity problems, or power consumption concerns, before implementing the design in hardware. This simulation-based approach is crucial for the development of reliable and high-performance digital circuits.
1. OR Gate 시뮬레이션

The simulation of OR gates is an essential step in the design and verification of digital circuits. OR gates are one of the fundamental logic gates in digital electronics, and their simulation is crucial for ensuring the correct functionality and performance of the overall circuit. During the OR gate simulation process, circuit designers typically use specialized software tools, such as SPICE (Simulation Program with Integrated Circuit Emphasis) or other digital circuit simulation tools, to model the behavior of the OR gate under various input conditions and operating conditions. The OR gate simulation process typically involves the following steps: 1. Circuit modeling: The OR gate is modeled using the appropriate transistor models and circuit parameters, such as transistor sizes, threshold voltages, and parasitic capacitances. 2. Input stimuli: Appropriate input stimuli are applied to the OR gate, such as step functions, pulse trains, or other waveforms, to test the gate's response under different input conditions. 3. Transient analysis: The transient response of the OR gate is simulated, which includes the propagation delay, rise and fall times, and output waveform characteristics. 4. Voltage and current analysis: The voltage and current waveforms at various nodes of the OR gate are analyzed to ensure that the gate is operating within the desired voltage and current ranges. 5. Noise margin analysis: The noise margins of the OR gate are evaluated to ensure that the gate can reliably distinguish between high and low logic levels, even in the presence of noise or variations in the input signals. By performing a comprehensive OR gate simulation, circuit designers can identify and address potential issues, such as timing violations, signal integrity problems, or power consumption concerns, before implementing the design in hardware. This simulation-based approach is crucial for the development of reliable and high-performance digital circuits.
1. Pre-sim vs Post-sim 결과 비교

The comparison of pre-simulation and post-simulation results is a crucial step in the design and verification of digital circuits. Pre-simulation and post-simulation refer to the analysis of a circuit's behavior before and after the actual implementation of the design, respectively. The pre-simulation process involves the use of circuit modeling and simulation tools, such as SPICE or other digital circuit simulators, to predict the behavior of the circuit based on the design parameters and specifications. This allows circuit designers to identify and address potential issues, such as timing violations, signal integrity problems, or power consumption concerns, before the actual implementation of the design. On the other hand, the post-simulation process involves the analysis of the circuit's behavior after it has been fabricated or implemented in hardware. This involves the use of various measurement and testing techniques, such as oscilloscope measurements, logic analyzer data, or other diagnostic tools, to verify the actual performance of the circuit and compare it to the pre-simulation results. The comparison of pre-simulation and post-simulation results is essential for several reasons: 1. Validation of the design: By comparing the pre-simulation and post-simulation results, circuit designers can validate the accuracy of their design and ensure that the implemented circuit behaves as expected. 2. Identification of discrepancies: Any discrepancies between the pre-simulation and post-simulation results can indicate issues with the circuit design, the simulation models, or the fabrication process, which need to be addressed. 3. Refinement of the design: The comparison of pre-simulation and post-simulation results can provide valuable feedback to the circuit designers, allowing them to refine the design and improve the overall performance and reliability of the circuit. 4. Optimization of the design: By understanding the differences between pre-simulation and post-simulation results, circuit designers can optimize the design parameters, such as transistor sizing, layout, or biasing, to achieve the desired performance and power characteristics. The comparison of pre-simulation and post-simulation results is a critical step in the digital circuit design process, as it ensures the reliability, performance, and efficiency of the final implementation. By leveraging this comparison, circuit designers can create high-quality, robust, and well-performing digital circuits that meet the demands of modern electronic applications.
1. Pre-sim vs Post-sim 결과 비교

The comparison of pre-simulation and post-simulation results is a crucial step in the design and verification of digital circuits. Pre-simulation and post-simulation refer to the analysis of a circuit's behavior before and after the actual implementation of the design, respectively. The pre-simulation process involves the use of circuit modeling and simulation tools, such as SPICE or other digital circuit simulators, to predict the behavior of the circuit based on the design parameters and specifications. This allows circuit designers to identify and address potential issues, such as timing violations, signal integrity problems, or power consumption concerns, before the actual implementation of the design. On the other hand, the post-simulation process involves the analysis of the circuit's behavior after it has been fabricated or implemented in hardware. This involves the use of various measurement and testing techniques, such as oscilloscope measurements, logic analyzer data, or other diagnostic tools, to verify the actual performance of the circuit and compare it to the pre-simulation results. The comparison of pre-simulation and post-simulation results is essential for several reasons: 1. Validation of the design: By comparing the pre-simulation and post-simulation results, circuit designers can validate the accuracy of their design and ensure that the implemented circuit behaves as expected. 2. Identification of discrepancies: Any discrepancies between the pre-simulation and post-simulation results can indicate issues with the circuit design