Nabcons Interview Questions and Answers

ICG stands for Inter-Chip Global. It is a network that connects multiple chips in a system.

• ICG is used to transfer data between different chips in a system

• It helps in reducing the number of wires required for communication between chips

• ICG can be used in various design aspects such as clock distribution, power management, and data transfer

• Example: In a multi-chip system, ICG can be used to transfer clock signals from one chip to another

Fixing setup and hold time violations simultaneously requires adjusting clock timing and/or data path delays.

• Identify the critical path causing the violations

• Adjust the clock timing to meet setup and hold requirements

• Adjust the data path delays to meet setup and hold requirements

• Use tools like static timing analysis and delay calculation to determine necessary adjustments

• Iteratively adjust timing and delays until violations are resolved

Antenna rules are guidelines to prevent signal interference in integrated circuits. Antenna violations can be fixed by various techniques.

• Antenna rules are design guidelines to prevent the formation of unintentional antennas in integrated circuits.

• These rules aim to minimize the risk of signal interference and ensure reliable circuit operation.

• Antenna violations occur when certain design features or structures unintentionally act as antennas, causing signal integrity issues.

• T...read more

A multiplexer can be used to design an AND gate by selecting the inputs and using the output as the AND gate output.

• Select two inputs of the multiplexer and connect them to the AND gate inputs.

• Connect the output of the multiplexer to the output of the AND gate.

• Set the select input of the multiplexer to 1 to enable the AND gate functionality.

• The truth table of the AND gate can be obtained from the truth table of the multiplexer.

• The logic equation of the AND gate can be derived...read more

MSCTS can help in achieving better clock distribution and reducing skew at SOC level CTS.

• MSCTS (Multi-Source Clock Tree Synthesis) can optimize the clock tree for better skew and jitter performance.

• It can also help in reducing power consumption by optimizing the clock network.

• MSCTS can handle multiple clock sources and ensure proper synchronization.

• It can also help in meeting timing constraints and reducing clock tree complexity.

• For example, in a complex SOC design with multi...read more

CMOS implementation of logic gates involves using complementary pairs of MOSFETs to create digital circuits.

• CMOS logic gates use both NMOS and PMOS transistors to achieve low power consumption and high noise immunity.

• The output of a CMOS gate is either connected to VDD or GND through a complementary pair of transistors.

• CMOS gates can be cascaded to create more complex digital circuits, such as adders and multipliers.

• Examples of CMOS logic gates include NAND, NOR, XOR, and inv...read more

Scan chain reorder is a technique used in DFT to optimize the order of scan chains for better test coverage.

• Scan chain reorder is used to optimize the order of scan chains in a design to improve test coverage.

• It involves rearranging the scan chains to minimize test application time and maximize fault coverage.

• Linux commands can be used for various DFT tasks such as file manipulation, script execution, and log analysis.

• DFT concepts include scan insertion, ATPG, fault simulatio...read more

Functional coverage is a metric used to measure how much of the design functionality has been exercised by the verification environment.

• Functional coverage is used to ensure that all the features of the design have been tested.

• It is a measure of how much of the design functionality has been exercised by the verification environment.

• Functional coverage is typically defined in terms of coverage points, which are specific aspects of the design that need to be tested.

• Coverage poi...read more