## What is NLDM and CCS?

VLSI characterization timing model. Keywords: CCS (Composite Current Source), NLDM (Non Linear Delay Model), SDM (Simplified Driver Model), STA (Static Timing Analysis)

**What is Ecsm library?**

The ECSM standard is the most complete open library format available and holistically models the effects of timing, noise, power, and variation. IP providers will benefit from greater simplicity and efficiency in the library creation process as well as a simplified distribution model.

**What is NLDM?**

The Non-linear Delay Model (NLDM) is the most common delay model for the characterization of standard cells. As we are going to deep sub-micron technology it requires more accurate timing models like CCS (composite current source)

### What does NLDM mean?

NLDM

Acronym | Definition |
---|---|

NLDM | Network Logical Data Manager |

NLDM | Non-Linear Delay Model |

**What is RC delay model?**

The RC delay model is a metric used in VLSI design to calculate the signal delay between the input voltage and output voltage of the input signal. The input signal is a step function. In this case the transistor can be considered as a switch in series with a resistor.

**What is linear delay model?**

Like most electrical systems, transistors can be modeled as a simple RC circuit where the width of the channel is modeled as a resistor while the space between the diffusion (i.e., source/drain) is modeled as a capacitor.

#### What is inverter delay?

The dynamic of performance of a logic-circuit family is characterized by the propagation delay of its basic. inverter. The inverter propagation delay (tP) is defined as the average of the low-to-high (tPLH) and the high-to- low (tPHL) propagation delays: 2.

**How is RC delay calculated?**

This transient response time T, is measured in terms of Ï„ = R x C, in seconds, where R is the value of the resistor in ohms and C is the value of the capacitor in Farads.

**What is RC in VLSI?**

## Does propagation delay depend on VDD?

The values of the equivalent resistances and even CL can depend on VDD thus the propagation delay is affected by power supply voltage (being smaller for higher VDD).

**What is the difference between NLDM and CCS driver?**

Other significant shortcoming of NLDM is in the receiver model. NLDM receiver model fails capture miller effect. This effects dominates delay calculation of STA for very small impedance nets. CCS driver model is characterized by capturing current waveform flowing into the load capacitor of the cell.

**Which two parameters are used to synthesize NLDM driver model?**

These two parameters – delay and transition times are used to synthesize NLDM driver model shown in the picture below: NLDM receiver model is simply a single capacitor for the entire transition with no sensitivity.

### What is the use of NLDM?

Most of the cell libraries used table models to specify the delay and timing checks for various timing arcs of the cell, the table model is referred to as an NLDM and are used for calculating the delay, output slew, or other timing checks.

**What is non-linear delay model (NLDM)?**

The Non-linear Delay Model (NLDM) is the most common delay model for the characterization of standard cells. As we are going to deep sub-micron technology it requires more accurate timing models like CCS (composite current source)