It primarily focuses on timing, power and area optimization by applying different optimization techniques at each stage of the design. Clock Tree Synthesis (CTS) is an important step in physical design flow. CTS builds the clock tree by balancing the skew in the entire design for all the clocks present.
Why do we use a clock tree?
Clock Tree Synthesis is a process which makes sure that the clock gets distributed evenly to all sequential elements in a design. The goal of CTS is to minimize the skew and latency. … Less clock tree inverters and buffers should be used to meet the area and power constraints.
What is clock tree balancing?
CTS is the process of connecting the clocks to all clock pin of sequential circuits by using inverters/buffers in order to balance the skew and to minimize the insertion delay. All the clock pins are driven by a single clock source. Clock balancing is important for meeting all the design constraints.
What is CCD in VLSI?
A charge-coupled device (CCD) is an integrated circuit containing an array of linked, or coupled, capacitors. … CCD sensors are a major technology used in digital imaging. In a CCD image sensor, pixels are represented by p-doped metal–oxide–semiconductor (MOS) capacitors.
What is congestion in VLSI?
What is Congestion? If the number of routing tracks available for routing in one particular area is less than the required routing tracks then the area said to be congested. There will be a limit for number of nets that can be routed through particular area.
Why do we check setup before CTS?
Before CTS, clock is ideal that means exact skew is not there. All the clocks reaching the flops at the same time. So, we don’t have skew and transition numbers of the clock path, but this information is sufficient to perform setup analysis since setup violations depends on the data path delay.
What is clock tree design?
A clock tree is a clock distribution network within a system or hardware design. It includes the clocking circuitry and devices from clock source to destination. The complexity of the clock tree and the number of clocking components used. depends on the hardware design.
What are clock buffers used for?
Clock buffer is typically used to fan out clock signal and isolate the source from the loads.
What is concurrent clock and data optimization?
Clock concurrent optimization (CCOpt) is a revolutionary new approach to timing optimization: it merges physical optimization into clock tree synthesis and simultaneously optimizes clock delay and logic delay using a single unified cost metric.
What is difference between normal buffer and clock buffer?
Clock buffers have equal rise and fall time. … This prevents duty cycle of clock signal from changing when it passes through a chain of clock buffers. Normal buffers are designed with W/L ratio such that sum of rise time and fall time is minimum.
Why clock inverters are preferred over clock buffers?
1. Advantage of using an inverter based clock tree is that the high pulse width and the low pulse width would be symmetrical. For the clock signal, this is a critical requirement, especially for SoCs which have a high interaction between the positive and negative edge triggered flip-flops.
Which is better buffer or inverter?
In most of the library files, a buffer is the combination of two inverters so we can say that inverter will be having lesser delay than buffer with the same drive strength. Also inverters having more driving capacity than a buffer that’s why most of the libraries preferred inverter over buffer for CTS.