Tag: Vlsi

Why MIMCAP is needed? The geometry scaling has led to thinner interconnects and reduced metal width. Interconnect lengths were also increased along with switching at gigahertz speeds to meet complex design requirement. The device scaling has increased the density of integrated transistors on the semiconductor wafer. There may be large current spikes due to simultaneous… Continue reading Mim Cap In Vlsi

Variation Of Sources Causes of timing variations can include small variations in the way that features defined on a mask print on the surface of the chip because of the effect of surrounding features, variations in processes such as doping levels or etching that may remove more or less of a critical feature such as… Continue reading On Chip Variation Analysis

What is MMMC MMMC stands for: Multi-Mode Multi Corner  What’s a Mode A mode is defined by a set of clocks, supply voltages, timing constraints, and libraries. It can also have annotation data, such as SDF or parasitics files. Many chip have multiple modes such as functional modes, test mode, sleep mode, and etc. What’s… Continue reading Sta Multi Mode Multi Corner

Location coordinates are required to calculate path distance but are not required to calculate the path depth. Set the read_parasitics_load_locations variable to true, and then use the read_parasitics command  pt_shell> set_app_var read_parasitics_load_locations truept_shell> read_parasitics Enable POCV Analysis – To enable graph-based POCV analysis, set the timing_pocvm_enable_analysis variable to true  pt_shell> set_app_var timing_pocvm_enable_analysis true  Set Standard… Continue reading Synopsys Pocv Setup Commands

Report All Violations report_constraint –all_violators Report Number Of Violations The Number of Violations Report Path Timing Reports pt_shell> report_timing Report Clock Network report_clock_timing –type skew Report Bottleneck Analysis (Identify cells involved in multiple violations) report_bottleneck Specify Timing Assertions pt_shell> create_clock -name CLK -period 30 [get_port CLOCK]  pt_shell> set_clock_uncertainty 0.5 [all_clocks]  pt_shell> set_clock_latency -min 3.5 [get_clocks… Continue reading Synopsys Primetime Commands

Clock buffer have equal rise time and fall time, therefore pulse width violation is avoided. In clock buffers Beta ratio is adjusted such that rise & fall time are matched. This may increase size of clock buffer compared to normal buffer. Normal buffers may not have equal rise and fall time. Clock buffers are usually… Continue reading Difference Between Clock Buffer And Normal Buffer

Latch Based Clocking • Every cycle is broken by two latches   – That means that each signal must go through two latches   – So if you set clocks up correctly, hold time should not be bad      • Problem is each latch has a different clock, so skew can causehold time issues• But in this system there… Continue reading Latch Based Designs

Leakage Power Power Consumption consists of Dynamic Power and static Leakage Power. In this blog, we will talk mainly about static Leakage power dissipation. Leakage Power depends upon… Gate length Oxide thickness Threshold voltage etc. Leakage Power can be divided in two parts… Leakage Power in stand by mode Leakage Power in active mode Static… Continue reading Leakage Power

Clock gating occurrences are any signals on the clock path that block (gate) the clock from propagating.• The enable path of the clock gate must arrive enough time before the clock itself to ensure glitch-free functionality (and similarly hold after the edge). source Similar Snippets Clock Gating Check – vlsi Clock Tree Structure Types –… Continue reading Clock Gating Check

Clock Tree Structure Requirements Minimum Insertion Delay: A clock tree with minimum insertion delay will reduce clock tree power dissipation due to few clock tree buffers, uses less routing resources. Minimum skew: Minimum skew helps with hold timing closure. However, a tight skew requirement will lead to increase in clock insertion delay, which in turn… Continue reading Clock Tree Structure Types