en

IC Packagers: Five Steps to IC-Driven Package Design

They say Moore's law is slowing. It may be slowing but it is still running - it has not stopped! And, it has been running at full throttle for quite a few decades now.  The net result of this run? Well, you can't design ICs in isolation from the...(read more)



  • Allegro Package Designer

en

IC Packagers: The Different Types of Mirrors

I’m not talking about carnival funhouse mirrors, but rather the different options for mirroring symbols, vias, and bond fingers in your IC Package layout. The Allegro Package Designer Plus and SiP Layout tools have two distinct styles of m...(read more)



  • Allegro Package Designer

en

IC Packagers: Design Element Label Management

  A few weeks ago, we talked about template text labels for design-specific information. There, we were focused on labels that are specific to the design as a whole: revision information, dates, authors, etc. Today, we’re looking at a diff...(read more)



  • Allegro Package Designer
  • Allegro PCB Editor

en

IC Packagers: Identify Your Components

We’ve all seen bar codes and the more modern QR codes. They’re everywhere you go – items at the grocery store, advertisements and posters, even on websites. Did you know that, with the productivity toolbox in Allegro Package Designe...(read more)



  • Allegro Package Designer
  • Allegro PCB Editor

en

IC Packagers: A New Option in Bond Finger Solder Mask Openings

If you design wire bond packages, you’re familiar with the need for the bond fingers and rings on the package substrate layers to be exposed through the solder mask layer. If they aren’t, it becomes… rather difficult… to bon...(read more)



  • Allegro Package Designer

en

IC Packagers: Time-Saving Alternatives to Show Element

In the Allegro back-end layout products like Allegro Package Designer Plus, it would be reasonable to assume that the most often used command is none other than “show element” (shortcut key F4). This command, runnable at nearly any t...(read more)



  • Allegro Package Designer
  • Allegro PCB Editor

en

Extrowords #97: Generalissimo 68

Sample clues

18 across: Makoto Hagiwara and David Jung both claim to have invented it (7,6)

1 down: French impressionist who rejected that term (5)

3 down: Artificial surface used for playing hockey (9)

7 down: The sequel to Iliad (7)

12 down: Adipose tissue (4,3)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Extrowords #98: Generalissimo 69

Sample clues

6 across: Franchise revived by Frank Miller (6)

13 across: What Keanu Reeves and Zayed Khan have in common (5)

18 across: What Frank Sinatra and George Clooney have in common (6,6)

19 across: Dosa mix, for example (6)

2 down: Green, in a non-environmental way (7)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Extrowords #99: Generalissimo 70

Sample clues

5 down: Torso covering (6)

7 down: Government by rogues (12)

15 across: eBay speciality (7)

18 across: Demonic (8)

20 across: Common language (6,6)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Extrowords #100: Generalissimo 71

Sample clues

17 across: Beckham speciality (4,4)

4 down: Havana speciality (5)

19 across: Infamous 1988 commercial against Michael Dukakis (9,4)

11 down: Precisely (2,3,3)

13 down: City infamously ransacked by the Japanese in 1937 (7)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Extrowords #101: Generalissimo 72

Sample clues

11 across: Chandigarh’s is 0172 (3,4)

21 across: He’s a loser, baby (4)

1 down: Garment meant to shape the torso (6)

12 down: It’s slogan: “Life, Liberty and the Pursuit” (8)

18 down: Noise made by badminton players? (6)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Extrowords #102: Generalissimo 73

Sample clues

5 across: The US president’s bird (3,5,3)

11 down: Group once known as the Quarrymen (7)

10 across: Cavalry sword (5)

19 across: Masonic ritual (5,6)

1 down: Pioneer of Ostpolitik (6)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Extrowords #103: Generalissimo 74

Sample clues

14 across: FDR’s baby (3,4)

1 down: A glitch in the Matrix? (4,2)

4 down: Slanted character (6)

5 down: New Year’s venue in New York (5,6)

16 down: Atmosphere of melancholy (5)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Extrowords #104: Generalissimo 74

Sample clues

6 across: Alejandro González Iñárritu’s breakthrough film (6,6)

19 across: Soft leather shoe (8)

7 down: Randroids, for example (12)

12 down: First American World Chess Champion (7)

17 down: Circle of influence (5)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Extrowords #105: Generalissimo 75

Sample clues

5 across: Robbie Robertson song about Richard Manuel (6,5)

2 down: F5 on a keyboard (7)

10 across: Lionel Richie hit (5)

3 down: ALTAIR, for example (5)

16 down: The problem with Florida 2000 (5)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Extrowords #106: Generalissimo 76

Sample clues

9 across: Van Morrison classic from Moondance (7)

6 down: Order beginning with ‘A’ (12)

6 across: Fatal weakness (8,4)

19 across: Rolling Stones classic (12)

4 down: Massacre tool (8)

Extrowords © 2007 IndiaUncut.com. All rights reserved.
India Uncut * The IU Blog * Rave Out * Extrowords * Workoutable * Linkastic




en

Production files generation

I have a question regarding the production files of a PCB. I have added two cutouts on my PCB.
When I generate my drill file these do not appear, only the holes of the tracks and the insert components appear. What do I need to do to make cutouts appear in my drill file?




en

Multiple parts for single reference designator

Variants seem to be defined as present or not present.

Is there a variant that can assign different parts to the same reference designator? i.e.  R17 can be either 0 ohm 0805 jumper or 12k ohms 0805 resistor.

The simplest way I can think of is to use two parts with the same footprint and overlay them.

Is there a more functional way of doing this?  So that the variant would put the correct part in the BOM and the parts would of course have the same identical footprint.




en

Placement by Schematic Page Problem (Not Displaying All Page)

I am using PCB Editor v17.2-2016.

I tried to do placement by schematic page but not all pages are displayed.

Earlier, I successfully do the placement by schematic pages and it was showing all the pages. But then I decided to delete all placed components and to do placement again.

When I try to do placement by schematic page again, I noticed that only the pages that I have successfully do all the placement previously are missing.




en

Why a new Package update generate DRC error after waiving ?

I've redesigned a custom TO220FLAT Package

First I created a TO220shape.ssm  with PCB Editor. Then I created a surface mount T220build.pad in Padstack Editor using TO220shape.ssm. Then I created a TO220FLAT.psm in PCB Editor. I placed 3 Connect pins and 9 Mechanical pins for the TO220 TAB, using standard through-hole pads for better current handling.

Adding those Mechanical pins created many DRC errors caused by the proximity of those pads attached to the TO220shape.

Thru Pin to SMD Pin Spacing (-200.0 0.0) 5 MIL OVERLAP DEFAULT NET SPACING CONSTRAINTS Mechanical Pin "Pad50sq30d" Pin "T220build, 2"

I corrected the situation (so I though) by Waiving those DRC errors, thinking that they could not cause any problem and because that’s what I want, i.e.: 9 through-holes under the TO220 device. The idea being that when this device is mounted flat on the PCB it could carry lots of current via 9 pads that could make a good high current conductor to inner layers.

I then saved the Package and updated all related footprint schematic parts  in Capture. Created a new Netlist. Then I imported the new logic into PCB Editor to reflect that change. When the File > Import > Logic is finished I get no feedback error! (which, for me is a substantial achievement in itself)

Now, in the Design Window I see all those DRC errors popping up again, despite the fact that I waived those DRCs back in the Padstack edition. If I run a Design Rule Check (DRC) Report I will see all those DRC listed again. Now, I understand that I can go ahead and waive all those DRCs (100 in total) but I’m thinking there is got to be a better way of doing this.

Please, any advise is welcome. Thanks

 




en

Is it possible to find or create a Pspice model for the JT3028, LD7552 components?

I would like to add these components to the component bank in ORCAD simulation. Even an accessible or free course that explained how to create these components.




en

Custom pad shape and symbol, when placed on pcb pad locations move.

Hi everybody,

I've created a symbol with custom pad shapes. Everything looks correct in the symbol editor.

And the 3d view looks correct (upside down to show placement)

But when I try to place it on the pcb the 2 "T" shaped pads aren't in the correct location.

I have the pad shape centered on the pad...

with no offset on the padstack editor.

Does anybody know how to fix this?

Thank you!




en

Allegro design entry DHL, pin swaps , export without exporting constraints, back annotate.

Hi,

I have a new customer that uses Allegro Design entry HDL for the schematic and have a few questions.

1. How do you get pin/gate swaps into the symbols in the schematic ?

2. How do you transfer them to the pcb editor ?

3. How do you back annotate the swaps from the pcb editor to the schematic ?

4. How do you stop the export/Import physical from updating the constraints in the pcb file ? 




en

trace ends from round to square?

Is it possible to change trace ends from round to square? Allegro PCB Designer 17.2 (basic)

Thanks




en

Specman Makefile generator utility

I've heard lots of people asking for a way to generate Makefiles for Specman code, and it seems there are some who don't use "irun" which takes care of this automatically. So I wrote this little utility to build a basic Makefile based on the compiled and loaded e code.

It's really easy to use: at any time load the snmakedeps.e into Specman, and use "write makefile <name> [-ignore_test]".
This will dump a Makefile with a set of variables corresponding to the loaded packages, and targets to build any compiled modules.
Using -ignore_test will avoid having the test file in the Makefile, in case you switch tests often (who doesn't?).

It also writes a stub target so you can do "make stub_ncvlog" or "make stub vhdl" etc.

The targets are pretty basic, I thought it was more useful to #include this into the main Makefile and define your own more complex targets / dependencies as required.

The package uses the "reflection" facility of the e language, which is now documented since Specman 8.1, so you can extend this utility if you want (please share any enhancements you make).

 Enjoy! :-)

Steve.




en

IntelliGen Statistics Metrics Collection Utilility

As noted in white papers, posts on the Team Specman Blog, and the Specman documentation, IntelliGen is a totally new stimulus generator than the original "Pgen" and, as a result, there is some amount of effort needed to migrate an existing verification environment to fully leverage the power of IntelliGen.  One of the main steps in migrating code is running the linters on your code and adressing the issues highlighted. 

Included below is a simple utility you can include in your environment that allows you to collect some valuable statistics about your code base to allow you to better gauge the amount of work that might be required to migrate from Pgen to IntelliGen.  The ICFS statistics reported are of particular benefit as the utility not only identifies the approximate number of ICFSs in the environment, it also breaks the total number down according to generation contexts (structs/units and gen-on-the-fly statements) allowing you to better focus your migration efforts. 

IMPORTANT: Sometimes a given environment can trigger a large number of IntelliGen linting messages right off the bat.  Don't let this freak you out!  This does not mean that migration will be a long effort as quite often some slight changes to an environment remove a large number of identified issues.  I recently encountered a situation where a simple change to three locations in the environment, removed 500+ ICFSs!

The methods included in the utility can be used to report information on the following:
- Number of e modules
- Number of lines in the environment (including blanks and comments)
- Number and type of IntelliGen Guidelines linting messages
- Number of Inconsistently Connected Field Sets (ICFSs)
- Number of ICFS contexts and how many ICFSs per context
- Number of soft..select overlays found in the envioronment
- Number of Laces identified in the environment


To use the code below, simply load it before/after loading e-code and then
you can execute any of the following methods:

- sys.print_file_stats()             : prints # of lines and files
- sys.print_constraint_stats()   : prints # of constraints in the environment
- sys.print_guideline_stats()    : prints # of each type of linting message
- sys.print_icfs_stats()            : prints # of ICFSs, contexts and #ICFS/context
- sys.print_soft_select_stats() : prints # of soft select overlay issues
- sys.print_lace_stats()           : *Only works for SPMNv6.2s4 and later* prints # of laces identified in the environment

Each of the above calls to methods produces it's own log files (stored in the current working directory) containing relevant information for more detailed analysis.
- file_stats_log.elog : Output of "show modules" command
- constraint_log.elog : Output of the "show constraint" command
- guidelines_log.elog : Output of "gen lint -g" (with notification set to MAX_INT in order to get all warnings)
- icfs_log.elog       : Output of "gen lint -i" command
- soft_select_log.elog: Output of the "gen lint -s" command
- lace_log.elog       : Output of the "show lace" command


Happy generating!

Corey Goss




en

Sudoku solver using Incisive Enterprise Verifier (IEV) and Assertion-Driven Simulation (ADS)

Just in time for the holidays, inside the posted tar ball is some code to solve 9x9 Sudoku puzzles with the Assertion-Driven Simulation (ADS) capability of Incisive Enterprise Verifier (IEV). Enjoy! Joerg Mueller Solutions Engineer for Team Verify





en

Accurate delay measurement between two clocks

Hi,

I am currently struggling with measuring the delay between two clocks with a sufficient accuracy. The reference one is a fixed-phase clock, and the other one is a squared clock resulting of a circuit (kind of PLL) synthesis.
As I need to run a large amount of Monte-Carlo simulations in transient noise, I need to improve the simulation speed, while keeping a satisfactory delay measurement accuracy (<0.1ps), more specifically at 0V-crossings of the differential clocks. So I cannot simply set a max timestep <0.1ps as it would be far too long to simulate.
To sum up, I would need a very relaxed timestep on clock up and down levels, and a very short timestep only at rise/fall transitions.

For this purpose, I wrote a Verilog-A script
- using a timmer function to accurately emulate the reference clock 0V-crossing times (and get the related times with $abstime)
- using @(cross to get the 0V-crossing times of the synthesized clock: but this is not accurate enough (I see simulation noise around 3ps in Conservative). Indeed, the "cross" event occures at the simulation time following the effective 0V-crossing time; this could be sometimes >3ps, far not enough accurate for my purpose.
- I have tried to replace the cross with the "above" function, but it hasn't changed anything, whatever the time_tol value I put (<0.1ps for instance), the result is the same as with the "cross" function and the points are larger than >>0.1ps, weirdly.

So I have decided to give up Verilog-A to measure the delay between my two clocks.
I am currently trying to use the "delay" function of the Cadence Calculator as I guess it will "extrapolate" the time between two simulation points and therefore give a more accurate measurement of the 0V-crossing events, but when I try to compute the delay difference between the synthesized clock and the reference clock, it returns "0".

...

Could you please give me hints to dramatically improve my 0V-crossing time measurements while relaxing the simulation time?
- either by helping me in writing a more suitable Verilog-A script
- or by helping me in using the "delay" function of the calculator
- or maybe by providing me a "magic" Skill function?
Using AMS+Multithread simulator...

Thanks a lot in advance for your help and best regards.




en

ISF Function Extraction in Cadence Virtuoso

Hi all,

Is there any tutorial which explains the process of plotting the ISF function for a certain oscillator ?

Thank you.




en

Regarding Save/Restore Settings for Transient Simulation

Hello,

I am running a transient simulation on my circuit and usually my simulation time took me more than a day (The circuit is quite big). I am usually saving specific nodes to decrease the simulation time. My problem is, since it usually took me one day to finish I need to save my trans simulation just in case something bad happens. I am aware that the transient simulation have the options for save/restore. But, when I tried to use it I have some problem. Whenever I restore the save file, it starts where it ends before (expected function) but my data is incomplete. It doesn't save the previous data. Its kind of my data is incomplete. What I did is set the saveperiod and savefile. I hope someone can help me. Thank you!


Regards,

Kiel




en

Unable to Import .v files with `define using "Cadence Verilog In" tool

Hello,

I am trying to import multiple verilog modules defined in a single file with "`define" directive in the top using Verilog In. The code below is an example of what my file contains.

When I use the settings below to import the modules into a library, it imports it correctly but completely ignores all `define directive; hence when I simulate using any of the modules below the simulator errors out requesting these variables.

My question: Is there a way to make Verilog In consider `define directives in every module cell created? 

Code to be imported by Cadence Verilog In:

--------------------------------------------------------

`timescale 1ns/1ps
`define PROP_DELAY 1.1
`define INVALID_DELAY 1.3

`define PERIOD 1.1
`define WIDTH 1.6
`define SETUP_TIME 2.0
`define HOLD_TIME 0.5
`define RECOVERY_TIME 3.0
`define REMOVAL_TIME 0.5
`define WIDTH_THD 0.0

`celldefine
module MY_FF (QN, VDD, VSS, A, B, CK);


inout VDD, VSS;
output QN;
input A, B, CK;
reg NOTIFIER;
supply1 xSN,xRN;
buf IC (clk, CK);
and IA (n1, A, B);
udp_dff_PWR I0 (n0, n1, clk, xRN, xSN, VDD, VSS, NOTIFIER);
not I2 (QN, n0);

wire ENABLE_B ;
wire ENABLE_A ;
assign ENABLE_B = (B) ? 1'b1:1'b0;
assign ENABLE_A = (A) ? 1'b1:1'b0;

specify
$setuphold(posedge CK &&& (ENABLE_B == 1'b1), posedge A,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_B == 1'b1), negedge A, `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_A == 1'b1), posedge B, `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_A == 1'b1), negedge B, `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$width(posedge CK,1.0,0.0,NOTIFIER);
$width(negedge CK,1.0,0.0,NOTIFIER);
if (A==1'b0 && B==1'b0)
(posedge CK => (QN:1'bx)) = (1.0, 1.0);
if (A==1'b1 && B==1'b0)
(posedge CK => (QN:1'bx)) = (1.0, 1.0);
if (B==1'b1)
(posedge CK => (QN:1'bx)) = (1.0,1.0);

endspecify


endmodule // MY_FF
`endcelldefine

`timescale 1ns/1ps
`celldefine
module MY_FF2 (QN, VDD, VSS, A, B, CK);


inout VDD, VSS;
output QN;
input A, B, CK;
reg NOTIFIER;
supply1 xSN,xRN;
buf IC (clk, CK);
and IA (n1, A, B);
udp_dff_PWR I0 (n0, n1, clk, xRN, xSN, VDD, VSS, NOTIFIER);
not I2 (QN, n0);

wire ENABLE_B ;
wire ENABLE_A ;
assign ENABLE_B = (B) ? 1'b1:1'b0;
assign ENABLE_A = (A) ? 1'b1:1'b0;

specify
$setuphold(posedge CK &&& (ENABLE_B == 1'b1), posedge A,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_B == 1'b1), negedge A,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_A == 1'b1), posedge B,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_A == 1'b1), negedge B,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$width(posedge CK,1.0,0.0,NOTIFIER);
$width(negedge CK,1.0,0.0,NOTIFIER);
if (A==1'b0 && B==1'b0)
(posedge CK => (QN:1'bx)) = (1.0, 1.0);
if (A==1'b1 && B==1'b0)
(posedge CK => (QN:1'bx)) = (1.0, 1.0);
if (B==1'b1)
(posedge CK => (QN:1'bx)) = (1.0,1.0);

endspecify


endmodule // MY_FF2
`endcelldefine

--------------------------------------------------------

I am using the following Cadence versions:

MMSIM Version: 13.1.1.660.isr18

Virtuoso Version: IC6.1.8-64b.500.1

irun Version: 14.10-s039

Spectre Version: 18.1.0.421.isr9




en

Layout can't open with the following warning message in CIW

Hi,

I tried to open my layout by Library Manager, but the Virtuoso CIW window sometimes pops up the follow WARNING messages( as picture depicts). Thus, layout can't open.

Sometimes, I try to reconfigure ICADV12.3 by the iscape and restart my VM and then it incredibly works! But, often not!

So, If anyone knows what it is going on. Please let me know! Thanks!

Appreciated so much   




en

Wrong Constraint Values in Sequential Cell Characterization

Hi,

I am trying to characterize a D flip-flop for low voltage operation (0.6V) using Cadence Liberate (V16). This is a positive edge triggered D flip flop based on true-single-phase clocking scheme. After the characterization, the measurements reported for hold constraint arcs seem to deviate significantly from its (spectre) spice simulation.

The constraint and the power settings to the liberate are as follows : 

# -------------------------------------------- Timing Constraints --------------------------------------------------------------------------------
### Input waveform ###
set_var predriver_waveform 2;# 2=use pre-driver waveform
### Capacitance ###
set_var min_capacitance_for_outputs 1;# write min_capacitance attribute for output pins
### Timing ###
set_var force_condition 4
### Constraint ###
set_var constraint_info 2
#set_var constraint_search_time_abstol 1e-12 ;# 1ps resolution for bisection search
set_var nochange_mode 1 ;# enable nochange_* constraint characterization
### min_pulse_width ###
set_var conditional_mpw 0
set_var constraint_combinational 2


#---------------------------------------------- CCS Settings ----------------------------------------------------------------------------------------
set_var ccsn_include_passgate_attr 1
set_var ccsn_model_related_node_attr 1
set_var write_library_is_unbuffered 1

set_var ccsp_min_pts 15 ;# CCSP accuracy
set_var ccsp_rel_tol 0.01 ;# CCSP accuracy
set_var ccsp_table_reduction 0 ;# CCSP accuracy
set_var ccsp_tail_tol 0.02 ;# CCSP accuracy
set_var ccsp_related_pin_mode 2 ;# use 3 for multiple input switching scnarios and Voltus only libraries


#----------------------------------------------- Power ---------------------------------------------------------------------------------------------------
### Leakage ###
set_var max_leakage_vector [expr 2**10]
set_var leakage_float_internal_supply 0 ;# get worst case leakage for power switch cells when off
set_var reset_negative_leakage_power 1 ;# convert negative leakage current to 0

### Power ###
set_var voltage_map 1 ;# create pg_pin groups, related_power_pin / related_ground_pin
set_var pin_based_power 0 ;# 0=based on VDD only; 1=power based on VDD and VSS (default);
set_var power_combinational_include_output 0 ;# do not include output pins in when conditions for combinational cells

set_var force_default_group 1
set_default_group -criteria {power avg} ;# use average for default power group

#set_var power_subtract_leakage 4 ;# use 4 for cells with exhaustive leakage states.
set_var subtract_hidden_power 2 ;# 1=subtract hidden power for all cells
set_var subtract_hidden_power_use_default 3 ;# 3=subtract hidden power from matched when condition then default group
set_var power_multi_output_binning_mode 1 ;# binning for multi-output cell considered for both timing and power arcs
set_var power_minimize_switching 1
set_var max_hidden_vector [expr 2**10]
#--------------------------------------------------------------------------------------------------------------------------------------------------------------

I specifically used set_var constraint_combinational 2 in the settings, in case the Bisection pass/fail mode fails to capture the constraints. In my spice simulation, the hold_rise (D=1, CLK=R, Q=R) arc at-least requires ~250 ps for minimum CLK/D slew combination (for the  by default smallest capacitive load as per Liberate)  while Liberate reports only ~30 ps. The define_cell template to this flip flop is pretty generic, which does not have any user specified arcs. So which settings most likely affecting the constraint measurements in Liberate and how can I debug this issue ?

Thanks

Anuradha




en

Different Extracted Capacitance Values of the Same MOM Cap Structures Obtained from Quantus QRC Filed Solver

Hello,

 

I am using Virtuoso 6.1.7.

 

I am performing the parasitic extraction of a MOM cap array of 32 caps. I use Quantus QRC and I enable field solver. I select “QRCFS” for field solver type and “High” for field solver accuracy. The unit MOM cap is horizontally and vertically symmetric. The array looks like the sketch below and there are no other structures except the unit caps:

Rationally speaking, the capacitance values of the unit caps should be symmetric with respect to a vertical symmetry axis that is between cap16 and cap17 (shown with dashed red line). For example,

the capacitance of cap1 should be equal to the capacitance of cap32

the capacitance of cap2 should be equal to the capacitance of cap31

etc. as there are no other structures around the caps that might create some asymmetry.

Nevertheless, what I observe is the following after the parasitic extraction:

As it can be seen, the result is not symmetric contrary to what is expected. I should also add that I do not observe this when I perform parasitic extraction with no filed solver.

Why do I get this result? Is it an artifact resulting from the field solver tool (my conclusion was yes but still it must be verified)? If not, how can something like this happen?

 

Many thanks in advance.

 

Best regards,

Can




en

Delay Degradation vs Glitch Peak Criteria for Constraint Measurement in Cadence Liberate

Hi,

This question is related to the constraint measurement criteria used by the Liberate inside view. I am trying to characterize a specific D flip-flop for low voltage operation (0.6V) using Cadence Liberate (V16). 

When the "define_arcs" are not explicitly specified in the settings for the circuit (but the input/outputs are indeed correct in define_cell), the inside view seems to probe an internal node (i.e. master latch output)  for constraint measurements instead of the Q output of the flip flop. So to force the tool to probe Q output I added following coder in constraint arcs :

# constraint arcs from CK => D
define_arc
-type hold
-vector {RRx}
-related_pin CP
-pin D
-probe Q
DFFXXX

define_arc
-type hold
-vector {RFx}
-related_pin CP
-pin D
-probe Q
DFFXXX

define_arc
-type setup
-vector {RRx}
-related_pin CP
-pin D
-probe Q
DFFXXX

define_arc
-type setup
-vector {RFx}
-related_pin CP
-pin D
-probe Q
DFFXXX

with -probe Q liberate identifies Q as the output, but uses Glitch-Peak criteria instead of delay degradation method. So what could be the exact reason for this unintended behavior ? In my external (spectre) spice simulation, the Flip-Flop works well and it does not show any issues in the output delay degradation when the input sweeps.

Thanks

Anuradha




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Library Characterization Tidbits: Over the Clouds and Beyond with Arm-Based Graviton and Cadence Liberate Trio

Cadence Liberate Trio Characterization Suite, ARM-based Graviton Processors, and Amazon Web Services (AWS) Cloud have joined forces to cater to the High-Performance Computing, Machine Learning/Artificial Intelligence, and Big Data Analytics sectors. (read more)




en

Innovus Implementation System: What Is Stylus UI?

Hi Everyone,

Many of you would have heard about the Cadence Stylus Common UI and are wondering what it is and what the advantages might be to use it versus legacy UI.

The webinar answers the following questions:

  • Why did Cadence develop Stylus UI and what is Stylus Common UI?
  • How does someone invoke and use the Stylus Common UI?
  • What are some of the important and useful features of the Stylus Common UI?
  • What are the key ways in which the Stylus Common UI is different from the default UI?​

If you want to learn more about Stylus UI in the context of implementation, view the 45-minute recorded webinar on the Cadence support site.

Related Resource

Innovus Block Implementation with Stylus Common UI

 

Vinita Nelson




en

Genus Synthesis Solution – Introduction to Stylus Common UI

The Cadence® Genus  Synthesis Solution, Innovus  Implementation System, and Tempus  Timing Signoff Solution have a lot of shared functionality, but in the past, the separate legacy user interfaces (UIs) created a lot of differences.

A new common user interface that the Genus solution shares with the Innovus and Tempus solutions streamlines flow development and simplifies usability across the complete Cadence digital flow. The Stylus Common UI provides a next-generation synthesis-to-signoff flow with unified database access, MMMC timing configuration and reporting, and low-power design initialization.

This webinar answers the following questions:

  • What is the Stylus Common UI and why did Cadence develop it?
  • How does someone invoke and use the Stylus Common UI?
  • What are some of the important and useful features of the Stylus Common UI?
  • What are key ways the Stylus Common UI is different from the Legacy UI?

If you want to learn more about Stylus UI in the context of Genus Synthesis Solution, refer to 45-minute recorded webinar on https://support.cadence.com (Cadence login required).

Video Title: Webinar: Genus Synthesis Solution—Introduction to the Stylus Common UI (Video)

Direct Link: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O0V000009MoGIUA0&pageName=ArticleContent

Related Resources

If interested in the full course, including lab content, please contact your Cadence representative or email a request to training_enroll@cadence.com. You can also enroll in the course on http://learning.cadence.com.​

Enhance the Genus Synthesis experience with videos: Genus Synthesis Solution: Video Library

For any questions, general feedback, or future blog topic suggestions, please leave a comment. 




en

Exploring Genus-Joules Integration is just a click away!!

Joules RTL Power Solution provides a cockpit for RTL designers to explore and optimize the power efficiency of their designs. But this capability is now not just limited to RTL designers!! Yes, you as a synthesis designer too can use the power analysis capabilities of Joules from within Genus Synthesis Solution!!

But:

  • How to do it?
  • Is there any specific switch required?
  • What is the flow/script when Joules is used from within Genus?
  • Are all the Joules commands supported?

To answer to all these questions is just a click away in the form of video on “Genus-Joules Integration”; refer it on https://support.cadence.com (Cadence login required).

Video Title: Genus-Joules Integration (Video)

Direct Link: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O0V0000091CnXUAU&pageName=ArticleContent

 

Related Resources

Enhance the Genus Synthesis experience with videos: Genus Synthesis Solution: Video Library

Enhance the Joules experience with videos: Joules RTL Power Solution: Video Library

For any questions, general feedback, or future blog topic suggestions, please leave a comment. 




en

Automatically Reusing an SoC Testbench in AMS IP Verification

The complexity and size of mixed-signal designs in wireless, power management, automotive, and other fast growing applications requires continued advancements in a mixed-signal verification methodology. An SoC, in these fast growing applications, incorporates a large number of analog and mixed-signal (AMS) blocks/IPs, some acquired from IP providers, some designed, often concurrently. AMS IP must be verified independently, but this is not sufficient to ensure an SoC will function properly and all scenarios of interaction among many different AMS IP blocks at full chip / SoC level must be verified thoroughly. To reduce an overall verification cycle, AMS IP and SoC verification teams must work in parallel from early stages of the design. Easier said than done! We will outline a methodology than can help.

AMS designers verify their IP meets required specifications by running a testbench they develop for standalone / out of-context verification. Typically, an AMS IP as analog-centric, hierarchal design in schematic, composed of blocks represented by transistor, HDL and behavioral description verified in Virtuoso® Analog Design Environment (ADE) using Spectre AMS Designer simulation. An SoC verification team typically uses UVM SystemVerilog testbech at full chip level where the AMS IP is represented with a simple digital or real number model running Xcelium /DMS simulation from the command line.

Ideally, AMS designers should also verify AMS IP function properly in the context of full-chip integration, but reproducing an often complex UVM SystemVerilog testbench and bringing over top-level design description to an analog-centric environment is not a simple task.

Last year, Cadence partnered with Infineon on a project with a goal to automate the reuse of a top-level testbench in AMS verification. The automation enabled AMS verification engineers to automatically configure setup for verification runs by assembling all necessary options and files from the AMS IP Virtuoso GUI and digital SoC top-level command line configurations. The benefits of this method were:

  • AMS verification engineers did not need to re-create complex stimuli representing interaction of their IP at the top level
  • Top-level verification stays external to the AMS IP verification environment and continues to be managed by the SoC verification team, but can be reused by the AMS IP team without manual overhead
  • AMS IP is verified in-context and any inconsistencies are detected earlier in the verification process
  • Improved productivity and overall verification time

For more details, please see Infineon’s CDNLlive presentation.




en

Take Advantage of Advancements in Real Number Modeling and Simulation

Verification is the top challenge in mixed-signal design. Bringing analog and digital domains together into unified verification planning, simulating, and debugging is a challenging task for rapidly increasing size and complexity of mixed-signal designs. To more completely verify functionality and performance of a mixed-signal SoC and its AMS IP blocks used to build it, verification teams use simulations at transistor, analog behavioral and real-number model (RNM) and RTL levels, and combination of these.

In recent years, RNM and simulation is being adopted for functional verification by many, due to advantages it offers including simpler modeling requirements and much faster simulation speed (compared to a traditional analog behavioral models like Verilog-A or VHDL-AMS). Verilog-AMS with its wreal continue to be popular choice. Standardization of real number extensions in SystemVerilog (SV) made SV-RNM an even more attractive choice for MS SoC verification.

Verilog-AMS/wreal is scalar real type. SV-RNM offers a powerful ability to define complex data types, providing a user-defined structure (record) to describe the net value. In a typical design, most analog nodes can be modeled using a single value for passing a voltage (or current) from one module to another. The ability to pass multiple values over a net can be very powerful when, for example, the impedance load impact on an analog signal needs to be modeled. Here is an example of a user-defined net (UDN) structure that holds voltage, current, and resistance values:

When there are multiple drives on a single net, the simulator will need a resolution function to determine the final net value. When the net is just defined as a single real value, common resolution functions such as min, max, average, and sum are built into the simulator.  But definition of more complex structures for the net also requires the user to provide appropriate resolution functions for them. Here is an example of a net with three drivers modeled using the above defined structural elements (a voltage source with series resistance, a resistive load, and a current source):

To properly solve for the resulting output voltage, the resolution function for this net needs to perform Norton conversion of the elements, sum their currents and conductances, and then calculate the resolved output voltage as the sum of currents divided by sum of conductances.

With some basic understanding of circuit theory, engineers can use SV-RNM UDN capability to model electrical behavior of many different circuits. While it is primarily defined to describe source/load impedance interactions, its use can be extended to include systems including capacitors, switching circuits, RC interconnect, charge pumps, power regulators, and others. Although this approach extends the scope of functional verification, it is not a replacement for transistor-level simulation when accuracy, performance verification, or silicon correlation are required:  It simply provides an efficient solution for discretely modeling small analog networks (one to several nodes).  Mixed-signal simulation with an analog solver is still the best solution when large nonlinear networks must be evaluated.

Cadence provides a tutorial on EEnet usage as well as the package (EEnet.pkg) with UDN definitions and resolution functions and modeling examples. To learn more, please login to your Cadence account to access the tutorial.




en

Verifying Power Intent in Analog and Mixed-Signal Designs Using Formal Methods

Analog and Mixed-signal (AMS) designs are increasingly using active power management to minimize power consumption. Typical mixed-signal design uses several power domains and operate in a dozen or more power modes including multiple functional, standby and test modes. To save power, parts of design not active in a mode are shut down or may operate at reduced supply voltage when high performance is not required. These and other low power techniques are applied on both analog and digital parts of the design. Digital designers capture power intent in standard formats like Common Power Format (CPF), IEEE1801 (aka Unified Power Format or UPF) or Liberty and apply it top-down throughout design, verification and implementation flows. Analog parts are often designed bottom-up in schematic without upfront defined power intent. Verifying that low power intent is implemented correctly in mixed-signal design is very challenging. If not discovered early, errors like wrongly connected power nets, missing level shifters or isolations cells can cause costly rework or even silicon re-spin. 

Mixed-signal designers rely on simulation for functional verification. Although still necessary for electrical and performance verification, running simulation on so many power modes is not an effective verification method to discover low power errors. It would be nice to augment simulation with formal low power verification but a specification of power intent for analog/mixed-signal blocs is missing. So how do we obtain it? Can we “extract” it from already built analog circuit? Fortunately, yes we can, and we will describe an automated way to do so!

Virtuoso Power Manager is new tool released in the Virtuoso IC6.1.8 platform which is capable of managing power intent in an Analog/MS design which is captured in Virtuoso Schematic Editor. In setup phase, the user identifies power and ground nets and registers special devices like level shifters and isolation cells. The user has the option to import power intent into IEEE1801 format, applicable for top level or any of the blocks in design. Virtuoso Power Manager uses this information to traverse the schematic and extract complete power intent for the entire design. In the final stage, Virtuoso Power Manager exports the power intent in IEEE1801 format as an input to the formal verification tool (Cadence Conformal-LP) for static verification of power intent.

Cadence and Infineon have been collaborating on the requirements and validation of the Virtuoso Power Manager tool and Low Power verification solution on real designs. A summary of collaboration results were presented at the DVCon conference in Munich, in October of 2018.  Please look for the paper in the conference proceedings for more details. Alternately, can view our Cadence webinar on Verifying Low-Power Intent in Mixed-Signal Design Using Formal Method for more information.




en

Start Your Engines: AMSD Flex—Take your Pick!

Introduction to AMSD Flex mode and its benefits.(read more)



  • mixed signal design
  • AMS Designer
  • AMSD
  • AMSD Flex Mode
  • mixed-signal verification

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Start Your Engines: AMSD Flex – Your Instant Access to Latest Spectre Features!

This blog talks about how to enable the AMS Designer flex mode.(read more)



  • mixed signal design
  • AMS Designer
  • AMSD
  • AMSD Flex Mode
  • mixed-signal verification

en

Matlab cannot open Pspice, to prompt orCEFSimpleUI.exe that it has stopped working!

Cadence_SPB_17.4-2019 + Matlab R2019a

请参考本文档中的步骤进行操作

1,打开BJT_AMP.opj

2,设置Matlab路径

3,打开BJT_AMP_SLPS.slx

4,打开后,设置PSpiceBlock,出现或CEFSimpleUI.exe停止工作

5,添加模块

6,相同

7,打开pspsim.slx

8,相同

9,打开C: Cadence Cadence_SPB_17.4-2019 tools bin

orCEFSimpleUI.exe和orCEFSimple.exe

 

10,相同

我想问一下如何解决,非常感谢!




en

Virtuosity: Device Arrays in the Automated Device Placement and Routing Flow

Since the release of the Automated Device Placement and Routing solution last year, we have continued to improve and build upon it. In this blog, I’ll talk about the latest addition—the Auto Device Array form—how this is an integral piece of the new Automated Device Placement and Routing solution.(read more)




en

Virtuosity: Concurrently Editing a Hierarchical Cellview

This blog discusses key features of concurrently editing a hierarchical cellview.(read more)




en

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News18 Urdu: Latest News Mahendragarh

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