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[Solved] MTS temperature discrenpancy

Hi,

I am trying to use MTS just to compare two voltage values at two different temperatures (same models) in a single testbench.

Here I am simulating a bandgap core voltage vs. temp, so I set one cell to -40deg and the other to 125deg, but the values (especially at -40deg) looks wrong compared to the temperature DC sweep simulation (or even to the DC operating point at -40deg without MTS that matches the value from DC sweep).

In DC OP+MTS, I see a bandgap core voltage =1.216V for -40deg, whereas in the temperature DC sweep simulation I get 1.2257V.

What do I do wrong?

Thanks a lot in advance and best regards

Parents

threepwood06 over 5 years ago

Here is my output log:

Spectre (R) Circuit Simulator
Version 18.1.0.077 64bit -- 1 Aug 2018
Copyright (C) 1989-2018 Cadence Design Systems, Inc. All rights reserved worldwide. Cadence and Spectre are registered trademarks of Cadence Design Systems, Inc. All others are the property of their respective holders.

Includes RSA BSAFE(R) Cryptographic or Security Protocol Software from RSA Security, Inc.

User: ______ Host: _____ HostID: _____ PID: ___
Memory available: 6.9820 GB physical: 540.6396 GB
Linux : CentOS Linux release 7.7.1908 (Core)
CPU Type: Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz
Socket: Processors [Frequency] (Hyperthreaded Processor)
0: 0 [2600.0] ( 24 ), 2 [2889.5] ( 26 ), 4 [2145.7] ( 28 )
6 [2719.0] ( 30 ), 8 [2642.1] ( 32 ), 10 [2600.5] ( 34 )
12 [2599.8] ( 36 ), 14 [2774.7] ( 38 ), 16 [2600.0] ( 40 )
18 [2398.1] ( 42 ), 20 [2647.6] ( 44 ), 22 [2600.0] ( 46 )
1: 1 [2600.0] ( 25 ), 3 [2755.7] ( 27 ), 5 [2494.2] ( 29 )
7 [2947.4] ( 31 ), 9 [2646.5] ( 33 ), 11 [2682.4] ( 35 )
13 [2861.2] ( 37 ), 15 [2788.8] ( 39 ), 17 [2870.3] ( 41 )
19 [2792.5] ( 43 ), 21 [2884.4] ( 45 ), 23 [2825.7] ( 47 )

System load averages (1min, 5min, 15min) : 51.4 %, 55.9 %, 50.5 %
Hyperthreading is enabled

Simulating `input.scs' on jupiter at 3:42:52 PM, Tue Jun 16, 2020 (process id: 29503).
Current working directory: _________
Command line:
/tools/cadence/SPECTRE181/tools.lnx86/bin/spectre -64 input.scs \
+escchars +log ../psf/spectre.out -format psfxl -raw ../psf \
+mts +lqtimeout 0 +lqmmtoken -maxw 5 -maxn 5 +lorder MMSIM \
-ahdllibdir \
____________________
+logstatus

Loading /tools/cadence/_______________

______________

_________

__

Time for Elaboration: CPU = 40.939 ms, elapsed = 42.7141 ms.
Time accumulated: CPU = 1.50629 s, elapsed = 1.88181 s.
Peak resident memory used = 96.3 Mbytes.

Time for EDB Visiting: CPU = 1.23 ms, elapsed = 1.23096 ms.
Time accumulated: CPU = 1.50769 s, elapsed = 1.88322 s.
Peak resident memory used = 96.9 Mbytes.

Global user options:
ignorezerovar = yes
psfversion = 1.1.0
vabstol = 1e-06
iabstol = 1e-12
temp = 42.5
gmin = 1e-12
rforce = 1
maxnotes = 5
maxwarns = 5
digits = 5
cols = 80
pivrel = 0.001
sensfile = ../psf/sens.output
dochecklimit = yes
checklimitdest = both
save = allpub
reltol = 0.001
tnom = 27
scalem = 1
scale = 1

Scoped user options:
temp = 125 subckt=test_bgcore_core2
temp = -40 subckt=test_bgcore_core1

Circuit inventory:
nodes 8
bjt 18
capacitor 2
resistor 6
vcvs 2

Analysis and control statement inventory:
checklimit 1
dc 1
info 8

Output statements:
.probe 0
.measure 0
save 0

Notice from spectre.
17 warnings suppressed.

Time for parsing: CPU = 3.409 ms, elapsed = 22.6121 ms.
Time accumulated: CPU = 1.51125 s, elapsed = 1.90598 s.
Peak resident memory used = 98.2 Mbytes.

~~~~~~~~~~~~~~~~~~~~~~
Pre-Simulation Summary
~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~

******************
DC Analysis `dcOp'
******************

Opening the PSF file ../psf/dcOp.dc ...
Important parameter values:
reltol = 1e-03
abstol(V) = 1 uV
abstol(I) = 1 pA
temp = 42.5 C
tnom = 27 C
tempeffects = all
gmindc = 1 pS
Trying `homotopy = gmin'.

Notice from spectre during DC analysis `dcOp'.
Bad pivoting is found during DC analysis. Option dc_pivot_check=yes is recommended for possible improvement of convergence.

>>> What's this ?

Maximum value achieved for any signal of each quantity:
V: V(VBG_125) = 1.226 V
I: I(E5:p) = 245.8 uA
Convergence achieved in 426 iterations.
DC simulation time: CPU = 8.51 ms, elapsed = 9.13882 ms.
Total time required for dc analysis `dcOp': CPU = 8.561 ms, elapsed = 9.18508 ms.
Time accumulated: CPU = 1.52776 s, elapsed = 1.92337 s.
Peak resident memory used = 99.4 Mbytes.

dcOpInfo: writing operating point information to rawfile.

Opening the PSF file ../psf/dcOpInfo.info ...
modelParameter: writing model parameter values to rawfile.

Opening the PSF file ../psf/modelParameter.info ...
element: writing instance parameter values to rawfile.

Opening the PSF file ../psf/element.info ...
outputParameter: writing output parameter values to rawfile.

Opening the PSF file ../psf/outputParameter.info ...
designParamVals: writing netlist parameters to rawfile.

Opening the PSFASCII file ../psf/designParamVals.info ...
primitives: writing primitives to rawfile.

Opening the PSFASCII file ../psf/primitives.info.primitives ...
subckts: writing subcircuits to rawfile.

Opening the PSFASCII file ../psf/subckts.info.subckts ...
asserts: writing assert to rawfile.

Aggregate audit (3:42:54 PM, Tue Jun 16, 2020):
Time used: CPU = 1.66 s, elapsed = 2.21 s, util. = 74.8%.
Time spent in licensing: elapsed = 130 ms, percentage of total = 5.87%.
Peak memory used = 105 Mbytes.
Simulation started at: 3:42:52 PM, Tue Jun 16, 2020, ended at: 3:42:54 PM, Tue Jun 16, 2020, with elapsed time (wall clock): 2.21 s.
spectre completes with 0 errors, 5 warnings, and 2 notices.
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threepwood06 over 5 years ago

Here is my output log:

Spectre (R) Circuit Simulator
Version 18.1.0.077 64bit -- 1 Aug 2018
Copyright (C) 1989-2018 Cadence Design Systems, Inc. All rights reserved worldwide. Cadence and Spectre are registered trademarks of Cadence Design Systems, Inc. All others are the property of their respective holders.

Includes RSA BSAFE(R) Cryptographic or Security Protocol Software from RSA Security, Inc.

User: ______ Host: _____ HostID: _____ PID: ___
Memory available: 6.9820 GB physical: 540.6396 GB
Linux : CentOS Linux release 7.7.1908 (Core)
CPU Type: Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz
Socket: Processors [Frequency] (Hyperthreaded Processor)
0: 0 [2600.0] ( 24 ), 2 [2889.5] ( 26 ), 4 [2145.7] ( 28 )
6 [2719.0] ( 30 ), 8 [2642.1] ( 32 ), 10 [2600.5] ( 34 )
12 [2599.8] ( 36 ), 14 [2774.7] ( 38 ), 16 [2600.0] ( 40 )
18 [2398.1] ( 42 ), 20 [2647.6] ( 44 ), 22 [2600.0] ( 46 )
1: 1 [2600.0] ( 25 ), 3 [2755.7] ( 27 ), 5 [2494.2] ( 29 )
7 [2947.4] ( 31 ), 9 [2646.5] ( 33 ), 11 [2682.4] ( 35 )
13 [2861.2] ( 37 ), 15 [2788.8] ( 39 ), 17 [2870.3] ( 41 )
19 [2792.5] ( 43 ), 21 [2884.4] ( 45 ), 23 [2825.7] ( 47 )

System load averages (1min, 5min, 15min) : 51.4 %, 55.9 %, 50.5 %
Hyperthreading is enabled

Simulating `input.scs' on jupiter at 3:42:52 PM, Tue Jun 16, 2020 (process id: 29503).
Current working directory: _________
Command line:
/tools/cadence/SPECTRE181/tools.lnx86/bin/spectre -64 input.scs \
+escchars +log ../psf/spectre.out -format psfxl -raw ../psf \
+mts +lqtimeout 0 +lqmmtoken -maxw 5 -maxn 5 +lorder MMSIM \
-ahdllibdir \
____________________
+logstatus

Loading /tools/cadence/_______________

______________

_________

__

Time for Elaboration: CPU = 40.939 ms, elapsed = 42.7141 ms.
Time accumulated: CPU = 1.50629 s, elapsed = 1.88181 s.
Peak resident memory used = 96.3 Mbytes.

Time for EDB Visiting: CPU = 1.23 ms, elapsed = 1.23096 ms.
Time accumulated: CPU = 1.50769 s, elapsed = 1.88322 s.
Peak resident memory used = 96.9 Mbytes.

Global user options:
ignorezerovar = yes
psfversion = 1.1.0
vabstol = 1e-06
iabstol = 1e-12
temp = 42.5
gmin = 1e-12
rforce = 1
maxnotes = 5
maxwarns = 5
digits = 5
cols = 80
pivrel = 0.001
sensfile = ../psf/sens.output
dochecklimit = yes
checklimitdest = both
save = allpub
reltol = 0.001
tnom = 27
scalem = 1
scale = 1

Scoped user options:
temp = 125 subckt=test_bgcore_core2
temp = -40 subckt=test_bgcore_core1

Circuit inventory:
nodes 8
bjt 18
capacitor 2
resistor 6
vcvs 2

Analysis and control statement inventory:
checklimit 1
dc 1
info 8

Output statements:
.probe 0
.measure 0
save 0

Notice from spectre.
17 warnings suppressed.

Time for parsing: CPU = 3.409 ms, elapsed = 22.6121 ms.
Time accumulated: CPU = 1.51125 s, elapsed = 1.90598 s.
Peak resident memory used = 98.2 Mbytes.

~~~~~~~~~~~~~~~~~~~~~~
Pre-Simulation Summary
~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~

******************
DC Analysis `dcOp'
******************

Opening the PSF file ../psf/dcOp.dc ...
Important parameter values:
reltol = 1e-03
abstol(V) = 1 uV
abstol(I) = 1 pA
temp = 42.5 C
tnom = 27 C
tempeffects = all
gmindc = 1 pS
Trying `homotopy = gmin'.

Notice from spectre during DC analysis `dcOp'.
Bad pivoting is found during DC analysis. Option dc_pivot_check=yes is recommended for possible improvement of convergence.

>>> What's this ?

Maximum value achieved for any signal of each quantity:
V: V(VBG_125) = 1.226 V
I: I(E5:p) = 245.8 uA
Convergence achieved in 426 iterations.
DC simulation time: CPU = 8.51 ms, elapsed = 9.13882 ms.
Total time required for dc analysis `dcOp': CPU = 8.561 ms, elapsed = 9.18508 ms.
Time accumulated: CPU = 1.52776 s, elapsed = 1.92337 s.
Peak resident memory used = 99.4 Mbytes.

dcOpInfo: writing operating point information to rawfile.

Opening the PSF file ../psf/dcOpInfo.info ...
modelParameter: writing model parameter values to rawfile.

Opening the PSF file ../psf/modelParameter.info ...
element: writing instance parameter values to rawfile.

Opening the PSF file ../psf/element.info ...
outputParameter: writing output parameter values to rawfile.

Opening the PSF file ../psf/outputParameter.info ...
designParamVals: writing netlist parameters to rawfile.

Opening the PSFASCII file ../psf/designParamVals.info ...
primitives: writing primitives to rawfile.

Opening the PSFASCII file ../psf/primitives.info.primitives ...
subckts: writing subcircuits to rawfile.

Opening the PSFASCII file ../psf/subckts.info.subckts ...
asserts: writing assert to rawfile.

Aggregate audit (3:42:54 PM, Tue Jun 16, 2020):
Time used: CPU = 1.66 s, elapsed = 2.21 s, util. = 74.8%.
Time spent in licensing: elapsed = 130 ms, percentage of total = 5.87%.
Peak memory used = 105 Mbytes.
Simulation started at: 3:42:52 PM, Tue Jun 16, 2020, ended at: 3:42:54 PM, Tue Jun 16, 2020, with elapsed time (wall clock): 2.21 s.
spectre completes with 0 errors, 5 warnings, and 2 notices.
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