Cadence IC 模擬 PLL Loop Gain 問題

我系統是Ubuntu 10.04
Cadence IC: 615
MMSIM: 10.1
我用Cadence 的 pllLib 範例做 PLL Loop GAIn 模擬 (verilog-A)
DC Simulation 沒問題
跑AC Simulation 就停住了
請問有人遇到這種狀況嗎?
Log 內容:

Cadence (R) virtuoso (R) Spectre (R) Circuit Simulator
Version 10.1.0.204 32bit -- 14 Sep 2010
Copyright (C) 1989-2010 Cadence Design Systems, Inc. All rights reserved worldwide. Cadence, Virtuoso and Spectre are registered trademarks of Cadence Design Systems, Inc. All others are the property of their respective holders.
Protected by U.S. Patents:
5,610,847; 5,790,436; 5,812,431; 5,859,785; 5,949,992; 5,987,238;
6,088,523; 6,101,323; 6,151,698; 6,181,754; 6,260,176; 6,278,964;
6,349,272; 6,374,390; 6,493,849; 6,504,885; 6,618,837; 6,636,839;
6,778,025; 6,832,358; 6,851,097; 6,928,626; 7,024,652; 7,035,782;
7,085,700; 7,143,021; 7,493,240; 7,571,401.
Includes RSA BSAFE(R) Cryptographic or Security Protocol Software from RSA Security, Inc.
User: weis1982Host: ubuntuHostID: 7F0101PID: 8958
Memoryavailable: 92.2460 MBphysical: 3.1056 GB
cpu Type: Intel(R) Core(TM) i5 CPUM 450@ 2.40GHz
Processor PhysicalID CoreID Frequency

Simulating `input.scs' on ubuntu at 10:49:55 PM, Wed Oct 2, 2013 (process id: 8958).
Command line:
\
/home/weis1982/cadence/installs/mmsim10.1/tools.lnx86/spectre/bin/32bit/spectre\
input.scs +escchars +log ../psf/spectre.out +inter=mpsc\
+mpssession=spectre2_8627_3 -format sst2 -raw ../psf +lqtimeout\
900 -maxw 5 -maxn 5
spectre pid = 8958
Loading /home/weis1982/cadence/installs/mmsim10.1/tools.lnx86/cmi/lib/5.0/libinfineon_sh.so ...
Loading /home/weis1982/cadence/installs/mmsim10.1/tools.lnx86/cmi/lib/5.0/libphilips_sh.so ...
Loading /home/weis1982/cadence/installs/mmsim10.1/tools.lnx86/cmi/lib/5.0/libsparam_sh.so ...
Loading /home/weis1982/cadence/installs/mmsim10.1/tools.lnx86/cmi/lib/5.0/libstmodels_sh.so ...
Time for NDB Parsing: CPU = 860 ms, elapsed = 1.23636 s.
Time accumulated: CPU = 860 ms, elapsed = 1.23636 s.
Peak resident memory used = 29.1 Mbytes.

Time for Elaboration: CPU = 30 ms, elapsed = 95.7201 ms.
Time accumulated: CPU = 890 ms, elapsed = 1.33723 s.
Peak resident memory used = 36.9 Mbytes.

Time for EDB Visiting: CPU = 0 s, elapsed = 4.27914 ms.
Time accumulated: CPU = 890 ms, elapsed = 1.34593 s.
Peak resident memory used = 37.1 Mbytes.

Circuit inventory:
nodes 5
capacitor 1
resistor 1
sinusoidal_phase_detector 1
vco_tuning_curve 1
vsource 2

Time for parsing: CPU = 10 ms, elapsed = 17.9491 ms.
Time accumulated: CPU = 900 ms, elapsed = 1.36431 s.
Peak resident memory used = 37.7 Mbytes.
Entering remote command mode using MPSC service (spectre, ipi, v0.0, spectre2_8627_3, ).
******************
DC Analysis `dcOp'
******************
Important parameter values:
reltol = 1e-03
abstol(V) = 1 uV
abstol(I) = 1 pA
temp = 27 C
tnom = 27 C
tempeffects = all
gmin = 1 pS
Convergence achieved in 4 iterations.
Total time required for dc analysis `dcOp': CPU = 0 s, elapsed = 4.01592 ms.
Time accumulated: CPU = 900 ms, elapsed = 1.41371 s.
Peak resident memory used = 38.2 Mbytes.
dcOpInfo: writing operating point information to rawfile.
*******************************************
AC Analysis `ac': freq = (10 Hz -> 100 kHz)
*******************************************
Notice from spectre during AC analysis `ac'.
Operating points will not be recomputed: the circuit and conditions were not changed since previous analysis.

没看出啥问题啊！不是跑了吗?是不是没设step?