Sigrity SPEED2000 Power Ground Noise Simulation模式如何进行信号时域仿真操作指导(一)-单个信号
Power Ground Noise Simulation模式除了可以对电源进行时域仿真外，同样支持对信号进行时域仿真，以下图为例进行说明
2D视图
3D view
本例中观测信号D2从发送端U17到接收端U9的时域电压波形
具体操作如下
- 以下步骤参考Sigrity SPEED2000 Power Ground Noise Simulation模式如何进行电源阻抗仿真分析操作指导(一)-无电容
- 点击Add Excitation，添加激励，本例中是定义发送和接收端的模型参数
- 跳转到component Manager界面，选择drv1，将这个模型的node分别连接到layout node上的VCC,D2,GND
- 选中drv1，点击edit，定义drv1的spice语句如下
Gpmos Pvdd Out VCR PWL(1) 1000 1001 0 56 1.1109 237 1.2696 375 1.4283 705 1.46004 1021 1.49178 1805 1.49495 2021 1.49971 6021 IC=0
Gnmos Nvss Out VCR PWL(1) 1000 1001 0 6021 0.00476 2021 0.00793 1805 0.03967 1021 0.07141 705 0.23012 375 0.38882 237 1.49971 56 IC=0
Vvcr 1000 1001 sinesquar(0 1.5 0p 300p 300p 600p 2n )
rvcr 1000 1001 1
Rlarge 1001 Out 1000000
- 然后点击ok
- 同样地，将Rpd1，将它的ckt node1和2连接到layout node的D2和GND
- 选中Rpd1，点击edit，定义Rpd1参数如下
Rterm 1 2 70
终端电阻为70ohm
- 然后点击ok
- 同样地操作，将VCC连接到layout上，参数为
Vcc 1 0 1.5
定义为1.5v，理想直流电源
- 点击Specify Sim Time & Options，设置仿真时长为5ns，点击ok
- 点击Specify Observation (voltage)，定义发送和接收端的电压观测点
- 点击Auto mesh，error check waring，save，自动网格，错误检查和保存
- 点击start simulation，开始仿真
- 仿真结束后结果如下图
Drv1是发送端的时域电压曲线
Rpds1是接收端的时域电压曲线
- 由于阻抗线是74.52ohm，端接的70ohm的电阻，接收端波形较好
Along with accuracy and efficiency, SPEED2000 provides an analysis flow that is particularly
valuable for design simulations that benefit from direct time domain observation. SPEED2000
can read databases from popular package and board design tools.
Chip data can also be incorporated into the same file for co-simulation. This provides an
environment for accessing the impact of noise propagation throughout the entire structure.
Circuits in the combined design are linked with SPICE circuit files.
Simulation parameters and excitation are added by the user; however, the user does not need
to create special purpose models. SPEED2000 directly provides voltage and current
waveforms.
SPEED2000 is particularly effective to be used for, but it is not limited to, the following
applications:
■ Computation of power and ground noise.
■ Determination of decoupling capacitor placement, including the number, values, and
locations of decoupling capacitors
■ Determination of frequency-dependent port parameters of packages, such as port input
impedances, S parameters, and transfer functions between different ports
■ Evaluation and design of power and ground distribution systems, including power and
ground plane arrangement, and power and ground via / pin assignment
■ Evaluation of electromagnetic coupling between different components
■ Evaluation of electromagnetic radiation from packages and printed circuit boards
■ Evaluation of signal and noise spectrum at various locations
■ Evaluation of signal and noise waveforms at various locations
■ Identification of package resonance.
SPDGEN and SPDSIM
SPEED2000 is composed of two executable modules: SPDGEN and SPDSIM.
■ SPDGEN — Provides a graphical user interface so the user can conveniently build and
modify package components and establish simulation parameters
■ SPDSIM — Provides the transient simulation engine that processes and displays the
package components. SPDSIM also provides a post processing interface so the user can
analyze, compare and print the results of package simulation
The SPDSIM simulations are entirely controlled by what the user establishes and sets up in
the SPDGEN package editor.
SPEED2000 provides powerful 3D editing functions using the SPDGEN module. Before
the.spd file (representing your package) is loaded into the SPDSIM module, the viewing and
simulation parameters need to be specified within the.spd file using the SPDGEN module.
In addition to simulation, the SPDSIM module provides a post processing interface so the
user can analyze, compare, save, export and print the results of package simulation.
■ The SPDGEN module provides the GUI-based package geometry editor and file builder,
it is used to create and edit the SPEED file (.spd) which contains package geometry and
simulation parameters
■ The SPDGEN Graphical User Interface (GUI) makes convenient “what if” analysis of a
package design possible; that is, a user can conveniently engineer a possible solution to
a problem (made apparent during the simulation) then simulate the new model to see the
results of changes made
■ The SPDSIM module loads and executes a transient simulation of the .spd file created
by SPDGEN. It should be noted that SPDSIM does not change the .spd file contents.
Use SPDGEN to select which components of a package design will be simulated
