Signal integrity (SI) power integrity (PI) learning notes (I) introduction to signal integrity analysis

Introduction to signal integrity analysis
1. Signal integrity （SI）： Refers to all problems caused by interconnection lines in high-speed products ; When the interconnection line interacts with the voltage and current waveform of the digital signal , How its electrical characteristics affect product performance ,SI Also called signal waveform distortion .
2. Power integrity （PI）： Refers to the noise on the interconnection lines and related components that supply power to active devices ;PDN（ Power distribution network ）
3. Electromagnetic compatibility （EMC）： It mainly refers to the electromagnetic radiation generated by the product itself and the electromagnetic interference introduced into the product from the external field ; Generally speaking, electromagnetic compatibility is discussed , When we discuss the problem of radiation, we say electromagnetic interference （EMI）.

4. crosstalk ： When transmitting signals , Some voltages and currents can be transferred to adjacent static networks , And the network is dealing with its own affairs .
5. Rail Collapse ： When the current passing through the power path and the ground path changes , For example, when the chip output is flipped or the gate in the kernel is flipped , A voltage drop is generated on the impedance between the power path and the ground path .
6. electromagnetic interference （EMI）： Electromagnetic interference includes three aspects ： Noise source 、 Radiation propagation path and antenna .
7.SI、PI、EMI Six key types
（1） Signal distortion in a single network ;
（2） Rising edge degradation caused by frequency dependent losses in interconnection lines ;
（3） Crosstalk between two or more networks ;
（4） As a special form of crosstalk, ground bombs and power bombs ;
（5） Track collapse in power and ground distribution ;
（6） Electromagnetic interference and radiation from the whole system .
8. Two corollaries of signal integrity ： First, as the rising edge decreases , These six problems will become more serious ; Second, the effective way to solve the signal integrity is largely based on the understanding of the impedance of the interconnection line .
9. Simulation ： Three electrical simulation tools
（1） Electromagnetic simulator or 3D Full wave field solver
（2） Circuit simulator
（3） Numerical simulation tools

10. Model and modeling
（1）SPICE, By solving the differential equations expressed by circuit elements , Then calculate the voltage and current in time domain or frequency domain , This process is called transient simulation in time domain , It is called AC simulation in frequency domain .
（2）IBIS: Input / Output buffer interface features , The output is V-I or V-T
（3） Three measurement techniques ：① Impedance analyzer ② Vector network analyzer VNA The output impedance of vector network is generally 50Ω
③ Time domain reflectometer TDR
11. Create circuit model through calculation ：
（1） Rule of thumb
（2） Analytical approximation
（3） numerical simulation
12. The relationship between the rising edge and the clock frequency is approximately
RT =0.1Tclock
among ： RT： Indicates rising edge , Unit is ns. Tclock : The clock period , Company ns

13. High frequency or high speed fields ： The clock frequency exceeds 100MHz Or the rising edge is less than 1ns.

14. Power and signal integrity ,checklist,6 Key types
Termination matching inductance noise Parasitic parameters IR Pressure drop radiation crosstalk attenuation Ground bomb Rail Collapse Reflection Down and over Rising edge degradation Impedance mutation Ring the bell Line delay RC Time delay Return current path . wait