Application and Limits of IC and PCB Scanning Methods for Immunity Analysis

Immunity scanning methods can be used to locate sensitive areas on PCBs and ICs. For the analysis of emissions near field scanning is used to determine the local field strength. Both methods have many similarities and differences. For both methods it is difficult to correlate between board level scanning and system level test results as neither method shows the coupling path directly. The paper shows the implementation of an immunity scanning system and analyzes the advantages and limitations of immunity near field scanning

ESD Susceptibility Characterization of an EUT by Using 3D ESD Scanning System

Electrostatic discharges (ESD) can lead to soft-errors (e.g., bit-errors, wrong resets etc.) in digital electronics. The use of lower threshold voltages and faster I/O increases the sensitivity. In the analysis of ESD problems, an exact knowledge of the affected pins and nets is essential for an optimal solution. In this paper, a three dimensional ESD scanning system which has been developed to record the ESD susceptibility map for printed circuit board is presented and the mechanisms that the ESD event couples into the digital devices is studied. The ESD susceptibility of a fast CMOS EUT is characterized by generating the susceptibility map of the EUT. A series of measurements of the noise coupled into a sensitive trace and pin during an ESD soft error event are presented

Frequency-Domain Measurement Method for the Analysis of ESD Generators and Coupling

A method for analyzing electrostatic discharge (ESD) generators and coupling to equipment under test in the frequency domain is proposed. In ESD generators, the pulses are excited by the voltage collapse across relay contacts. The voltage collapse is replaced by one port of a vector network analyer (VNA). All the discrete and structural elements that form the ESD current pulse and the transient fields are excited by the VNA as if they were excited by the voltage collapse. In such a way, the method allows analyzing the current and field-driven linear coupling without having to discharge an ESD generator, eliminating the risk to the circuit and allowing the use of the wider dynamic range of a network analyzer relative to a real-time oscilloscope. The method is applicable to other voltage-collapse-driven tests, such as electrical fast transient, ultrawideband susceptibility testing but requires a linear coupling path

Automated Near-Field Scanning to Identify Resonances

Near-field scanning systems are a tool for rootcause ESD, EMI, and immunity analysis of electronic systems, as well as qualification methodology for ICs and modules. For emissions, they have developed into a standardized method. Development of universally accepted file formats for data exchange is on-going. Four main types of scanning have been implemented by this and other authors: Near-field EMI scanning, ESD scanning, radiated immunity scanning, and resonance scanning. This article concentrates on resonance scanning as a newly added method for automated EMC system analysis

Susceptibility Scanning as Failure Analysis Tool for System-Level Electrostatic Discharge (ESD) Problems

Susceptibility scanning is an increasingly adopted method for root cause analysis of system-level immunity sensitivities. It allows localizing affected nets and integrated circuits (ICs). Further, it can be used to compare the immunity of functionally identical or similar ICs or circuit boards. This paper explains the methodology as applied to electrostatic discharge and provides examples of scan maps and signals probed during immunity scanning. Limitations of present immunity analysis methods are discussed

Susceptibility scanning system as failure analysis tool for system level ESD problems

System level Electrostatic Discharges (ESDs) can lead to soft-errors (e.g., bit-errors, wrong resets). The goal of this project is to offer guidance in finding the root cause of soft-errors frequently observed using immunity scanning system. Immunity scanning is an increasingly adopted method for root cause analysis of system level immunity sensitivities. It allows localizing affected nets and ICs. At first a description of the ESD discharge process is given, which provides the necessary background for correctly analyzing ESD failures. Local scanning and in-circuit measurement techniques are expounded in this study. Further, it is shown how PCB scanning results can reveal local sensitivities, enabling the characterization and optimization of circuit and ICs design, as well as the design of software for minimizing unwanted responses to soft-error causing noise. Further, it can be used to compare the immunity of functionally identical or similar ICs or circuit boards. This thesis explains the methodology as applied to ESD and provides examples of scan maps and signals probed during immunity scanning. Limitations of present immunity analysis methods are discussed. The immunity scanning system developed is described. The thesis contains a description of the hardware components of the system including failure detection solutions for different types of devices under test. The description of developed scanning software including hardware control modules and graphic user interface is given --Abstract, page iii

Finding the Root Cause of an ESD Upset Event

System level Electrostatic Discharges (ESD) can lead to soft-errors (e.g., bit-errors, wrong resets etc.). By this talk we try to offer guidance in finding the root cause of upsets frequently observed in immunity testing (e.g., ESD, EFT). At first a description of the ESD discharge process is given. It provides the necessary background for correctly analyzing ESD failures. Local scanning and in-circuit measurement techniques are explained. Further, it is shown how PCB scanning results, revealing local sensitivities, can be used for the characterization and optimization of circuit and ICs design and software for minimizing unwanted responses to soft-error causing noise. A series of measurements of such noise voltages coupled into a sensitive trace are presented

Effect of Inhomogeneous Medium on Fields Above GCPW PCB for Near-Field Scanning Probe Calibration Application

In this paper, a method is proposed to calibrate a probe by placing it into a known field and referencing its output voltage to the known field. A transmission line is a convenient structure for creating such a known field. This paper presents the effect of the inhomogeneous medium on the near-field generated over a grounded coplanar waveguide (GCPW) printed circuit board (PCB) and reports the field pattern over the GCPW. GCPW PCBs are used to determine the probe factor for near-field scanning applications. A near-field scan is performed to visualize the near-field sources over a device under test (DUT). The near-field is measured by using E- and H-field electromagnetic interference probes. The output of these probes is a voltage and using the probe factor, the field present over the DUT can be determined. To calculate the probe factor, the near-field strength needs to be known using the 3-D simulation. GCPW creates a quasi-TEM field. The effect of non-TEM modes is easily underestimated, such that non-TEM fields prevent the user from determining the unwanted field suppression of probes at higher frequencies

Probe Characterization and Data Process for Current Reconstruction by Near Field Scanning Method

Previously a measurement technique for ESD current spreading on a PCB using near field scanning was developed in order to connect the local ESD sensitivity to system level ESD failures in time and spatial domain. The concept of such scanning methodology is proved and several scanning results were processed. However the validation, precision and weakness of such methodology need to be further investigated before the application of such scanning methodology on complex circuit or system. This article investigates the current reconstruction by near field scanning technique and methodology. It studies the probe factors including coupling frequency response characterization and deconvolution method, spatial resolution for scanning and orthogonal-scan data combine process