Integration of a Digital Built-in Self-Test for On-Chip Memories

The ability of testing on-chip circuitry is extremely essential to ASIC implemen- tations today. However, providing functional tests and verification for on-chip (embedded) memories always poses a huge number of challenges to the designer. Therefore, a co-existing automated built-in self-test block with the Design Under Test (DUT) seems crucial to provide comprehensive, efficient and robust testing features. The target DUT of this thesis project is the state-of-the-arts Ultra Low Power (ULP) dual-port SRAMs designed in ASIC group of EIT department at Lund University. This thesis starts from system RTL modeling and verification from an earlier project, and then goes through ASIC design phase in 28 nm FD-SOI technology from ST-Microelectronics. All scripts during the ASIC design phase are developed in TCL. This design is implemented with multiple power domains (using CPF approach and introducing level-shifters at crossing-points between domains) and multiple clock sources in order to make it possible to perform various measurements with a high reliability on different flavours of a dual-port SRAM.This design is able to reduce dramatically the complexity of verification and measurement to integrated memories. This digital integrated circuit (IC) is developed as an application-specific IC (ASIC) chip for functional verification of integrated memories and measuring them in different aspects such as power consumption. The design is automated and capable of being reconfigured easily in terms of required actions and data for testing on-chip memories. Put it in other words, this design has automated and optimized the generation of what data to be stored on which location on memories as well as how they have been treated and interpreted later on. For instance, it refreshes and delivers different operation modes and working patterns to the entire test system in order to fully utilize integrated memories, of which such an automation is instructed by the stimuli to the chip. Besides, the pattern generation of the stimuli is implemented on MATLAB in an automated way. Due to constant advancements in chip manufacturing technology, more devices are squeezed into the same silicon area. Meaning that in order to monitor more internal signals introduced by the increased complexity of the circuits, more dedicated input/output ports (the physical interface between the chip internal signals and outside world) are required, that makes the chip bonding and testing in the future difficult and time-consuming. Additionally, memories usually have a bigger number of pins for signal reactions than other circuit blocks do, the method of dealing with so many pins should also be taken into account. Thus, a few techniques are adopted in this system to assist the designers deal with all mentioned issues. Once the ASIC chip has been fabricated (manufactured) and bonded, the on-chip memories can be tested directly on a printed circuit board in a simple and flexible way: Once test instruction input is loaded into the chip, the system starts to update the system settings and then to generate the internal configurations(parameters) so that all different operations, modes or instructions related to memory testing are automatically processed

Built-In Self-Test (BIST) for Multi-Threshold NULL Convention Logic (MTNCL) Circuits

This dissertation proposes a Built-In Self-Test (BIST) hardware implementation for Multi-Threshold NULL Convention Logic (MTNCL) circuits. Two different methods are proposed: an area-optimized topology that requires minimal area overhead, and a test-performance-optimized topology that utilizes parallelism and internal hardware to reduce the overall test time through additional controllability points. Furthermore, an automated software flow is proposed to insert, simulate, and analyze an input MTNCL netlist to obtain a desired fault coverage, if possible, through iterative digital and fault simulations. The proposed automated flow is capable of producing both area-optimized and test-performance-optimized BIST circuits and scripts for digital and fault simulation using commercial software that may be utilized to manually verify or adjust further, if desired

In-field Built-in Self-test for Measuring RF Transmitter Power and Gain

abstract: RF transmitter manufacturers go to great extremes and expense to ensure that their product meets the RF output power requirements for which they are designed. Therefore, there is an urgent need for in-field monitoring of output power and gain to bring down the costs of RF transceiver testing and ensure product reliability. Built-in self-test (BIST) techniques can perform such monitoring without the requirement for expensive RF test equipment. In most BIST techniques, on-chip resources, such as peak detectors, power detectors, or envelope detectors are used along with frequency down conversion to analyze the output of the design under test (DUT). However, this conversion circuitry is subject to similar process, voltage, and temperature (PVT) variations as the DUT and affects the measurement accuracy. So, it is important to monitor BIST performance over time, voltage and temperature, such that accurate in-field measurements can be performed. In this research, a multistep BIST solution using only baseband signals for test analysis is presented. An on-chip signal generation circuit, which is robust with respect to time, supply voltage, and temperature variations is used for self-calibration of the BIST system before the DUT measurement. Using mathematical modelling, an analytical expression for the output signal is derived first and then test signals are devised to extract the output power of the DUT. By utilizing a standard 180nm IBM7RF CMOS process, a 2.4GHz low power RF IC incorporated with the proposed BIST circuitry and on-chip test signal source is designed and fabricated. Experimental results are presented, which show this BIST method can monitor the DUT’s output power with +/- 0.35dB accuracy over a 20dB power dynamic range.Dissertation/ThesisMasters Thesis Electrical Engineering 201

Defect-tolerance and testing for configurable nano-crossbars

Moore\u27s Law speculated a trend in computation technology in terms of number of transistors per unit area that would double roughly every two years. Even after 40 years of this prediction, current technologies have been following it successfully. There are however, certain physical limitations of current CMOS that would result in fundamental obstructions to continuation of Moore\u27s Law. Although there is a debate amongst experts on how much time it would take for this to happen, it is certain that some entirely new paradigms for semiconductor electronics would be needed to replace CMOS and to delay the end of Moore\u27s Law. Silicon nanowires (SiNW) and Carbon nanotubes (CNT) possess significant promise to replace current CMOS --Abstract, page iv

A chaotic switched-capacitor circuit for characteristic CMOS noise distributions generation

A switched-capacitor circuit is proposed for the generation of noise resembling the typical noise spectral density of MOS devices. The circuit is based on the combination of two chaotic maps, one generating 1/f noise (hopping map) and the other generating white noise (Bernoulli map). Through a programmable weighted adder stage, the contribution of each map can be controlled and, thereby, the position of the corner frequency. Behavioral models simulations were carried out to prove the correct functionality of the proposed approach.Ministerio de Economía y Competitividad TEC2016-80923-

Design for Testability in a SerDes System

Testing an IC after fabrication helps ensure chip functionality. The techniques that consider the creation and utilization of tests inside the design flow are called Design for Testability. The present work evaluates and improves the test modules implementing BIST techniques created by César Limones 2016 thesis. It is important to mention that this work reports the first effort to make the full SerDes analog and digital module integration at ITESO. It required all the designers to work together in order to complete the SerDes chip design flow. In particular, the comparison data module design structure was redefined after the data flow was analyzed. The test modules simulation demonstrated the correct functionality while the timing reports with a 156.25MHz clock frequency, showed that the design is timing compliant. The SerDes final layout, which also integrated the test modules, was created with the analog modules placement and routing. However, there were issues with the routing over the analog modules, which produced an overlap on the internal metal layers. For this reason, it is encouraged to further research about the association and outcomes between the layout of the analog modules, the LEF file generation, and the analog module routing in the design flowRealizar pruebas en un chip luego de ser fabricado asegura la funcionalidad del circuito integrado. Las técnicas que contemplan la creación y aplicación de pruebas dentro del flujo de diseño del chip se llaman design for testability (diseño testable). Esta tesina evalúa y mejora los módulos de prueba que implementan técnicas de BIST, los cuales fueron creados por César Limones en la tesina del 2016. Es importante mencionar que este trabajo reporta los primeros esfuerzos realizados en el ITESO en integrar los módulos análogos y digitales que componen el SerDes. Se requirió del trabajo conjunto de todos los diseñadores para completar el flujo de diseño del chip del SerDes. En particular, la estructura del módulo de comparación fue totalmente modificada luego de que el flujo de datos fue analizado. Mediante la simulación de los módulos pruebas se demostró su correcto funcionamiento y los reportes de análisis de tiempo aplicados con un reloj a una frecuencia de 156.25MHz, mostraron que el diseño cumple con las restricciones de tiempo. El layout (diseño) final del SerDes, que integra también los módulos de pruebas, fue creado con la colocación y enrutamiento de los módulos análogos. Sin embargo, se presentaron problemas con el enrutamiento creado sobre el módulo análogo lo cual provocó un solapamiento con las capas de metal internas. Por esta razón, se exhorta a investigar sobre la asociación y resultados entre el layout de los módulos análogos, la generación del archivo LEF y el enrutamiento de los módulos análogos en el flujo de diseño.ITESO, A. C.Consejo Nacional de Ciencia y Tecnologí

Area-Delay-Efficeint FPGA Design of 32-bit Euclid's GCD based on Sum of Absolute Difference

Euclids algorithm is widely used in calculating of GCD (Greatest Common Divisor) of two positive numbers. There are various fields where this division is used such as channel coding, cryptography, and error correction codes. This makes the GCD a fundamental algorithm in number theory, so a number of methods have been discovered to efficiently compute it. The main contribution of this paper is to investigate a method that computes the GCD of two 32-bit numbers based on Euclidean algorithm which targets six different Xilinx chips. The complexity of this method that we call Optimized_GCDSAD is achieved by utilizing Sum of Absolute Difference (SAD) block which is based on a fast carry-out generation function. The efficiency of the proposed architecture is evaluated based on criteria such as time (latency), area delay product (ADP) and space (slice number) complexity. The VHDL codes of these architectures have been implemented and synthesized through ISE 14.7. A detailed comparative analysis indicates that the proposed Optimized_GCDSAD method based on SAD block outperforms previously known results

From FPGA to ASIC: A RISC-V processor experience

This work document a correct design flow using these tools in the Lagarto RISC- V Processor and the RTL design considerations that must be taken into account, to move from a design for FPGA to design for ASIC

Scalable algorithms for software based self test using formal methods

textTransistor scaling has kept up with Moore's law with a doubling of the number of transistors on a chip. More logic on a chip means more opportunities for manufacturing defects to slip in. This, in turn, has made processor testing after manufacturing a significant challenge. At-speed functional testing, being completely non-intrusive, has been seen as the ideal way of testing chips. However for processor testing, generating instruction level tests for covering all faults is a challenge given the issue of scalability. Data-path faults are relatively easier to control and observe compared to control-path faults. In this research we present a novel method to generate instruction level tests for hard to detect control-path faults in a processor. We initially map the gate level stuck-at fault to the Register Transfer Level (RTL) and build an equivalent faulty RTL model. The fault activation and propagation constraints are captured using Control and Data Flow Graphs of the RTL as a Liner Temporal Logic (LTL) property. This LTL property is then negated and given to a Bounded Model Checker based on a Bit-Vector Satisfiability Module Theories (SMT) solver. From the counter-example to the property we can extract a sequence of instructions that activates the gate level fault and propagates the fault effect to one of the observable points in the design. Other than the user supplying instruction constraints, this approach is completely automatic and does not require any manual intervention. Not all the design behaviors are required to generate a test for a fault. We use this insight to scale our previous methodology further. Underapproximations are design abstractions that only capture a subset of the original design behaviors. The use of RTL for test generation affords us two types of under-approximations: bit-width reduction and operator approximation. These are abstractions that perform reductions based on semantics of the RTL design. We also explore structural reductions of the RTL, called path based search, where we search through error propagation paths incrementally. This approach increases the size of the test generation problem step by step. In this way the SMT solver searches through the state space piecewise rather than doing the entire search at once. Experimental results show that our methods are robust and scalable for generating functional tests for hard to detect faults.Electrical and Computer Engineerin