Built-in Self Research Articles

A 20 dBm Fully-Integrated 60 GHz SiGe Power Amplifier With Automatic Level Control

A + 20 dBm power amplifier (PA) for applications in the 60 GHz industrial scientific medical (ISM) band is presented. The PA is fabricated in a 0.13-mum SiGe BiCMOS process technology and features a fully-integrated on-chip RMS power detector for automatic level control (ALC), built-in self test and voltage standing wave ratio (VSWR) protection. The single-stage push-pull amplifier uses center-tapped microstrips for a highly efficient and compact layout with a core area of 0.075 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The PA can deliver up to 20 dBm, which to date, is the highest reported output power at mm-wave frequencies in silicon without the need for power combining. At 60 GHz it achieves a peak power gain of 18 dB, a 1-dB compression (P1dB) of 13.1 dBm, and a peak power-added efficiency (PAE) of 12.7%. The amplifier is programmable through a three-wire serial digital interface enabeling an adaptive bias control from a 4-V supply.

RF Built-in Self Test of a Wireless Transmitter

RF frequency synthesizers and transmitters for wireless system-on-chips have recently migrated to low-cost deep-submicrometer CMOS processes that facilitate all-digital implementations. In addition to all the benefits of lower power, lower silicon cost, reduced board area, and improved performance that the scaled CMOS integration entails, the testing costs for RF performance and wireless standard compliance could also be drastically reduced. In this brief, we propose a built-in self test (BIST) method, which is based on the premise that the internal frequency synthesizer and transmitter signals are in digital format allowing for digital signal processing to ascertain the RF performance without external test equipment. With the RF BIST capability, millions of SoCs can be calibrated and tested in a production environment using a low cost digital tester while benefiting from increased test coverage and reduced test time and cost. The presented techniques have been successfully implemented in two generations of commercial digital RF processors: 130-nm Bluetooth and 90-nm GSM single-chip radios

A SIC PAIR GENERATOR FOR A BILBO ENVIRONMENT

Built-In Self Test (BIST) techniques are commonly used as an efficient alternative to external testing in today's high-complexity VLSI chips since they provide on-chip test pattern generation and response verification. Among the BIST techniques, Built-In Logic Block Observation (BILBO) has been widely used in practice. Test patterns generated by BILBO structures target the detection of stuck-at faults. It has been shown that most common failure mechanisms that appear into current CMOS VLSI circuits cannot be modeled as stuck-at faults. These mechanisms, modeled by sequential (i.e., stuck-open and delay) faults models, require the application of two-pattern tests (vector pairs) in the circuit-under-test inputs. Single Input Change (SIC) pairs are pairs of patterns where the second pattern differs from the first in only one bit and have been successfully used for two-pattern testing. In this paper we present the BILBO-oriented SIC pair Generator technique that extends BILBO in order to generate SIC pairs; in this way, sequential faults are also detected.

The First Fully Integrated Quad-Band GSM/GPRS Receiver in a 90-nm Digital CMOS Process

We present the receiver in the first single-chip GSM/GPRS transceiver that incorporates full integration of quad-band receiver, transmitter, memory, power management, dedicated ARM processor and RF built-in self test in a 90-nm digital CMOS process. The architecture uses Nyquist rate direct RF sampling in the receiver and an all-digital phase-locked loop (PLL) for generating the local oscillator (LO). The receive chain uses discrete-time analog signal processing to down-convert, down-sample, filter and analog-to-digital convert the received signal. A feedback loop is provided at the mixer output and can be used to cancel DC-offsets as well to study linearization of the receive chain. The receiver meets a sensitivity of -110 dBm at 60mA in a 1.4-V digital CMOS process in the presence of more than one million digital gates

Combining Scan Test and Built-in Self Test

For digital chips containing functional logic and embedded memories, these are usually tested separately: Scan test is used for testing functional logic; Memory Built-in Self Test (MBIST) is run for embedded memories. A new approach is proposed to exercise scan test and MBIST in parallel in order to reduce production test time and improve stress tests. It requires only small additional logic and allows to simultaneously run both test modes. In general, the approach can be used to control simultaneously scan test and any Built-in Self Test (BIST) providing a simple pass/fail result.

Design and test issues of an FPGA based data acquisition system for medical imaging using PEM

The main aspects of the design and test (D&T) of a reconfigurable architecture for the Data Acquisition Electronics (DAE) system of the Clear-PEM detector are presented in this paper. The application focuses medical imaging using a compact PEM (Positron Emission Mammography) detector with 12288 channels, targeting high sensitivity and spatial resolution. The DAE system processes data frames that come from a front-end (FE) electronics, identifies the relevant data and transfers it to a PC for image processing. The design is supported in a novel D&T methodology, in which hierarchy, modularity and parallelism are extensively exploited to improve design and testability features. Parameterization has also been used to improve design flexibility. Nominal frequency is 100 MHz. The DAE must respond to a data acquisition rate of 1 million relevant events (coincidences) per second, under a total single photon background rate in the detector of 10 MHz. Trigger and data acquisition logic is implemented in eight 4-million, one 2-million and one 1-million gate FPGAs (Xilinx Virtex II). Functional Built-In Self Test (BIST) and Debug features are incorporated in the design to allow on-board FPGA testing and self-testing during product lifetime.

X-masking during logic BIST and its impact on defect coverage

We present a technique for making a circuit ready for logic built-in self test by masking unknown values at its outputs. In order to keep the silicon area cost low, some known bits in output responses are also allowed to be masked. These bits are selected based on a stuck-at n-detection based metric, such that the impact of masking on the defect coverage is minimal. An analysis based on a probabilistic model for resistive short defects indicates that the coverage loss for unmodeled defects is negligible for relatively low values of n.

HIERARCHICAL SELF TEST FOR SOCS INCLUDING LOGIC AND INTERCONNECTS

Systems on a Chip (SoCs) typically consist of several processor devices, embedded memory blocks, application-specific logic blocks and complex interconnects. While embedded memory blocks are mostly equipped with built-in self test (BIST) capabilities, test methods for processors, logic blocks and interconnects are still topics of intensive research. Beyond production testing, SoCs in safety-critical applications also need built-in self test capabilities, which work independently from external control hardware. A HW / SW –based self test scheme can facilitate self test in the field of application making efficient use of structures for production test and can even supplement production test, e.g. for internal interconnects. The paper describes the architecture, cost and limitations.

Algorithm for the generation of SIC pairs and its implementation in a BIST environment

Built-in self test (BIST) techniques provide for on-chip test pattern generation and response verification operations, and therefore constitute an efficient alternative to external testing for the detection of faults appearing in VLSI circuits. Failure mechanisms that commonly appear in high-speed CMOS VLSI circuits cannot be modelled adequately as stuck-at faults. The detection of these faults requires the application of pairs of patterns to the inputs of the circuit under test. Single input change (SIC) pairs are pairs of patterns where the first pattern of each pair differs from the second pattern in exactly one bit. SIC pairs have been proved to be extremely useful for the detection of stuck-open and delay faults. In this paper a novel algorithm for the generation of SIC pairs is presented, termed decoder-based SIC pair generation (DSG) algorithm. An implementation of the DSG algorithm in a BIST environment is also presented. The number of memory elements utilised is the lowest reported in the literature.

Zigzag-HVP: A Cost-effective Technique to Mitigate Soft Errors in Caches with Word-based Access

Error Correction Code (ECC) is widely used to detect and correct soft errors in VLSI caches. Maintaining ECC on a per-word basis, which is preferable in caches with word-based access, is expensive. This paper proposes Zigzag-HVP, a cost-effective technique to detect and correct soft errors in such caches. Zigzag-HVP utilizes horizontal-vertical parity (HVP). HVP maintains the parity of a data array both horizontally and vertically. Basic HVP can detect and correct a single bit error (SBE), but not a multi-bit error (MBE). By dividing the data array into multiple HVP domains and interleaving bits of different domains, a spatial MBE can be converted to multiple SBEs, each of which can be detected and corrected by the corresponding parity domain. Vertical parity updates and error recovery in Zigzag-HVP can be efficiently executed through modifications to the cache data paths, write-buffer, and Built-In Self Test. The evaluation results indicate that the area and power overheads of Zigzag-HVP caches are lower than those of ECC-based ones.

Memory Defect Tolerance Architectures for Nanotechnologies

Memory Built In Self Repair (BISR) is gaining importance since several years. Because defect densities are increasing in future submicron technologies, more advanced solutions may be required for memories to be produced in the upcoming nanometric CMOS process generations. Moreover, this problem will be exacerbated with nanotechnologies, where defect densities are predicted to reach levels of several orders of magnitude higher than in current CMOS technologies. For such defect densities, traditional memory repair is not adequate. This work presents several Built-In Self Repair techniques addressing memories affected by high defect densities as well as an evaluation of the area cost and yield. Statistical fault injection simulations were conducted and the obtained results show that BISR architectures can be used for future high defect technologies, providing close to 100% memory yield, by means of reasonable hardware cost. Thus, the extreme defect densities that many authors predict for nanotechnologies do not represent a show-stopper, at least as concerning memories.

Low Cost BIST for Static and Dynamic Testing of ADCs

This paper presents a low cost test method for the static and dynamic characterization of analog-to-digital converters. The method is suitable for implementation in a SoC environment, as a built-in self test (BIST) solution. In the proposed approach, noise is used as the test signal. Theory of operation and practical results demonstrating the effectiveness of the method for INL, DNL, THD and SINAD characterization are presented. The BIST surface overhead caused by the noise generator is only 7.4% of the ADC total area. The reduced number of data samples required allows a reduction of about 7.5× in test time, in comparison to the histogram method.

Using a Periodic Square Wave Test Signal to Detect Crosstalk Faults

Built-in self test (BIST) scheme simplifies the detection of crosstalk faults in deep-submicron VLSI circuits in the boundary scan environment. The scheme tests for crosstalk faults with a periodic square wave test signal under applied random patterns generated by a linear feedback shift register (LFSR), which is transconfigured from the embedded circuit's boundary scan cells. The scheme simplifies test generation and test application while obviating the fault occurrence timing issue. Experimental results show that coverage for the induced-glitch type of crosstalk fault for large benchmark circuits can easily exceed 90%.

A counter-based pseudo-exhaustive pattern generator for BIST applications

Built-in self test (BIST) has been accepted as an efficient alternative to external testing, since it provides for both test generation and response verification operations, on chip. Pseudo-exhaustive BIST generators provide 100% fault coverage for detectable combinational faults with much fewer test vectors than exhaustive testing. An (n,k) adjacent bit pseudo-exhaustive test set (PETS) is a set of n-bit vectors in which all 2k binary combinations appear to all adjacent k-bit groups of inputs.In this paper a novel, counter-based pseudo-exhaustive BIST generator is presented, termed pseudo-exhaustive counter (PEC). An n-stage PEC can generate (n,k) adjacent bit PETS for any value of k, k<n. This kind of testing is termed Generic pseudo-exhaustive testing. A Generic pseudo-exhaustive generator can be used to pseudo-exhaustively test more than one module. The PEC scheme is then extended to recursively generate all (n,k) adjacent bit pseudo-exhaustive tests sets for k<=n. This kind of testing is termed progressive pseudo-exhaustive testing in the literature; α progressive pseudo-exhaustive generator can pseudo-exhaustively test more than one modules in parallel.Comparisons of PEC with techniques proposed in the literature that can be used for Generic and Progressive pseudo-exhaustive testing reveal that PEC is more effective in terms of both hardware overhead and time required to complete the test.

On High-Quality, Low Energy Built-In Self Test Preparation at RT-Level

Test power requirements for complex components are becoming stringent. The purpose of this paper is to reuse a recently proposed RT (Register Transfer) Level test preparation methodology to drive innovative Low-Energy (LE)/Low-Power (LP) BIST solutions for digital SoC (System on a Chip) embedded cores. RTL test generation is carried out through the definition of a reduced set of partially specified input vectors (masks), leading to a high correlation between multiple detection of RTL faults and single detection of likely physical defects. The methodology is referred as masked-based BIST, or m-BIST. BIST quality is evaluated considering three attributes: test effectiveness (TE), test length (TL) and test power (TP). LE BIST sessions are defined as short test sequences leading to high values of RT-level IFMB metrics and low-level Defects Coverage (DC). The energy and power of the BIST sessions, with and without mask forcing, is computed. It is shown that, by forcing vectors with the RTL masks, short BIST sessions, with low energy and with a comparable (or smaller) average power consumption, as compared to pseudo-random test, are derived. The usefulness of the methodology is ascertained using the VeriDOS simulation environment and modules of the CMUDSP and TORCH ITC'99 benchmark circuits.

組込み自己テストにおけるテストパターン発生回路 (特集 LSI品質の保証のための提案)

組込み自己テストにおけるテストパターン発生回路 (特集 LSI品質の保証のための提案)

A Ring Architecture Strategy for BIST Test Pattern Generation

This paper presents a new effective Built-In Self Test (BIST) scheme that achieves 100% fault coverage with low area overhead, and without any modification of the circuit under test (CUT), i.e., no test point insertion. The set of patterns generated by a pseudo-random pattern generator, e.g. a Linear Feedback Shift Register (LFSR), is transformed into a new set of patterns that provides the desired fault coverage. To transform these patterns, a ring architecture composed by a set of masks is used. During on-chip test pattern generation, each mask is successively selected to map the original pattern sequence into a new test sequence. We describe an efficient algorithm that constructs a ring of masks from the test cubes provided by an automatic test pattern generator (ATPG) tool. Moreover, we show that rings of masks are implemented very easily at low silicon area cost, without requiring any logic synthesis tool; a combinational mapping logic corresponding to the masks is placed between the LFSR and the CUT, together with a looped shift register that acts as a mask selecting circuit. Experimental results are given at the end of the paper, demonstrating the effectiveness of the proposed approach in terms of area overhead, fault coverage and test sequence length. Note that this paper is an extended version of [1].

Design for Consecutive Testability of System-on-a-Chip with Built-In Self Testable Cores

This paper introduces a new concept of testability called consecutive testability and proposes a design-for-testability method for making a given SoC consecutively testable based on integer linear programming problem. For a consecutively testable SoC, testing can be performed as follows. Test patterns of a core are propagated to the core inputs from test pattern sources (implemented either off-chip or on-chip) consecutively at the speed of system clock. Similarly the test responses are propagated to test response sinks (implemented either off-chip or on-chip) from the core outputs consecutively at the speed of system clock. The propagation of test patterns and responses is achieved by using interconnects and consecutive transparency properties of surrounding cores. All interconnects can be tested in a similar fashion. Therefore, it is possible to test not only logic faults but also timing faults that require consecutive application of test patterns at the speed of system clock since the consecutively testable SoC can achieve consecutive application of any test sequence at the speed of system clock.

Hardware Generation of Random Single Input Change Test Sequences

The combination of higher quality requirements and sensitivity of high performance circuits to delay defects has led to an increasing emphasis on delay testing of VLSI circuits. As delay testing using external testers requires expensive ATE, built-in self test (BIST) is an alternative technique that can significantly reduce the test cost. It has been proven that Single Input Change (SIC) test sequences are more effective than classical Multiple Input Change (MIC) test sequences when a high robust delay fault coverage is targeted. It has also been shown that random SIC (RSIC) test sequences achieve a higher fault coverage than random MIC (RMIC) test sequences when both robust and non robust tests are under considerations the experimental results were based on a software generation of RSIC sequences that are easily generated. Obviously, a hardware RSIC generation providing similar results can be obtained. However, this hardware generator must be carefully designed. In this paper, it is explained what are the criteria which must be satisfied for this purpose. A solution is proposed and illustrated with an example. Then, it is shown that a bad result may be obtained if one of these criteria is not satisfied.

Integrated test of interacting controllers and datapaths

In systems consisting of interacting datapaths and controllers and utilizing built-in self test (BIST), the datapaths and controllers are traditionally tested separately by isolating each component from the environment of the system during test. This work facilitates the testing of datapath/controller pairs in an integrated fashion . The key to the approach is the addition of logic to the system that interacts with the existing controller to push the effects of controller faults into the data flow , so that they can be observed at the datapath registers rather than directly at the controller outputs. The result is to reduce the BIST overhead over what is needed if the datapath and controller are tested independently, and to allow a more complete test of the interface between datapath and controller, including the faults that do not manifest themselves in isolation. Fault coverage and overhead results are given for four example circuits.