A test solution based on multi-functional mixed-signal pins

Different from the improvement of the mechanical system in the past that determines the innovation of the automobile industry, 90% of the innovation of the next generation of automobiles comes from more complex integrated circuits. Semiconductor devices play a very important role in meeting customer demand for automotive functions.

    According to Frost&Sullivan's data, the automotive semiconductor market in Western Europe will nearly double in the next few years. The shift of electronic devices originally used in high-end cars to low-end cars is one of the reasons for this rapid growth.

    The electronic system of a modern automobile is a highly distributed real-time system. It consists of a control unit composed of more than 300 motors or solenoid valves connected to up to five bus systems. The system has 100MB of embedded code to provide a power system , Safety, comfort, information and communication functions.

    Power transmission regulates fuel consumption and emissions. Car manufacturers declared that one of their goals is to produce three-liter cars that comply with Euro 3 standards and the Kyoto Protocol. Without the support of electronic devices and software, it is impossible to achieve strict control regulations.

    Therefore, these technical methods are gradually being applied to hybrid generators or vehicles using fuel cells. Another trend is that diesel-powered cars gradually replace gasoline-powered cars.

    The safety and comfort of automobiles have become more and more important. The market's demand for the safety of riding cars is increasing. Automobile manufacturers have already taken measures to this end. At the same time, various technologies, such as anti-lock braking systems or airbags, have become standard configurations for many small and medium-sized vehicles.

    Various technologies such as electronic stability programs or traction control systems have entered the end car market, and it is only a matter of time before it enters the low end cars.

    By implementing a variety of new applications to enhance the comfort of cars, such as keyless entry, seat control, interior environment control or navigation control, automakers strive to provide products that are different from their competitors to gain a competitive advantage.

    It is foreseeable that further market demand will come from communication and information networks in automobiles. People expect their cars to receive broadcast, video, mobile communications, navigation systems, and digital audio/video broadcasts.

    Remote traffic control and services can also be realized in the near future.

    The 42V power grid has become the focus of discussion in recent years. Although every automotive semiconductor supplier can already provide 42V compatible products, there are still disputes over the timing of product introduction and mass production. It can be clearly foreseen that the 42V power supply network will definitely come. According to data provided by Frost&Sullivan, half of the new cars produced by 2015 will use 42 V power supply network technology.

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    Figure 1. In the future, more than 90% of automotive innovation will be driven mainly by electronic devices and software.

    Test challenge

    The main consideration for ATE manufacturers is that the voltage on VBAT must be kept below a certain limit (usually 68 V). Within this voltage limit, the car does not need further protection measures to prevent the high voltage from causing danger to people. The car is "low voltage", this also applies to the 42V power supply network, the voltage must not exceed 68V.

    The other case is the "negative battery". This kind of situation is difficult to deal with for 42V cars, because the voltage is tripled and the voltage cannot be lowered below -2V, so even cars with 42V power supply networks are still in a low voltage modulation state. Obviously the 42 V power supply network cannot drive large negative voltages, but it increases the demand for VI channels that can provide 42 V/80 V voltages.

    In addition, the automotive bus system needs to depress digital pins for functional testing, and the voltage requirement is up to 20 V. Test equipment manufacturers have to take this into consideration.

    Competition in the automotive market in terms of price and quality is becoming increasingly fierce. This means that semiconductor manufacturers have to find high-performance, cost-effective and low-cost test solutions to reduce production costs and ensure that the profit margin is maintained at a certain level.

    The development trend of automotive devices is to integrate various technologies in a single chip, package or module, which is the so-called "system on a chip." Sensors are becoming more and more important. They are used in safety systems such as airbags, driving controls or car power systems.

    The rapid growth of the market over the past 10 years has set severe challenges in achieving quality, time to market, and cost targets. Therefore, the design process of automotive electronics is a key factor for the success of future automotive projects. The life cycle of automotive electronics is very important for semiconductor manufacturers. The development process (including the usual redesign) takes 12-36 months. The car model changes every 6 to 8 years, but the replacement cycle of the electronic devices it uses is only 2 to 4 years. The product use time is less than 10 years. Therefore, with the adoption of new technologies, electronic devices may change faster, while at the same time creating a competitive advantage for automakers.

    The severe challenges faced by the design and testing of automotive devices are requirements in terms of yield and failure rate. The failure rate of mobile phones is allowed to reach 0.5%, while the failure rate of automotive devices must be less than 0.005%. The test requirements for new devices even exceed the following requirements: ASIC failure rate must be less than 0.0003%, standard device failure rate must be less than 0.0001%, and discrete device failure rate must not exceed 0.00005%.

    In order to manage the increasing design complexity and maintain the economics of design work, complex design and test tools must support parallel and distributed specifications, design, implementation, integration, and test work and test solutions.

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    Figure 2. Semiconductor devices operate at 14 V and 42 V voltages, respectively.

    Test solution

    The complexity of the device requires an ATE system with performance and flexibility, but at the same time, productivity must be increased to maintain profit margins and make profits. To achieve this goal, parallel testing of chips must be used, so that productivity can be increased and testing costs can be reduced. The time to create a new application must be as short as possible to match the generation and maintenance of the new test program.

    For mixed-signal test systems for automotive devices, the challenge is to provide digital, analog, DSP, and power supply test capabilities in a comprehensive and cost-effective solution. The system structure must be extensible to cover a wide range of test requirements for automotive electronic products. Flexibility and speed can be achieved through the structure of a real per-pin tester. The high-speed system bus must provide high capacity and high test cost. The performance instrument must be able to fully synchronize with the digital graphics. The electronic performance of the mixed signal tube must be able to support a data transfer rate of up to 50 MHz and provide a voltage swing of -2 V to +28 V.

    Credence's complex power mixed-signal test systems Falcon and Piranha can meet these challenges.

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    Figure 3. Three different pin types cover a wide range of test requirements:

    -DPIN: Digital mixed signal pin, used for high-speed digital requirements;

    -VPIN: A digital mixed-signal pin with voltage test capability. Its 30 V voltage swing and 50 MHz data rate meet the test requirements of automotive devices well;

    -APIN: Analog mixed signal pin, used for pressure, providing +-100 V/40 mA per pin parameter measurement unit (PMU) for power mixed signal testing in the automotive industry.

    Figure 4. Multi-function mixed-signal pin structure diagram.

    Multifunctional mixed signal tube

    Foot electronic performance

    The multifunctional mixed signal pin VPIN includes several functional modules, such as vector memory, ATE pin controller, driver, comparator, load, and independent PMU for each channel.

    The controller is composed of sequence generator, timing generator, formatting device and comparison logic. The digital matrix provides interfaces for connecting digital instruments, such as timers, counters, time measurement units, and triggers for synchronization and triggering.

    Through the analog matrix, each pin channel can use analog instruments, such as VI sources, system voltmeters and DSP instruments. By writing software, the design of the load board and the integration of additional test and measurement circuits can be simplified. The on-board controller allows parallel measurements. The driving/feedback technology guarantees the analog stimulus and allows the use of VPIN in split mode, which can double the test pin channel. Split mode allows the drive and detection paths to be in the same direction.

    The new digital pin VPIN is designed to meet the special test requirements of automotive devices, and the voltage needs to reach 25V (usually 14V) for force testing. VPIN is a mixed signal pin with good digital test performance. It provides a voltage swing of 30V and a data rate of 50MHz for testing voltage-speed mixed-signal devices.

    The true per-pin tester structure provides flexibility and complete parallel testing capabilities. The independent sequence generation for each pin allows synchronous or asynchronous digital patterns to be generated at different data frequencies.

    The vector memory stores test vectors, sequence instructions, format and timing information. The memory contains stimulus/expected data to verify the output data of the device. Transmit and receive memory supports real-time recording, which is required for ADC testing. The data in the memory can be read while the vector is running. The independent PMU for each pin allows parallel DC parameter testing. Through software control line switching, each channel can be connected to analog and digital instruments. The on-board controller stores different test settings, which can be called in parallel so that tests can be executed quickly. The controller can be turned off to reduce noise during analog measurement. The drive/feedback structure guarantees advanced simulation.

    The Credence Falcon system has up to 128 VPIN pins.

    Figure 5. Multi-function mixed signal pin.

    Important instrument

    VI source

    You can choose the performance VI source to cover the testing needs of a wide range of automotive applications. The operation of the VI source can range from low current to power consumption. All sources are floating and can be operated in four quadrants. The on-board measurement supports parallel testing, and the VI can be controlled and triggered by the test vector. Reliability can be obtained through alarm and protection functions. Many other features, such as the superposition and parallel use of VI sources, ensure that users can obtain performance and flexibility.

    Figure 6, V/I source-flexibility from nA to kW.

    DSP generator and digitizer

    Credence’s Falcon and Piranha systems provide several DSP instrument options with a resolution of up to 20 bits and a sampling frequency of up to 200 MHz. DSP generators and digitizers can meet the testing needs of a wide range of analog waveforms of automotive devices. Each DSP instrument has a dedicated DSP engine, which can provide true parallel testing capabilities. Each channel's independent digitizer DSP engine provides fast measurement in time domain or frequency domain. All digitizers and DSP generators can be synchronized with the relevant samples provided.

    System bus

    The embedded synchronization bus ensures the synchronization between all instruments in the system. The synchronization of digital, analog, DSP and power supply instruments can be carried out smoothly. Using the trigger line to trigger the occurrence and measurement of the synchronization signal can easily measure the key time parameters. These unique synchronization capabilities ensure the flexibility and productivity of the system.

    In general, Falcon and Piranha are a flexible solution for the challenges of mixed-signal testing of automotive devices. According to needs, the Credence test system can meet the needs of digital, analog, DSP and power supply testing of devices used in the automotive industry. Through rapid instrumentation and parallel testing technology, Credence's system can provide high throughput and high test cost. The structure and interconnection of each pin tester guarantees flexibility. The advanced software toolkit provides integrated tools to obtain short development-to-production time.