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Operational Amplifiers for Automotive Application from STMicroelectronics

Created by Thomas Bolz |   Knowledge

Operational amplifiers can be used in a wide range of applications – including motor vehicles. However, not all suppliers meet the high requirements placed on these components.

To save space and weight, car components are usually positioned very close to their functional units. This means they frequently have to withstand temperatures of up to 150°C. Furthermore, space-saving packages such as DFN, QFN or MiniSO are in demand. What is always of paramount importance is adherence to standards AEC Q100 and Q101 as well as test methods in accordance with Q001 "Guidelines for Part Average Testing" (PAT) for EWS (Electrical Wafer Sorting) and Q002 "Guidelines for Statistical Yield Analysis" (SYA). Regulations sometimes demand screening and test methods that go beyond AEC Q100, e.g. 100% thermal stability testing at 125°C during a later stage of production, usually when packaging and testing products.

Moreover, the supplier must be certified to ISO/TS 16949. A key element of the standard is the production part approval process (PPAP), which aims to guarantee the quality of standard parts through a sampling approach. STMicroelectronics not only meets all these requirements but also manages to provide the ideal solution for each application thanks to its wide range of operational amplifiers.


Extensive testing ensures quality

To guarantee high part quality, ST uses in-house equipment to perform high-level parametric tests from very low to very high currents and voltages. Further, there is a 100% electric test featuring extensive test coverage that is additionally combined with an automated optical inspection. The supplier carries out further testing to be able to reject parts which passed initial tests but which may demonstrate flaws in their reliability; a thermal stability test, a junction verification test (JVT), and a final test. Product development as well as testing and other quality processes are based on the experience that ST has gained from years of cooperation with various Tier1 suppliers.


Guaranteed greater comfort

ST offers an extensive portfolio of automotive-qualified power operational amplifiers, ranging from standard amplifiers to high speed, high drive, low power, low noise, and high precision models. They can be integrated quickly and easily into signal processing. In conjunction with automotive sensors, they can increase safety and security while enhancing driver comfort. A few examples:

  • The TSX564IYPT with a typical output current of 90mA is ideal for driving coils of the steering angle sensor or the EPS. It is available in a DFN8 package and a QFN16 package measuring just 2x2mm2 and 3x3mm2 respectively.

  • In terms of the low side current sensing for motor control, the TSZ124IYPT allows you to reduce the resistance value and thus the costs for the shunt thanks to low input offset voltages of less than 5µV at 25°C.

  • For selective catalytic reduction (SCR), the NOx sensor requires an operational amplifier such as the TSV912HYDT with an extremely wide operating temperature range of between -40 and 150°C. It has a low operating voltage and additionally offers an outstanding speed/power input ratio with an 8 kHz gain bandwidth, consuming just 1.1mA at 5V. "It is therefore ideally suited as, e.g., an anti-crushing device of the window lifter in the vehicle. In this scenario, the motor current is measured by a shunt resistor and converted into voltage by the operational amplifier. If the window is stopped, the current increases along with the voltage. Using a voltage comparison method, the control unit is able to respond," says Bolz.

  • The series S922 and TS922A with low noise characteristics (9nV/√ Hz) are recommended to guarantee a high-quality audio signal. They also display very low values in terms of distortion and offset. The rail-to-rail dual BiCMOS operational amplifiers are optimized and specified for 3V and 5V operation. Thanks to their high output currents they enable low load impedances.

  • The series TSV630 and TSV631 are ideal in combination with rain and light sensors. With a low input bias current of less than 10pA at 25°C, or less than 100pA at 125°C, they offer exceptional accuracy without impacting the diode current. Seeing as they additionally provide a low offset voltage, they are also suitable for other applications that demand a high level of precision.

The Automotive Op Amps Sample Kit from ST is available from Rutronik and comes with assistance provided by the Technical Support department. Furthermore, for these applications - and many others besides - Rutronik delivers not only operational amplifiers but also special sensors and microcontrollers. The distributor is thus able to provide customers with perfectly coordinated solutions.


Automotive solutions and automotive support

The Rutronik Automotive Business Unit (ABU) has put together twelve of the best and most renowned suppliers for its automotive customers. The ABU product engineers and FAEs offer their specialist and market expertise to help customers make the right choice. Thanks to membership in the network of Tier1 and Tier2 automotive suppliers run by PGUB Management Consultants GmbH, the experts at the Rutronik ABU are well aware of the current market situation, trends, and highlights. Moreover, they work closely with component suppliers, meaning they have extensive knowledge of the individual components and the roadmaps of suppliers. Rutronik's consultancy approach is, nonetheless, 'supplier neutral'; in other words, several product alternatives are offered for the same function, whenever possible. In addition, the ABU also supports customers when they require additional capacities for development and production. To do so, Rutronik has built up a network of engineer service providers for hardware and software development and contract manufacturers for large scale production. This means: From operational amplifiers and other components to overall solutions and the development and manufacture of products, Rutronik ABU is always the right address for customers!