Noise tolerant op-amps used in electric vehicle core systems

17th November 2017

Lanna Deamer

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With its BA8290xYxx-C series, ROHM is offering automotive-grade op-amps featuring superior noise immunity. The output voltage fluctuations are suppressed in all frequency bands to less than ±1%, compared to ±3.5% to ±10% with conventional products. This allows, for example, sensor signals to be amplified without the need for noise countermeasures, which significantly reduces design load and contributes to greater reliability.

The new series is well suited for automotive applications, where sensors are used along with the core systems for Electric Vehicles (EV) and Hybrid Electric Vehicles (HEV). The latest automotive systems achieve greater fuel economy and safety by using ECUs and sensors that manage and optimise temperature, acceleration and current.

Greater digitalisation and application density in automotive systems however exacerbate the problem of EMC, since each additional component constitutes a potential source of interference. This presents significant problems for sensors and other small-signal devices. Since it is extremely difficult to evaluate individual sources of noise during automotive development, noise evaluation has to be performed after installation.

Unless careful attention is paid to the design of the noise suppression, major modifications (entailing increased costs and development time) may be required if the application fails testing. In response, ROHM has developed the world's first op-amps that eliminate the effects of noise in automotive sensor applications by utilising a vertically integrated production with analogue design technologies and bipolar processes.

First op-amps that eliminate the need for noise countermeasures
ROHM combines its proven analogue technologies in its BA8290xYxx-C series: circuit design (new noise countermeasures circuit), layout (based on market-proven analogue expertise) and bipolar processes. With this approach, ROHM not only reduces the number of components required for noise suppression (three RC filters for input, output and power supply), but also meets noise-related challenges in the development of automotive electrical systems, whilst contributing to lighter design load and higher reliability.

In future, ROHM is also planning on supplying high noise immunity op-amps for the industrial market.

Supports automotive requirements worldwide
The BA8290xYxx-C series is AEC-Q100 qualified for automotive applications. It is characterised by a low current consumption of 0.5mA (BA82904YF-C/BA82904YFVM-C) and/or 0.7mA (BA82902YF-C/BA82902YFVM-C). The ICs are available in four versions with two or four op-amps and a supply voltage range from 3.0V to 36V.

Their input offset voltage is typically around ±2mV and/or a maximum of ±6mV, the input voltage range between V_EE and V_CC-1.5V. The operating temperature range is –40°C to +125°C.

As package versions, SOP8 (BA82904YF), MSOP8 (BA82904YFVM-C), SOP14 (BA82902YF-C) and SSOP-B14 (BA82902YFVM-C) are available. The pin-compatible packages facilitate easy replacement with existing standard products.

Additional applications