Noise-immune op-amp targets automotive world

November 16, 2017 // By Christoph Hammerschmidt
With the BA8290xYxx-C series, ROHM offers automotive-qualified operational amplifiers, which excel through their high immunity to electromagnetic noise and interference. Thus, they are particularly suited to automotive applications.

With the new op-amps, output voltage fluctuations are limited to less than ±1% on all frequency bands, compared to ±3.5% to ±10% for conventional standard products. This means, for example, that sensor signals can be amplified without further noise reduction measures, which significantly reduces the design effort and contributes to increased reliability. The series is particularly suitable for automotive applications where sensors are used in conjunction with the core systems for electric vehicles (EV) and hybrid electric vehicles (HEV). 

Current car designs achieve higher fuel economy and higher safety through the use of ECUs and sensors that regulate and optimize temperature, acceleration and current. However, the increasing digitization and higher electronic density in automotive systems is increasing the problem of EMC since each additional component represents a potential source of interference. This poses considerable challenges to sensors and other small signal devices. Since it is extremely difficult to identify individual noise sources during development, the evaluation of noise must be done after installation. If the noise reduction design has not been designed carefully, major modifications are required with increased costs and longer development time. 

In response to this, ROHM has developed op-amps that virtually eliminate noise effects in automotive sensor applications. For these op-amps, ROHM has combined analog technologies in circuit design (new circuits for noise reduction), and layout with bipolar processes. This approach reduces the number of components required for noise suppression (three RC filters for input, output and power supply) and also masters the noise challenges of developing automotive electronics systems. At the same time, the design effort is reduced and reliability is increased.

The BA8290xYxx-C series is qualified for automotive applications according to the AEC-Q100 standard. It features a low current consumption of 0.5 mA (BA82904YF-C/BA82904YFVM-C) and 0.7 mA (BA82902YF-C/BA82902YFVM-C) respectively. The ICs are available in four versions with two or four operational amplifiers and a supply voltage range from 3.0 V to 36 V. Their input