Op-amps enable I/O full-swing operation at only 1.7V

16th December 2013

Staff Reporter

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Designed for motion sensor applications, the BD5291G and BD5291FVE op-amps from ROHM fulfill the growing demand for incorporating sensors in devices to detect acceleration, angular velocity, and other parameters. The op-amps utilize ROHM’s analog technology, enabling input/output full-swing operation at only 1.7V. In addition, a high common-mode rejection ratio results in a small-signal processing accuracy 18x greater than conventional products.

As can be seen in the chart below, the featured low-voltage input/output full-swing operation is suitable for applications with low-voltage requirements.

Offset voltage generated at the differential input stage is reduced significantly, resulting in a high common-mode rejection ratio (70dB min). This makes it possible to amplify small signals (i.e. from sensors) with greater accuracy. The op-amps provide low voltage operation with I/O full-swing capability and high common-mode rejection ratio (conventionally difficult to achieve all 3), contributing to greater accuracy in small-signal applications such as sensor output. This makes them also well-suited for microphone amps, active filters, buffer amps, amplification circuits, and other applications utilizing opamps.

Following the increasing integration of digital and analog systems in power supplies is lower voltage operation. Unlike conventional input/output full-swing opamps that operate from 1.8V, these products support 1.7V operation, providing sufficient margin against supply voltage fluctuations. In addition, common-mode rejection ratio is 70dB (min), compared to only 45dB (min) with comparable devices, making it possible to provide high-accuracy signal amplification. (CMRR is calculated by dividing the common-mode signal variation with the output voltage variation, with 45dB and 70dB roughly equivalent to 178x and 3,162x, respectively.)