ROHM launches first high-speed op amp that eliminates oscillation

ROHM recently announced a high-speed ground sense CMOS op amp, BD77501G, optimized for industrial and consumer equipment requiring high-speed sensing, such as anomaly detection systems used in measurement and control equipment along with sensors that work with very small signals.

The proliferation of IoT in recent years has led to a significant increase in the number of electronic components used for advanced control in a variety of automotive and industrial applications. Among these, op amps are used and are capable of quickly amplifying minute sensor signals in anomaly detection systems that provide safety.

However, board design can become problematic as conventional high-speed op amps are susceptible to oscillation due to capacitive loads (i.e. from wiring). At the same time, degradation of the noise environment resulting from increased electrification and mounting density is making it extremely difficult to implement noise design for small-signal devices.

In response, ROHM developed the EMARMOUR series of op amps and comparators*1 that have been well-received in the automotive and industrial markets due to its superior noise immunity that allows users to reduce design resources to address noise issues. This time, ROHM has expanded the lineup by adding a new high-speed type ideal for anomaly detection that prevents oscillation over the entire load capacitance range.

The BD77501G is the industry’s first op amp that not only supports high-speed amplification (high slew rate: 10V/us) required in anomaly detection and other systems, but also completely eliminates oscillation caused by load capacitance (i.e. wiring). Unlike conventional high-speed op amps that can become unstable due to load-capacitance-induced oscillation, ROHM’s new product ensures stable operation with no unwanted oscillation. In addition, whereas the output voltage for conventional products can fluctuate by ±200mV or more across the entire noise frequency band, the BD77501G provides unprecedented EMI Immunity*2 (noise immunity) that limits variation to less than ±20mV (1/10th).

This enables high-speed signal amplification without being affected by load capacitance or external noise when installed in the latter stages of sensor applications, improving reliability and reducing design time.

ROHM is committed to expand the lineup of this product to automotive market in the near future.

What is EMARMOUR?
EMARMOUR is ROHM’s unique brand to identify its products that leverage proprietary technologies covering circuit design, layout, and processes to achieve ultra-high noise immunity. This technology limits output voltage fluctuation to less than ±300mV across the entire noise frequency band during noise evaluation testing under the international ISO11452-2 standard. This unprecedented noise immunity reduces design resources while improving reliability by solving issues related to noise in the development of a variety of systems.

View the key features here.