October 29, 2019
Expands on ROHM’s EMARMOUR™ series, enables high reliability and simpler designs of automotive systems
ROHM has announced the development of the BA8290xYxxx-C series of ground sense comparators delivering breakthrough tolerance against EMI (noise resistance,) ideal for sensor applications in automotive systems such as ECUs and powertrain.
New advancements in computerization and increase of densely packed electric devices have increased the amount of noise in electric vehicles and cars equipped with Advanced Driver Assistance Systems (ADAS). However, evaluation of noise performance of individual boards and systems, and implementing measures against noise are not feasible in isolation during the development phase. This evaluation and measure implementation need to be done after the whole car has been assembled, making the process of optimization against noise a very lengthy and costly process that might require several iterations.
In response, in 2017 ROHM developed Operational Amplifiers using EMARMOUR™, a proprietary technology that features superior noise tolerance and helps to reduce design resources to implement measures against noise. These devices have been well received by automotive manufacturers. To further meet market needs, today ROHM is introducing the first ultra-high noise-tolerant comparators that use the same breakthrough technology.
This series has achieved superior noise tolerance when used as comparators to determine the threshold value of sensor output signals. It ensures an output voltage fluctuation within ±1% across the entire noise frequency band when testing according to the ISO11452-2 standard. Conventional comparators usually have output voltage fluctuations of up to ±20% due to noise, which can lead to malfunctions (High/Low inverted). In contrast, ROHM’s new series is not susceptible to noise, providing greater reliability while reducing system design man-hours by reducing the amount of time needed for noise evaluation and measure implementation that typically require the use of external filters.
ROHM will offer these new comparators as one of the EMARMOUR™ series. ROHM is committed to enabling even simpler designs and greater reliability in automotive systems by expanding this high noise-tolerant technology to other power supply ICs from ROHM.
What is EMARMOUR™?
EMARMOUR™ is the brand name given to ROHM products developed by leveraging proprietary technologies covering chip layout, processes, and circuit design to achieve ultra-high noise immunity that limits output voltage fluctuation to within ±3% across the entire noise frequency band when testing according to the ISO11452-2 standard. This unprecedented noise immunity reduces design resources and time while improving reliability by solving issues related to noise in the development of vehicle electrical systems.
1. Groundbreaking noise tolerance reduces design resources and time
In contrast to conventional products whose output voltage can fluctuate up to ±20%, the BA8290xYxx-C series utilizes superior noise tolerance to limit output voltage fluctuation to within ±1%, preventing malfunctions. This enables reduction of design resources and time for noise characterization and measure implementation that plays an important role in automotive systems design while improving reliability.
2. Decreasing the number of noise suppression components
Superior noise tolerance eliminates the need for external components used in noise countermeasures (CR filters for the power supply, input, and output pins) used with conventional products. For example, in the case of a 4ch comparator, ROHM’s new products require 28 fewer components than conventional solutions.
3. Meeting international automotive requirements
The BA8290xYxxx-C series is qualified under the automotive reliability standard AEC-Q100 and reduces both current consumption (0.6mA vs 0.8mA) and offset voltage (±5mV vs ±7mV) compared to conventional products. Furthermore, a broad lineup is offered in a variety of common surface mount packages and channel counts with standard comparator pin layout, making it easy to replace existing products in applications sensitive to noise.
EMARMOUR™ Series Featuring Ultra-High Noise Immunity
- EV/HEV inverters
- Automatic transmissions
- Electric power steering
- Automotive lamps
- Combination switches
- EV chargers
- Car navigation
- Vehicle AC
- and other onboard electrical systems sensitive to noise
EMI (Electromagnetic Interference) Tolerance
EMI tolerance is a parameter indicating the degree of tolerance to ambient noise. Noise generated in the environment can cause malfunctions in systems with low EMI tolerance, making it necessary to take protective measures such as incorporating filters (i.e. resistors/capacitors) or shields (metal plates). In contrast, high EMI tolerance ensures stable operation without worrying about the effects of noise, providing a significant advantage by eliminating the design load for noise countermeasures.
Op Amps / Comparators
Op amps (operational amplifiers) are often used to amplify minute signals, such as those output from sensors, to a voltage level that can be recognized by an MCU. Comparators are commonly employed to determine the threshold value of input signals. They output a High/Low signal after performing threshold judgment of the sensor output signal.