Rohm’s Automotive Hall ICs Offer ‘Industry-Leading Withstand Voltage’
Rohm has devised a new unipolar and latch Hall-effect sensor to better detect magnetic fields in automotive designs.
As the automotive industry undergoes a transformative shift towards electrification and automation, the role of advanced sensor technologies has become increasingly pivotal. Recently, Rohm Semiconductor made additions to this marketplace with the release of two new families of automotive-qualified, Hall-effect sensor ICs.
Rohm has released unipolar and latch Hall ICs for automotive design. Image (modified) used courtesy of Rohm Semiconductor
In this piece, we’ll look at the new chips, what makes them unique from other offerings, and how the two differ from one another.
New Hall ICs Feature 'Industry-Leading' 42 V Withstand Voltage
Rohm's new automotive-grade Hall ICs, the BD5310xG-CZ and BD5410xG-CZ series (datasheets linked), are engineered to meet the growing demands of modern vehicles, which are increasingly reliant on electronic control units (ECUs) and sensors for enhanced functionality, safety, and comfort.
The major feature of these new ICs is their 42 V withstand voltage. This high voltage tolerance enables the device to be directly connected to a vehicle's primary 12 V battery power supply, thereby enhancing reliability, especially when the battery voltage can be subject to rapid fluctuations. According to Rohm, the new IC families mark the industry’s highest Hall-effect withstand voltage.
Block diagram of the BD310xG-CZ devices. Image used courtesy of Rohm Semiconductor
Another noteworthy aspect of the new devices is their wide output voltage range of 2.7 V to 38 V. This makes these Hall ICs versatile enough for a broad array of automotive applications, ranging from low-power sensors to high-power motor controls. The ICs also feature a low current consumption of 1.9 mA (typ), which is approximately 20% lower than general products in the market. This efficiency is particularly beneficial in battery-operated systems, contributing to the vehicle's overall electrical efficiency.
The major difference between the two families is that the BD5310xG-CZ series is an S-pole, detection-type Hall IC, meaning it offers unipolar magnetic detection, while the BD5410xG-CZ series provides latch-type magnetic detection. Because of this, the BD5310xG-CZ is more suited for applications like door locks and open/close detection, and the BD5410xG-CZ family is designed for rotation detection in motors, power windows, and sliding doors.
Unipolar vs. Latch Hall-Effect ICs
Unipolar Hall-effect ICs generate an output signal when a magnetic field is present. The moment the magnetic field disappears, these ICs deactivate.
A latch-type, Hall-effect sensor. Image used courtesy of Digi-Key
In contrast, latch-type, Hall-effect ICs toggle their output state based on the presence and absence of a magnetic field. Latch Hall ICs are commonly used in more complex applications that must detect rotational position, like in electric motors or encoders. Unlike unipolar ICs, latch-type ICs retain their activated state even after the magnetic field is removed and only revert to their original state when exposed to a magnetic field of the opposite polarity.
The primary distinction between the two lies in state retention and application complexity. Latch-type ICs are more complex because they need to detect changes in magnetic field polarity and are often used in applications that require a nuanced understanding of position or rotation. Unipolar ICs, the simpler alternative, merely detect the presence or absence of a magnetic field. Therefore, the choice between unipolar and latch-type Hall-effect ICs is largely dictated by the specific needs of the application.
Between the two new series of devices, Rohm offers 11 models of automotive-qualified devices in detection densities ranging from 2.0 mT to 28.0 mT. Rohm intends to expand this lineup in the future.