OCH1970VAD-H is a 3D digital-output linear Hall sensor chip designed by OCS specifically for magnetic-axis keyboard applications, featuring ultra-high precision and ultra-low power consumption.

     The circuit design of this chip integrates precision components, including a Hall effect sensor, a chopper circuit, an analog-to-digital conversion (ADC) module, and a communication module. It supports both I2C and SPI—two mainstream communication protocols—while providing precise 16-bit three-axis data output and a wide range of programmable sensitivity settings, thereby meeting high-precision detection requirements in diverse and complex environments.

Faster, more accurate real-time control

     The OCH1970VAD-H features virtual channels that enable configurable magnetic sensor architectures, allowing real-time calibration of performance parameters—including static output voltage, band-gap reference, sensitivity temperature coefficient, internal bias point, and output clamping voltage—thereby laying the foundation for flexible offset cancellation and precision matching of the chip.

     In high-sensitivity mode, OCH1970 achieves a sensitivity of 1.1 μT/LSB with a measurement range of ±36 mT; in wide-range mode, its sensitivity reaches 3.1 μT/LSB, with a measurement range of ±34.9 mT for the XY axes and ±101.5 mT for the Z axis, enabling faster and more accurate detection.

Low power consumption and improved power efficiency

     The device employs techniques such as symmetric layout design, sensitive line-pattern substrate isolation, and digital-to-analog magnetic layout isolation rings to achieve area-efficient layout matching. It operates within a voltage range of 1.7 V to 3.6 V, features a standby power consumption of merely 8 μA, and achieves a response frequency of 200 Hz. Compared to foreign 3D Hall-effect position sensors, this device maintains equivalent system performance while reducing power consumption; it also offers configurable operating modes, enabling power reduction in battery-powered applications or in light-load modes where system efficiency is a priority.

High integration, compact size iterations

     The OCH1970VAD-H features an ultra-compact DFN-8 package. Thanks to its compact footprint, ultra-thin packaging, and extremely low power consumption, this rotational magnetic position sensor integrates both planar and vertical Hall effect technologies to output multi-directional magnetic position sensing data. It provides customers with configurable signal paths to optimize sensing accuracy. The device's high integration capability enables the incorporation of multiple magnetic switch functions onto a single chip, achieving multi-functionality from one chip and contributing to the development of an AI "China Chip".

Technical Advantages of OCH1970VAD-H

     Each of the three axes features a 16-bit digital output, supporting internal programming to implement three-axis switching Hall effect functionality.

     Supports both I2C & SPI communication protocols.

     Programmable switch functionality – 3D Hall effect switch.

     The magnetic field measurement range and sensitivity are selectable.

     High-sensitivity mode: sensitivity 1.1 μT/LSB; measurement range for 3 axes: ±36 mT.

     Wide-range mode: sensitivity 3.1 μT/LSB; measurement range: X/Y: 34.9 mT, Z: 101.5 mT.

     Operating voltage range: 1.7–3.6 V.

     Operating temperature range: -40 °C to +85 °C.

     Standby power consumption: 8 μA.

     Response frequency: 200 Hz (Max).

     Package: DFN-8.

Typical Application – Magnetic Axis Keyboard

The magnetic switch comprises an axle core, a Hall sensor, and a spring. When the button is pressed, the magnet approaches the Hall sensor, inducing a change in the magnetic field; this causes the Hall voltage to exceed a threshold, thereby triggering the corresponding action. Upon release, the magnetic switch again detects a change in the magnetic field.

Unlike traditional mechanical keyboards, magnetic switch keyboards utilize Hall effect technology in their switches, enabling faster and more stable key actuation, as well as enhanced durability and a longer service life.

OCH1970VAD-H is a low-power linear Hall sensor specifically designed for magnetic axis keyboards. Its high-sensitivity mode can detect faint magnetic field changes, with trigger travel adjustable freely from 0.1 mm to 4.0 mm and a precision of up to 0.1 mm; its wide-range mode can detect magnetic fields up to 101.5 mT.

OCH1970VAD-H supports high-speed SPI communication, enabling simultaneous control of multiple buttons with faster response times. Its ultra-compact DFN2030-8 package (nominal height: 0.55 mm) is ideal for space-constrained magnetic axis applications.