Achieving high reliability and simplifying mechanical design in switching applications

TI (CEO Kent Tran) announced the launch of the industry's first differential inductive switch product. The new LDC0851 uses a dual-coil architecture to automatically compensate for temperature changes and component aging. Additionally, it can simply detect the presence of conductive objects using a simple coil drawn on a printed circuit board (PCB).

With this unique approach, reliable switching can be implemented at low cost for detecting buttons, knobs, and door opening/closing, as well as speed and direction, in personal electronic devices, home appliances, industrial equipment, and communication applications.


The LDC0851 has a threshold of less than 1% of the sensor coil diameter, providing stable switching accuracy for temperature, eliminating the need for production calibration, and minimizing deviations between devices. Furthermore, unlike other sensor technologies, the LDC0851 is designed as a non-contact, magnet-free device, making it resistant to contamination, dust, and other environmental factors, thereby offering developers a reliable and affordable solution.

In addition to this, TI offers innovative inductive sensor integrated IC products, including the LDC1614 multichannel inductance-to-digital converter family.

This product features a differential architecture that reliably maintains switching thresholds against fluctuations in temperature, humidity, and other environmental factors, and provides stable, long-term performance through resistance to component aging. In addition, it provides a switching accuracy of less than 1%, making it up to 10 times more accurate than magnetic sensor-based designs, so production calibration is not required.

This device is resistant to non-conductive contaminants such as oil, dirt, and dust, extending product lifespan and reducing replacement costs. Additionally, it is unaffected by direct current (DC) magnetic fields, providing robust operation and reliability in various environments. The LDC085 consumes an average current of less than 20uA at 10sps (samples per second) during duty cycling, which is up to five times lower than competing solutions.

Using TI's LDC0851EVM evaluation module, the LDC0851 can be configured more easily and quickly started into a system without programming. The LDC0851EVM is currently available for purchase at the TI store and authorized TI distributors for $20.

The Incremental Rotary Encoder Reference Design (TIDA-00828) provides a simple 32-position rotary knob design using the LDC0851. This system can track rotational position and direction using only two LDC0851 inductive switches, allowing developers to easily increase or decrease the number of encoder positions. Other inductive sensor reference designs can be found in the TI Designs Reference Design Library.

System developers can quickly design inductive sensors using TI's WEBENCH® Coil Designer. By using this online tool, they can easily design based on sensor coils according to application and system requirements. In addition, since the optimized design can be exported to various CAD (computer-aided design) programs, sensor coils can be quickly integrated into the overall system layout.

The 8-pin LDC0851 is currently available in a 2mm x 2mm WSON (very-thin small-outline no-lead) package through the TI store and authorized TI distributors. The price is $0.38 per unit for quantities of 1,000.