Inductance-to-digital converter targets high-speed measurement systems

The Texas Instruments LDC1101 inductance-to-digital converter (LDC) is now available from Mouser stock. The 1.8V to 3.3V high-resolution data converter is designed for short-range, high-speed, contactless sensing of position, rotation, or motion. The LDC1101 provides accurate measurements in both controlled and harsh environments, making it ideal for automotive, consumer, industrial, computer, and communications applications. The device features dual inductive measurement cores, allowing for 16-bit resonator resistance (RP) and inductance (L) measurements at more than 150 Ksps. Simultaneously, the converter can perform 24-bit-resolution inductance measurements at more than 180ksps. The LDC1101 includes a threshold-compare function which can be dynamically updated while the device is running, greatly simplifying designs such as high-speed gear counting. The LDC1101 supports a wide range of inductor / capacitor (LC) combinations with oscillation frequencies ranging from 500kHz to 10MHz and RP ranging from 1.25kohm to 90kohm. The device is configured and conversion results retrieved through a simple 4-wire SPI. The only external components necessary for operation are a 15nF capacitor for internal LDO bypassing and supply bypassing for VDD. TI's LDC1101EVM evaluation module, also available from Mouser, allows designers to test and demonstrate inductive sensing technology using the LDC1101 device. The evaluation board includes an example PCB sensor coil that connects to the LDC1101. Designers can use the onboard TI MSP430 microcontroller to interface the LDC to a host computer. This module is designed to provide the user with maximum flexibility for system prototyping.