Inductive sensor interface ICs use ‘LVDT-on-a-PCB’ principle

December 09, 2015 // By Graham Prophet
Microsemi has to its recently launched family of sensor interface integrated circuits (ICs) based upon inductive sensing technology, with the LX3302.

An addition to the inductive sensor interface IC product family that use linear variable differential transformer (LVDT) architecture implementations on printed circuit boards (PCB), Microsemi's LX3302 is specially designed for applications within the automotive, industrial and commercial aviation markets.

LX3302 improves the LX3301A with an extended temperature range to 150C, and a richer set of system interfaces which include analogue sine/cosine outputs, single edge nibble transmission (SENT) and Peripheral Sensor Interfaces (PSI5), as well as the standard analogue output and pulse width modulated (PWM) output. It has double the EEPROM available in the LX3301A, allowing for eight-point calibration, versus six-point calibration, which increases system accuracy by 1-bit and permits less precise, lower cost sensor manufacturing. The new device features LVDT principles, resulting in superior immunity to noise and interference.

As sensors are the key element in the feedback loop of virtually all closed loop systems, the LX3302 is ideal for a variety of applications related to control systems and industrial automation, including linear displacement measurement (fluid level sensing, gear position for transmission actuator position and brake lamp switch/proximity detection) and angular motion measurement (robotic arm position, rotating shaft position, pedal position and rotary controls). It also meets strict automotive application requirements, including AECQ100-certified grade 0, and comes with Production Part Approval Process (PPAP) documentation support.

Features include:

• Contactless sensing, ensuring high reliability

• Internal temperature sensor

• -40 to 150C operating temperature/qualified to AEC-Q100 grade 0

• Embedded pre-programmed, configurable microcontroller

• Integrated oscillator and demodulator

• Two independent sensor input channels with 13-bit analogue-to-digital converters (ADCs)

• Programmable sample rates to 2 kHz

• Input EMI filters

• 32 x 16 words of user programmable configuration EEPROM

• Built-in diagnostics and ISO26262 compliance

• Outputs: 0 to 5V analogue, PWM, analogue sine/cosine, serial interfaces (SENT and PSI5)

• Eight calibration segments (for shaping and output response)

The LX3302 and other products in the LX33xx sensor IC family can