Introduction

The NCV77320 is a single−chip inductive position sensor interface

that, in combination with a PCB, forms a system that measures angular

or linear positions accurately.

The operating principle of the inductive sensor is based on mutual

inductance. The chip contains an excitation source, which generates an

AC magnetic field through a primary coil on the PCB. The field

mutually couples to the rotor. The rotor on its turn induces voltages in

secondary coils. These voltages, measured by the chip, depend on the

rotor position and give a measure for the position.

The NCV77320 contains 3 interfaces: A single ended analog output,

a SENT interface with fast and slow channel and a SPI channel for

direct interconnection to a micro controller.

The analog output is proportionally ratio metric with the supply

voltage.

The NCV77320 has several fault detection circuitries. When a fault

is detected, fault flags are set and available for readout. In case the

analog output is used, OUT pin is put to HiZ and its voltage goes to fail

band close to GND or VCC based on the pull−up or pull−down resistor

assembled.

To address automotive functional safety, different kind of topologies

can be implemented, e.g.:

• Two devices with independent supplies. There is no galvanic

connection between the ICs. Each IC drives its own excitation coil

and measures its own set of receiver coils.

• Two devices with their own supply but with a shared excitation coil

connected to both ICs.

Features

• Integrated DSP Position Calculation with Flexible 15 Point

Linearization

• Diagnostics, Including for Missing Wire / Wire Misconnection

Tolerant

• Analog Output or SENT Output Configurable

• Temperature Sensor Embedded

• SPI Watchdog Feature

• Supply Voltage 5 V; −15 V to 30 V Tolerant Robustness

• Flexible SPI Operation with 3.3 V or 5 V Micro Controllers

• Maximum Rotational Speed of 10800 rpm

• Operating Ambient Temperature −40 to 150°C

• Developed According to the Automotive Safety Standard ISO26262

• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS

Compliant