iC-NQI TSSOP20

Description

iC-NQI is a monolithic A/D converter which, by applying a count-safe vector follower principle, converts sine/cosine sensor signals with a selectable resolution and hysteresis into angle position data. The front-end amplifiers are configured as instrumentation amplifiers, permitting sensor bridges to be directly connected without the need for external resistors. Various programmable D/A converters are available for the conditioning of sine/cosine sensor signals with regard to offset, amplitude ratio and phase errors. Front-end gain can be set in stages graded to suit all common differential sensor signals from approximately 20 mVpp to 1.5 Vpp, and also single-end sensor signals from 40 mVpp to 3 Vpp respectively. Two serial interfaces have been included to permit configuration of the device: I2C for the connection of an EEPROM and a 2-wire interface for configuration from a microcontroller. A low signal at pin NPRG is required to release the 2-wire interface for programming, whereas a high signal at pin NPRG preselects the serial output of measurement data. For measurement data output, the fast synchronousserial 2-wire interface can follow an SSI protocol at clock rates of up to 4 Mbit/s, or a BiSS unidirectional protocol featuring error messages and a CRC-protected transmission at clock rates of up to 10 Mbit/s. A configurable period counter can supplement the measurement data by a multiturn count of up to 24 bits. At the same time any changes in output data are converted into incremental A QUAD B encoder signals. Here, the minimum transition distance can be adapted to suit the system on hand (limitations due to counter input frequency, cable length, EMI). A synchronized index signal is generated and output to Z if enabled by the PZERO and NZERO inputs. If the EEPROM is detected following a power-down reset, the CRC-protected chip setup is read in automatically.

Features