iC-TW8 16-BIT SIN/COS INTERPOLATOR WITH AUTO-CALIBRATION iC-TW8 is a general-purpose, 16-bit interpolation device for sine/cosine signals featuring automatic signal conditioning. The angular position is calculated at a constant latency of just 24 μs and can be tracked by an optional second-order servo loop that provides lag retrieval. The automatic signal conditioning unit includes offset compensation, amplitude correction, and phase correction. Additionally, an LUT can be used to correct the digitized phase angle depending on the sensor’s harmonic signal distortion. Applications • • • • Sine/cosine interpolation Signal conditioning with auto calibration Linear and rotary encoders Flexible incremental encoder systems Features • • • • • • • • • • • • • Input frequency of up to 125 kHz Differential sine/cosine input signal range of 20 mV to 1.4 V peak-peak Fractional interpolation factor edged per period of [8 ... 65536] / [1 ... 32] Simple automatic one-pin calibration Easy configuration: by static pins (for generic ABZ output) Advanced configuration: 1-wire interface, 3 and 4-wire SPI (32 MHz), EEPROM (SPI or I²C) PWM or ABZ quadrature encoder output signals Incremental ABZ output to 8 MHz (32 MHz edge separation) Position and velocity read-out (32 bit SPI) Sophisticated error handling and signal monitoring Static 64 position LUT to compensate for arbitrary sensor distortions Supply voltage range of 3.1 V to 5.5 V Extended temperature range of -40 °C to +125 °C 48-pin QFN package 7 mm x 7 mm Am Kuemmerling 18 • D -55294 Bodenheim, Germany Tel. +49 61 35 / 92 92-30 0 • Fax +49 61 35 / 92 92-19 2 • http://www.ichaus.com iC-TW8 16-BIT SIN/COS INTERPOLATOR WITH AUTO-CALIBRATION Novel push-button calibration Key Specifications iC-TW8 offers two principle means of setup: easy static pin configuration and the SPI/1-wire interface. Static pin configuration is provided with simple automatic calibration and ABZ quadrature output mode. It uses four configuration inputs and is preselected by input PINSEL. The self-learning automatic function requires input signals of a few seconds only and tolerates changes in frequency and cw/ ccw direction. For more advanced setup requirements the SPI interface or the 1-wire interface can be used to take full control of the device. Pin Functions QFN48 7x7 mm2 Inputs and Analog Signal Conditioning Max. Input Frequency 125 kHz Diff. Input Signal Range 20 mVpp to 1.4 Vpp (differential) Sin/Cos Input Signal Range 1.4 V to AVDD – 1 V Analog Gain Range 6 to 45 dB, step 3 dB (auto. tracking) Analog Offset Compensation +/- 3.1 V, step 100 mV (auto. tracking) Zero Inputs Signal Range 0 V to AVDD Digital Sin/Cos Signal Conditioning Offset Correction +/- 125 mV, step 244 µV (auto. tracking) Offset Correction Range +/- 9 % of amplitude Differential Gain Correction x0.8 to x1.25, step x0.002 (auto. track.) Amplit. Mismatch Corr. Range +/- 25 % of amplitude Digital Phase Correction +/- 26°, step 0.025° (auto. tracking) Function Pin I/O Description xRST 2 in Reset Input FAB 3 in Test Enable Input EESEL 4 in External EEPROM Selection Input CALIB 5 in Calibration Control CLOCK/GP1 6 in/out Clock Output / General Purpose I/O IR 7 in/out 1-Wire Interface I/O FRAME/GP0 8 in/out Sync Output / General Purpose I/O SPI_SO 9 out SPI Slave Output SPI_SI 10 in SPI Slave Input SPI_SCLK 11 in SPI Slave Clock Input SPI_xSS 14 in SPI Slave Select Input DVSS 15 ground Digital Ground OUTZ 16 out Z Output OUTB 17 out B Output / PWM- Outp. / Z Window OUTA 18 out A Output / PWM+ Outp. / Z Window STATUS 19 out PWM Status Output ERR 20 out Error Status Output DVDD 21 power +3.1 V to +5.5 V Dig. Power Supply PINSEL 22 in Configuration Mode Selection Absolute Position Data MI 26 in SPI EEPROM Master Input SCL/SCLK 27 in/out I2C / SPI Clock Line Angle Position 32 bit (with 16 bit for counted periods) SDA/MO 28 in/out I2C / SPI Data Line Angle Velocity 14 bit (up to ±45 M°/s, 5.4 k°/s resol.) WP/xCS 29 out I2C Write Prot. / SPI Slave Selection Interface and Configuration Cx/GPx 30...33 a/d Static Config. Input / GPIO Configuration Storage XOUT 34 a Crystal Terminal SPI standard SPI, SCLK up to 32 MHz XIN 35 a Crystal Terminal 1-Wire AVDD 38 power +3.1 V to +5.5 V Analog Pwr. Supply PWM interface for in-field wireless configuration (e.g. using IR) SIN+ 39 a Sine Input + Static 4-Pin Configuration by 8 resistors, no programming SIN- 40 a Sine Input - Offset/Gain/Phase Calibration COS+ 41 a Cosine Input + push-button automatic with storage of parameters in external EEPROM COS- 42 a Cosine Input - AVSS 43 ground Analog Ground VC 44 a Bias Output VREF 45 a Bias Output AVSS 45 ground Analog Ground ZERO+ 46 a Zero Input + ZERO- 47 a Zero Input - NB: a: analog; a/d: analog/digital Sine-to-Digital Conversion Sampling Rate max 250 kHz at 5 V (187 kHz at 3.3 V) ATAN Calculation 14 bit raw, 16 bit filtered Integral Nonlinearity 0.08° Differential Nonlinearity 0.02° Distortion Compensation 64 arbitrary positions by look-up-table Dist. Compensation Range +/- 11° Incremental Outputs Fractional Interpolation Factor [8 ... 65536] / [1 ... 32] Output Signals A/B quadrature, programmable index Z Output Characteristics TTL/CMOS compatible, +/- 4 mA Max. Output Frequency programmable 62 kHz to 8 MHz Min. Transition Distance progr. 4 µs to 31.25 ns @ fclk 32 MHz Input-To-Output Latency 24 µs Input-To-Output Lag 4 µs with position lag retrieval Other Features servo loop for superb AB jitter external I2C 24xx02 EEPROM Other Operational Data Supply Voltage 3.1 V to 5.5 V, approx. 15 mA (@ 3.3 V) Operational Temperature -40 °C to +125 °C System Clock On-chip RC 16 MHz to 32 MHz, crystal to 32 MHz (24 MHz @ 3.3 V) Monitoring Functions missing EEEPROM, checksum, compromised input signals, excessive AB frequency, runaway of compensation This preliminary information is not tantamount to a guarantee of device characteristics. All rights to technical changes reserved Am Kuemmerling 18 • D -55294 Bodenheim, Germany Tel. +49 61 35 / 92 92-30 0 • Fax +49 61 35 / 92 92-19 2 • http://www.ichaus.com Rev. 1.0