IC-TW8_13 Datasheet, PDF (37/63 Pages) IC-Haus GmbH – 16-BIT SIN/COS INTERPOLATOR WITH AUTO-CALIBRATION

iC-TW8 16-BIT SIN/COS INTERPOLATOR
Serial Configuration Mode
preliminary
Jan 9, 2013 Page SC10/36
Electrical Connections
The basic electrical connections for an encoder us-
ing the iC-TW8 are shown in Figure 8. Other than
the analog sensor, only an EEPROM for parameter
storage and a few bypass capacitors are required for
operation. PINSEL (pin 22) must be connected to
DVSS to select serial configuration mode and either
the SPI or 1-wire serial ports must be connected to
an appropriate master for configuration. A voltage
regulator to supply clean power to the device and a
line driver are recommended. A crystal or oscillator
(clock driver) is recommended for all but the most
cost-sensitive applications.
The iC-TW8 requires a high quality ground and
clean power supplies. Analog ground (AVSS = pin
46) and digital ground (DVSS = pin 15) must both
be connected on the PCB to a solid ground plane.
Analog power (AVDD = pin 38) and digital power
(DVDD = pin 21) inputs must be connected to a low
impedance 5V or 3.3V power source, preferably an
on-board voltage regulator. In addition, AVDD and
DVDD should each have a dedicated 1µF decou-
pling capacitor placed as close to the power pins on
the device as possible.
If the iC-TW8 is used with a line driver (such as the
iC-HD7 or iC-HX) or a high frequency FPGA, it is
especially important to isolate the iC-TW8 power
inputs (AVDD and DVDD) against external noise.
In such applications, a dual voltage regulator such
as the iC-DC is highly recommended. Note that both
AVDD and DVDD must be the same voltage level
(5V or 3.3V).
VDD_TW8
Regulator
VDD_MAIN
10µF
VDD_TW8
VDD_TW8
PINSEL tied to DVSS for
Serial Configuration mode
1µF
MR Sensor
AVDD
AVSS
SIN+
SIN-
COS+
COS-
DVDD
PINSEL
EESEL
DVSS
OUTA
OUTB
OUTZ
1µF
EESEL tied to DVSS.
Line Driver
Calibration Button
1µF
1µF
CALIB
VREF
VC
iC-TW8
SPI_SO
SPI_SI
SPI_SCLK
SPI_xSS
IR
SCL
SDA
WP
}
SPI Communication Port
1-Wire Communication Port
VDD_TW8
SCL
EEPROM
SDA
24AA02
WP
Figure 8: iC-TW8 Electrical Connections (Serial Configuration Mode)
Both pin VC (pin 44) and VREF (pin 45) must be
decoupled to ground with 1µF each as shown. The
EEPROM and the line driver (if used) must be de-
coupled according to their respective requirements.
The calibration button provides an easy means to
activate the auto-calibration feature of the iC-TW8
to set the data path parameters (offset, gain, and
phase) to their optimal values. All pins not explicitly
shown in Figure 8 should be connected to appropri-
ate levels as indicated under Pin Functions in the iC-
TW8 data sheet.
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