IC-TW8_13 Datasheet, PDF (15/63 Pages) IC-Haus GmbH – 16-BIT SIN/COS INTERPOLATOR WITH AUTO-CALIBRATION

iC-TW8 16-BIT SIN/COS INTERPOLATOR
Pin Configuration Mode
preliminary
Jan 9, 2013 Page PC3/15
Electrical Connections
The basic electrical connections for an encoder us-
ing the iC-TW8 are shown in Figure 2. Other than
the analog sensor, only an EEPROM for parameter
storage, eight configuration resistors, and a few by-
pass capacitors are required for operation. PINSEL
(pin 22) must be connected to DVDD to select pin
configuration mode. A voltage regulator to supply
clean power to the device and a line driver are rec-
ommended. An crystal or oscillator (clock driver) is
also recommended.
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
1µF
MR Sensor
AVDD
AVSS
SIN+
SIN–
COS+
COS–
CALIB
Calibration Button
1µF
1µF
VREF
VC
iC-TW8
DVDD
PINSEL
EESEL
DVSS
OUTA
OUTB
OUTZ
VDD_TW8
1µF
C0
C1
C2
C3
SCL
SDA
PINSEL tied to DVDD for
Pin Configuration mode
EESEL tied to DVSS.
Line Driver
8 Configuration
Resistors
VDD_TW8
SCL
EEPROM
SDA
24AA02
Figure 2: iC-TW8 Electrical Connections (Pin 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 2 should be connected to appropri-
ate levels as indicated under Pin Functions in the iC-
TW8 data sheet.
Copyright © 2011–2013 iC-Haus
www.ichaus.com