IC-TW8_13 Datasheet, PDF (19/63 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 PC7/15
Connecting the ABZ Outputs
In pin configuration mode, the iC-TW8 provides
industry-standard quadrature incremental outputs
at OUTA (pin 18) and OUTB (pin 17). If an index
sensor is connected to the ZERO inputs of the iC-
TW8, a Z output synchronous with the AB out-
puts is also available on OUTZ (pin 16). These
outputs can be directly connected to an encoder
counter such as the iC-TW9.
Alternatively, the ABZ outputs can be connected
to a differential line driver (such as the iC-HD7 or
iC-HX) as shown in Figure 10. When using a line
driver it is especially important to isolate the iC-
TW8 from external switching noise using a regu-
lator, as shown.
regulator
3.3V
24V
regulator
5V
line driver
AVDD
DVDD
OUTA
OUTB
OUTZ
AVSS/DVSS
iC-TW8
VCC VB1
VB2
VB3
E1
A1
E3
A2
E5
A3
A4
GNDx A5
A6
iC-HX
Figure 10: Line Driver Connection
Power-Up Sequence
After power-up, the iC-TW8’s POR circuit monitors
the supply voltage and waits until it has reached the
appropriate threshold (as determined by the xRST
connections). The iC-TW8 then starts up using the
internal oscillator (even if a crystal or external clock
source is connected) and executes its start-up cycle as
outlined below.
1. Read parameter values from EEPROM.
2. Set proper clock source and frequency.
3. Read configuration inputs and enable signal
path.
4. Wait for all analog circuitry to settle.
5. Clear all faults.
6. Start ABZ output generation.
If any faults are detected during the start-up cycle, the
iC-TW8 does not enable the AB outputs but goes into
an idle state with the FAULT output (pin 20) asserted
(low).
The amount of time the iC-TW8 waits for the analog
circuitry to settle (twait) depends on the clock fre-
quency as shown by the formula below.
twait[ms] 
1048
fclock[MHz]
For example, using a 32 MHz crystal, the iC-TW8
waits 33 ms for the analog circuitry to settle.
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