IC-TW8_13 Datasheet, PDF (21/63 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 PC9/15
Setting the Interpolation Factor
Configuration inputs C0 and C1 are used to select
the interpolation factor. Input C1 selects the desired
interpolation group I0, I1, or I2 and input C0 selects
the desired interpolation factor from within the se-
lected group. Choose the desired interpolation factor
from Table 2 and connect the appropriate resistors
to configuration input C0 (pin 30) according to Ta-
ble 1 to set the corresponding configuration level.
Setting the Auto-Adaption Mode
Configuration input C1 is used to select the desired
auto-adaption mode and the interpolation group cor-
responding to the interpolation factor selected via
configuration input C0. Choose the desired auto-
adaption mode and interpolation group from Table 3
and connect the appropriate resistors to configura-
tion input C1 (pin 31) according to Table 1 to set the
corresponding configuration level.
C0
Level
11
10
9
8
7
6
5
4
3
2
1
0
Interp.
Group I0
x8192¹
x4096²
x2048
x1024
x512
x256
x128
x64
x32
x16
x8
x4
Interp.
Group I1
x1600
x800
x400
x200
x160
x100
x80
x50
x40
x20
x10
x5
Interp.
Group I2
x10000¹
x5000²
x2500
x1250
x1000
x500
x250
x125
x62.5³
x25
x12.5³
x6.25³
Table 2: Configuration Input C0
The interpolation factors shown in Table 2 are the
number or AB output cycles per Sin/Cos input cy-
cle. There are four times as many AB output edges
per Sin/Cos input cycle than as shown in the table.
Note that while the iC-TW8 is a true 16-bit interpo-
lator, x10000 is the maximum interpolation factor
available in pin configuration mode. Full 16-bit
(x16384) interpolation is available in serial configu-
ration mode.
1 This interpolation factor can only be used with heavy
filtering (C2 configuration levels 8–11) and lag
recovery enabled (C3 configuration levels 6–11).
2 This interpolation factor can only be used with normal
or heavy filtering (C2 configuration levels 4–11) and
lag recovery enabled (C3 configuration levels 6–11).
3 _{Z output is not synchronous with AB outputs when}
using fractional interpolation factors.
C1
Level
11
10
9
8
7
6
5
4
3
2
1
0
Auto-Adaption
Mode
A3: Full analog
and digital auto-
adaption.
A2: Full digital
auto-adaption.
A1: Digital offset
and gain auto-
adaption.
A0: No auto-
adaption.
Interpolation
Group
I2
I1
I0
I2
I1
I0
I2
I1
I0
I2
I1
I0
Table 3: Configuration Input C1
Three auto-adaption modes are available in pin con-
figuration mode. Mode A3 provides full analog and
digital auto-adaption. In this mode, the iC-TW8
continuously adjusts analog gain, analog offset,
digital offset, digital gain, and digital phase during
operation to maintain optimum performance and
lowest error and jitter.
Auto-adaption mode A2 provides full digital auto-
adaption and is the recommended mode for most
applications. In this mode, analog gain and offset
are fixed at the values established during device cal-
ibration (see Auto Calibration on page 12) and the
iC-TW8 continuously adjusts only the digital offset,
digital gain match, and digital phase during opera-
tion to maintain optimum performance and lowest
error and jitter.
Auto-adaption mode A1 is similar to mode A2 ex-
cept that digital phase is fixed at the value estab-
lished during device calibration and not adjusted
during operation.
In mode A0, auto-adaption is disabled and parame-
ter values are not adjusted from their initial calibra-
tion values during operation.
Copyright © 2011–2013 iC Haus
www.ichaus.com