iC-LNG 16-BIT OPTO ENCODER
WITH SPI AND SERIAL / PARALLEL OUTPUTS
Rev A1, Page 19/25
SIGNAL CONDITIONING
iC-LNG has various parameters for signal conditioning. NCOS. The offset of signal NSIN must then be cali-
The gain of the digital tracks and the analog track can brated to the calibrated offset of signal PSIN.
both be set using parameter GR. A gain factor of 1.33
(GR = 0x01) can be used for most applications.
OSP
Code
0x00
0x01
...
Add. 0x02, bit 6:0
Offset value
GR
Add. 0x07, bit 1:0
0.45 · VDDA
Code
0x00
0x01
0x02
0x03
Gain factor
1.0
0.4508 · VDDA
(0.45 + OSP·0.1 ) · VDDA
127
1.33
0x7F
0.55 · VDDA
1.6
2.0
Table 17: PSIN offset
Table 15: Gain range (all tracks)
OSN
Code
0x00
0x01
...
Add. 0x03, bit 6:0
Offset value
The sine/cosine signals can be calibrated in ampli-
tude and offset (Figure 14). To this end the LED
current control must be programmed to sum con-
trol (LCSET(6) = 1) and the internal calibration signals
switched to analog outputs PSIN, NSIN, PCOS, and
NCOS (TA = 0x1).
0.45 · VDDA
0.4508 · VDDA
(0.45 + OSN·0.1 ) · VDDA
127
0x7F
0.55 · VDDA
Table 18: NSIN offset
T
A
=
0
x
1
PS IN
N SI N
To calibrate the cosine signals TMUX must be pro-
grammed to 0x0E. The amplitude of signals PCOS and
NCOS can then be calibrated to the same amplitude as
that of the sine signals using parameter GS.
TM U X = 0 x0D
or
V
P
x
T
M
U
X
=
0
x
0
E
VPx
VN x
V
N
x
PCO S
N C O S
G ND A
V
D
D
A
H
GC
Add. 0x01, bit 5:0
Gain factor
1.0
V
D
D
A
H
Code
0x00
0x01
...
(
x
=
S
,
C
)
1.01
1+GC·0.0053
1−GC·0.0053
Figure 14: Sine/cosine signal calibration
0x3F
2.0
To calibrate the sine signals TMUX must be pro-
grammed to 0x0D. The amplitude of signals PSIN and
NSIN can then be calibrated using parameter GS. The
target amplitude is 500 mVp.
Table 19: PCOS and NCOS gain
The offsets of PCOS and NCOS can be calibrated sep-
arately using parameters OCP and OCN. The offset
of signal PCOS must be calibrated to reference signal
VDDAH. This signal is available in test mode at pin
NCOS. The offset of signal NCOS must then be cali-
brated to the calibrated offset of signal PCOS.
GS
Add. 0x00, bit 5:0
Gain factor
1.0
Code
0x00
0x01
...
1.01
1+GS·0.0053
1−GS·0.0053
0x3F
2.0
OCP
Code
0x00
0x01
...
Add. 0x04, bit 6:0
Offset value
Table 16: PSIN and NSIN gain
0.45 · VDDA
0.4508 · VDDA
(0.45 + OCP·0.1 ) · VDDA
127
The offsets of PSIN and NSIN can be calibrated sep-
arately using parameters OSP and OSN. The offset
of signal PSIN must be calibrated to reference signal
VDDAH. This signal is available in test mode at pin
0x7F
0.55 · VDDA
Table 20: PCOS offset
ICHAUS [ IC-HAUS GMBH ]
