iC-MQ PROGRAMMABLE 9-BIT
Sin/Cos INTERPOLATION IC WITH RS422 DRIVER
Rev D4, Page 21/39
SIGNAL CONDITIONING CH1, CH2
GR12
Code
0x0
Adr 0x04, bit 2:0
The analog voltage signals necessary for the calibra-
tion of the sine signals can be measured in operation
mode Calibration 2. Alternatively, characteristic digital
test signals are also available for offset, amplitude and
phase errors in operating mode System Test.
Range RIN12=0x9
Range RIN12=0x9
0.5
1.0
1.3
1.7
2.2
2.6
3.3
4.0
2.0
0x1
4.1
0x2
5.3
0x3
6.7
0x4
8.7
Gain Settings
The gain is set in four steps:
0x5
10.5
13.2
16.0
0x6
0x7
1. The sensor supply controller is shut down and the
constant current source for the ACO output set to a
suitable output current (register ADJ; current value
close to the later operating point).
Table 23: Gain Range CH1, CH2
GF2
Code
0x00
0x01
...
Adr 0x04, bit 7:3
Factor
2. The coarse gain is selected so that differential signal
amplitudes of ca. 1 Vpp are produced internally (signal
Px versus Nx, see Figure).
1.00
1.06
6.25GF2
31
3. Using fine gain factor GF2 the CH2 signal amplitude
is then adjusted to 1 Vpp.
0x1F
6.25
Table 24: Fine Gain Factor CH2
4. The CH1 signal amplitude can then be adjusted to
the CH2 signal amplitude via fine gain factor GF1. This
results in a total gain of GR12 * GFi for differential input
signals.
GF1
Code
0x00
0x01
...
Adr 0x06, bit 2:0, Adr 0x05, bit 7:4
Factor
1.0
1.015
GF1
124
6.25
0x7F
6.53
Table 25: Fine Gain Factor CH1
Px
VPNx
R0
VPx
Nx
VNx
GND
Figure 4: Definition of 1 Vpp signal. Termination R0
must be high-ohmic during all Test and
Calibration modes.
ICHAUS [ IC-HAUS GMBH ]
