iC-NQC
13-bit Sin/D CONVERTER WITH SIGNAL CALIBRATION
Rev B1, Page 13/29
MAXIMUM POSSIBLE CONVERTER FREQUENCY
The converter frequency automatically adjusts to the LSB is kept stable and not resolved any further; the
value required by the input frequency and resolution. interpolation resolution halves.
This value ranges from zero to a maximum depen-
dent on the oscillator frequency that is set via register If the next frequency limit is overshot, the LSB and LSB
FCTR.
+1 are kept stable and so on. If the input frequency
again sinks below this frequency threshold, fine reso-
lution automatically returns.
Serial data output
For BiSS or SSI output the maximum possible con-
verter frequency can be adjusted to suit the maxi- With the programming of CRC6 = 1 a resolution step-
mum input frequency; an automatic converter resolu- down will be signalled via the BiSS warning bit.
tion step-down feature can be enabled via the FCTR
register. Should the input frequency exceed the fre-
quency limit of the selected converter resolution, the
Max. Possible Converter Frequency For Serial Data Output
Resolution
Protocol
Max. Input Frequency
Restrictions
Examples*
Requirements
at high input frequency
finmax [kHz] at resol.
8192 1024 200
FCTR
Min. Res. bin dec BiSS SSI finmax
0x0004
0x4102
0x4202
0x4302
0x4702
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
f(OSC)min / 40 / Resolution
–
0.16
0.26
0.53
1.06
1.27
2.1
4.2
8.5
16.9
33.8
67.7
135
250
-
6.5
≥ 8
f(OSC)min / 24 / Resolution Rel. angle error 2x increased
10.8
≥ 16
≥ 32
≥ 64
2 x f(OSC)min / 24 / Res.
4 x f(OSC)min / 24 / Res.
8 x f(OSC)min / 24 / Res.
16 x f(OSC)min / 24 / Res.
32 x f(OSC)min / 24 / Res.
64 x f(OSC)min / 24 / Res.
Rel. angle error 4x increased
Rel. angle error 8x increased
21.6
43.3
Resolution lowered by factor of 2 2.1
-
-
-
-
-
-
-
-
0x4B02 ≥ 128
0x4F02 ≥ 256
-
Res. lowered by factor of 2-4
Res. lowered by factor of 2-8
Res. lowered by factor of 2-16
4.2
-
8.5
0x5302
0x5702
≥ 512
-
16.9
33.8
67.7
135
250
≥ 1024
-
128 x f(OSC)min / 24 / Res. Res. lowered by factor of 2-32
256 x f(OSC)min / 24 / Res. Res. lowered by factor of 2-64
512 x f(OSC)min / 24 / Res. Res. lowered by factor of 2-128
1024 x f(OSC)min / 24 / Res. Res. lowered by factor of 2-256
0x5B02 ≥ 2048
0x5F02 ≥ 4096
-
-
-
0x6302
Notes
8192
-
-
*) Calculated with fosc()min taken from Electrical Characteristics, item A01.
Table 15: Maximum converter frequency for serial data output.
ICHAUS [ IC-HAUS GMBH ]
