MAX11043 Datasheet, PDF (14/33 Pages) Maxim Integrated Products – 4-Channel, 16-Bit, Simultaneous-Sampling ADCs with PGA, Filter, and 8-/12-Bit Dual-Stage DAC

4-Channel, 16-Bit, Simultaneous-Sampling ADCs
with PGA, Filter, and 8-/12-Bit Dual-Stage DAC
Filter coefficients A1 and B1 are always 1. B3 is limited
to -1, 0, and 1.
Filter coefficients A2, A3, and B2 are stored as 16-bit
two’s complement values in the range of -4 to +4. Filter
coefficients A2 and A3 are stored as -A2 and -A3.
Gain is limited to the following values 2⁴, 2², 2⁰, 2^-2, 2^-4,
2^-6, 2^-8, and 2^-10. For better gain resolution, adjust the
Fine Gain A/B/C/D Registers at the input of each filter
set. Fine gain adjustment has a resolution of 16 bits and
a gain range of -4 to +4. Set the RECT bit to rectify the
filter output.
Figures 5–8 show the response to a step input of the
default filters used for ADC trimming.
IN ⁺
1/A1
RECT
B1
G
+
ABS
OUT
SINC 5 FILTER OUTPUT
2500
2000
Z^-1
1500
X
+
-A2
B2
+
1000
Z^-1
Y
-A3
B3
Figure 4. Single Programmable 2nd-Order Filter Section
500
0
0
2
4
6
8
10
SAMPLE
Figure 5. Sinc 5 Filter Response to a Step Input
Table 1. Default Filter Coefficients
STAGE
1
2
3
4
5
6
7
STAGE
1
2
3
4
5
6
7
DEFAULT LOWPASS FILTER COEFFICIENTS
B1
B2
B3
A1
A2
1
+ 2.0 (typ)
+1.0000
1
+0.468 (typ)
1
+1.9509
+1.0000
1
+0.6874
1
+1.6139
+1.0000
1
+0.5936
1
+1.1488
+1.0000
1
+0.4395
1
+0.7415
+1.0000
1
+0.2715
1
+0.4651
+1.0000
1
+0.1310
1
+0.3296
+1.0000
1
+0.0493
DEFAULT EQUALIZER COEFFICIENTS
B1
B2
B3
A1
A2
1
+ 2.0 (typ)
+1.0000
1
+0.468 (typ)
1
+1.9401
+1.0000
1
+0.6886
1
+1.5458
+1.0000
1
+0.5803
1
+1.0518
+1.0000
1
+0.4139
1
+0.6785
+1.0000
1
+0.2563
1
-1.0000
+0.0000
1
+0.0039
1
+0.4902
+1.0000
1
+0.1649
A3
+0.607 (typ)
+0.1317
+0.2015
+0.3258
+0.4851
+0.6685
+0.8788
A3
+0.607 (typ)
+0.1359
+0.2275
+0.3887
+0.5966
-0.0000
+0.8489
14 ______________________________________________________________________________________
GAIN
+0
-2
-2
+0
+0
+0
+0
GAIN
+0
+0
-2
+0
+0
+4
+2