MCP37211-200 Datasheet, PDF (52/142 Pages) Microchip Technology – Power-Saving Modes

MCP37211-200 AND MCP37D11-200
Tables 4-13 and 4-14 show the NSR filter selections.
The selectable filters (tuning word) for each mode are:
• 11-bit mode: 0 to 41
• 12-bit mode: 42 to 76
NSR does not affect harmonic distortion. Various FFT
spectrum plots when NSR is applied are shown in
Figures 3-14 to 3-15, Figures 3-17 to 3-20 and
Figures 3-22 to 3-23. SNR and SFDR performance
versus input amplitude when NSR is enabled is shown
in Figures 3-26 and 3-29.
In this case, SNR and SFDR are measured within the
12-bit mode NSR bandwidth (25% of the sampling
frequency). When the NSR block is disabled, the ADC
data is provided directly to the output.
TABLE 4-12: REGISTER CONTROL PARAMETERS FOR NSR
Control Parameter
Register
Descriptions
NSR Enable bits
<EN_NSRA_11>
0x7A Enable 11-bit NSR for channel A
<EN_NSRA_12>
0x7A Enable 12-bit NSR for channel A
<EN_NSRB_11>
0x7A Enable 11-bit NSR for channel B
<EN_NSRB_12>
0x7A Enable 12-bit NSR for channel B
NSR Settings
NSRA<6:0>
0x78 NSR A settings for single-channel or channel A for dual-channel mode
NSRB<6:0>
0x79 NSR B settings for channel B in dual-channel mode
NSR Block Reset Control
<EN_NSR_RESET>
0x78 Resets NSR in the event of overload
Digital Post Processing (DPP) Function Block Settings
EN_DPPDUAL
0x79 Enable DPP block for dual-channel mode
TABLE 4-13: 11-BIT NSR FILTER
SELECTION⁽¹⁾
NSR Filter No.
(Tuning Word)
f_Center/f_S
f_B
(% of f_S)
NSRA<6:0>
NSRB<6:0>
0
0.12
22
000-0000
1
0.133
22
000-0001
2
0.146
22
000-0010
—
—
19
0.367
22
001-0011
20
0.38
22
001-0100
21
0.125
25
001-0101
22
0.1375
25
001-0110
23
0.15
25
001-0111
—
—
40
0.3625
25
010-1000
41
0.375
25
010-1001
Note 1: Filters 0 - 41 are used for 11-bit mode
only. If these are used for 12-bit mode, the
output becomes unknown state.
TABLE 4-14: 12-BIT NSR FILTER
SELECTION⁽¹⁾
NSR Filter No.
(Tuning Word)
f_Center/f_S
f_B
(% of f_S)
NSRA<6:0>
NSRB<6:0>
42
0.125
25
010-1010
43
0.1375
25
010-1011
44
0.15
25
010-1100
—
61
0.3625
25
011-1101
62
0.375
25
011-1110
63
0.15
29
011-1111
64
0.1667
29
100-0000
65
0.1833
29
100-0001
—
—
75
0.35
29
100-1011
76
0.3667
29
100-1100
Note 1: Filters 42 - 76 are used for 12-bit mode
only. If these are used for 11-bit mode, the
output becomes unknown state.
DS20005355C-page 52
 2014-2016 Microchip Technology Inc.