MAX11209 View Datasheet(PDF) - Maxim Integrated
Part Name
Description
Manufacturer
MAX11209
Maxim Integrated
MAX11209 Datasheet PDF : 27 Pages
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MAX11209/MAX11211
18-Bit, Single-Channel, Ultra-Low-Power, Delta-
Sigma ADCs with Programmable Gain and GPIO
Table 3a. Example of Self-Calibration
REGISTER
BIT
STEP
DESCRIPTION
SCOC
SCGC
SOC
SGC
1 Initial power-up
2 Enable self-calibration registers
3 Self-calibration, DIN = 10010000
0x000000 0x000000 0x000000 0x000000 1
1
1
1
0x000000 0x000000 0x000000 0x000000 1
1
0
0
0x00007E 0xBFD345 0x000000 0x000000 1
1
0
0
Table 3b. Example of System Calibration
REGISTER
BIT
STEP
DESCRIPTION
SCOC
SCGC
SOC
SGC
1 Initial power-up
0x000000 0x000000 0x000000 0x000000 1
1
1
1
2 Enable self-calibration registers
0x000000 0x000000 0x000000 0x000000 1
1
0
0
3 Self-calibration, DIN = 10010000
0x00007E 0xBFD345 0x000000 0x000000 1
1
0
0
4 Enable system offset register
0x00007E 0xBFD345 0x000000 0x000000 1
0
0
0
5 System-calibration offset, DIN = 1010000 0x00007E 0xBFD345 0xFFEE1D 0x000000 1
0
0
0
6 Enable system gain register
0x00007E 0xBFD345 0xFFEE1D 0x000000 0
0
0
0
7 System-calibration gain, DIN = 1011000 0x00007E 0xBFD345 0xFFEE1D 0x81CB5B 0
0
0
0
Noise vs. Data Rate
The devices offer software-selectable internal oscillator
frequencies as well as software-selectable output data
rates. The LINEF bit in the CTRL1 register (Table 12)
determines the internal oscillator frequency. The RATE
bits in the command byte (Table 8) determine the ADC’s
output data rate. The devices also offer the option of
running in zero latency single-cycle conversion mode
(Table 2) or continuous conversion mode (Table 1). Set
SCYCLE = 0 in the CTRL1 register (Table 12) to run in
continuous conversion mode and SCYCLE = 1 for single-
cycle conversion mode.
Single-cycle conversion mode gives an output result with
no data latency. The devices output data up to 100sps
(2.048MHz internal oscillator) or 120sps (2.4576MHz
internal oscillator) with no data latency. In continuous
conversion mode, the output data rate is four times the
single-cycle conversion mode, for sample rates up to
400sps or 480sps. In continuous conversion mode, the
output data requires three additional 24-bit cycles to
settle from an input step.
Digital Filter
The devices include a SINC4 digital filter that produces
spectral nulls at the multiples of the data rate. For all
data rates less than 30sps, a spectral null occurs at the
line frequency of 60Hz and is guaranteed to attenuate
60Hz normal-mode components by more than 100dB.
Simultaneous 50Hz and 60Hz attenuation can be accom-
plished by using an external clock with a frequency of
2.25275MHz. This guarantees a minimum of 80dB rejec-
tion at 50Hz and 85dB rejection at 60Hz. The SINC4 filter
has a -3dB frequency equal to 24% of the data rate. See
Figures 1 and 2.
GPIOs
The devices provide four GPIO ports. When set as out-
puts, these digital I/Os can be used to drive the digital
inputs to a multiplexer or multichannel switch. Figure 3
details an example where four single-ended signals are
multiplexed in a break-before-make switching sequence,
using the MAX313, a quad SPST analog switch.
The devices’ GPIO ports are configurable through the
CTRL2 register. See Table 13. To select AIN1, write the
command to CTRL2 according to Table 4a. This selects
all GPIOs as outputs, as well as setting all logic signals
to 0 except the selected channel AIN1.
To select channel AIN3 next, it is a good idea to set all
switches to a high-impedance state first (see Table 4b).
Then select channel AIN3 by driving IN3 high (see
Table 4c).
Maxim Integrated
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