ADS1291_14 Datasheet, PDF (3/75 Pages) Texas Instruments – Power, 2-Channel, 24-Bit Analog Front-End for Biopotential Measurements

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ADS1291
ADS1292
ADS1292R
SBAS502B – DECEMBER 2011 – REVISED SEPTEMBER 2012
ELECTRICAL CHARACTERISTICS
Minimum and maximum specifications apply from –40°C to +85°C. Typical specifications are at +25°C. All specifications are
at DVDD = 1.8 V, AVDD – AVSS = 3 V⁽¹⁾, V_REF = 2.42 V, external f_CLK = 512 kHz, data rate = 500 SPS, C_FILTER = 4.7 nF⁽²⁾,
and gain = 6, unless otherwise noted.
ADS1291, ADS1292, ADS1292R
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
ANALOG INPUTS
Full-scale differential input voltage
(AINP – AINN)
±V_REF / gain
V
Input common-mode range
See the Input Common-Mode Range
subsection of the PGA Settings and Input
Range section
Input capacitance
20
pF
Input bias current (PGA chop = 8 kHz)
T_A = +25°C, input = 1.5 V
T_A = –40°C to +85°C, input = 1.5 V
Chop rates other than 8 kHz
±200
pA
±1
nA
See Pace Detect section
No pull-up or pull-down current source
1000
MΩ
DC input impedance
Current source lead-off detection (nA),
AVSS + 0.3 V < AIN < AVDD – 0.3 V
500
MΩ
Current source lead-off detection (µA),
AVSS + 0.6 V < AIN < AVDD – 0.6 V
100
MΩ
PGA PERFORMANCE
Gain settings
1, 2, 3, 4, 6, 8, 12
Bandwidth
With a 4.7-nF capacitor on PGA output
(see PGA Settings and Input Range section
for details)
8.5
kHz
ADC PERFORMANCE
Resolution
24
Bits
Data rate
CHANNEL PERFORMANCE (DC Performance)
Input-referred noise
f_CLK = 512 kHz
Gain = 6⁽³⁾, 10 seconds of data
Gain = 6, 256 points, 0.5 seconds of data
Gain settings other than 6,
data rates other than 500 SPS
125
8000
SPS
8
8
11
See Noise Measurements section
μV_PP
μV_PP
Integral nonlinearity
Full-scale with gain = 6, best fit
2
ppm
Offset error
±100
μV
Offset error drift
2
μV/°C
Offset error with calibration
15
μV
Gain error
Excluding voltage reference error
±0.1
±0.2 % of FS
Gain drift
Excluding voltage reference drift
2
ppm/°C
Gain match between channels
0.2
% of FS
CHANNEL PERFORMANCE (AC performance)
CMRR Common-mode rejection ratio
f_CM = 50 Hz and 60 Hz⁽⁴⁾
–105
–120
dB
PSRR Power-supply rejection ratio
f_PS = 50 Hz and 60 Hz
90
dB
Crosstalk
f_IN = 50 Hz and 60 Hz
–120
dB
SNR
Signal-to-noise ratio
f_IN = 10 Hz input, gain = 6
107
dB
10 Hz, –0.5 dBFs, C_FILTER = 4.7nF
–104
dB
THD
Total harmonic distortion
100 Hz, –0.5 dBFs, C_FILTER = 4.7nF
ADS1292R channel 1, 10 Hz, –0.5 dBFS,
C_FILTER = 47 nF
–95
dB
–82
dB
(1) Performance is applicable for 5-V operation as well. Production testing for limits is performed at 3 V.
(2) C_FILTER is the capacitor accross the PGA outputs; see the PGA Settings and Input Range section for details.
(3) Noise data measured in a 10-second interval. Test not performed in production. Input-referred noise is calculated with input shorted
(without electrode resistance) over a 10-second interval.
(4) CMRR is measured with a common-mode signal of AVSS + 0.3 V to AVDD – 0.3 V. The values indicated are the minimum of the two
channels.
Copyright © 2011–2012, Texas Instruments Incorporated
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