Datasheet

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SBAS306F − NOVEMBER 2004 − REVISED OCTOBER 2007
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3
ELECTRICAL CHARACTERISTICS
All specifications at T
A
= −40°C to +105°C, AVDD = +5V, DVDD = +1.8V, f
CLK
= 27MHz, VREFP = 2.5V, and VREFN = 0V, unless otherwise noted.
Specified values for ADS1271 and ADS1271B (high-grade version) are the same, except where shown in BOLDFACE type.
ADS1271 ADS1271B
PARAMETER TEST CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
Analog Inputs
Full-scale input voltage (FSR
(1)
) V
IN
= (AINP – AINN) ±V
REF
±V
REF
V
Absolute input voltage AINP or AINN to AGND AGND – 0.1 AVDD + 0.1 AGND – 0.1 AVDD + 0.1 V
Common-mode input voltage V
CM
= (AINP + AINN)/2 2.5 2.5 V
Differential
High-Speed mode 16.4 16.4 kΩ
Differential
input
impedance
High-Resolution mode 16.4 16.4 kΩ
input
impedance
Low-Power mode 32.8 32.8 kΩ
DC Performance
Resolution No missing codes 24 24 Bits
Data rate
High-Speed mode 105,469 105,469 SPS
Data rate
(f
DATA
)
High-Resolution mode 52,734 52,734 SPS
(f
DATA
)
Low-Power mode 52,734 52,734 SPS
Integral nonlinearity (INL)
Differential input,
V
CM
= 2.5V
± 0.0006 ± 0.0015 ± 0.0006 ± 0.0015 %FSR
(1)
Offset error
High-Speed mode Without calibration 0.150 1 0.150 1 mV
Offset error
With calibration On the level of the noise
Offset drift 1.8 1.8 µV/_C
Gain error 0.1 0.5 0.1 0.5 %FSR
(1)
Gain error drift 2 2 ppm/°C
High-Speed mode Shorted input 9.0 20 9.0 16 µV, rms
Noise
High-Resolution mode 6.5 6.5 12 µV, rms
Noise
Low-Power mode 9.0 9.0 16 µV, rms
Common-mode rejection f
CM
= 60Hz 90 100 95 110 dB
Power-supply
AVDD
f = 60Hz
80 80 dB
Power-supply
rejection
DVDD
f = 60Hz
80 80 dB
AC Performance
Signal-to-noise
(2)
High-Speed mode 99 106 101 106 dB
Signal-to-noise
ratio (SNR)
(2
)
(unweighted)
High-Resolution mode 109 103 109 dB
ratio (SNR)
(unweighted)
Low-Power mode 106 101 106 dB
Total harmonic distortion (THD)
(3)
V
IN
= 1kHz, −0.5dBFS −105 −95 −108 −100 dB
Spurious-free dynamic range −108 −109 dB
Passband ripple ±0.005 ±0.005 dB
Passband 0.453 f
DATA
0.453 f
DATA
Hz
−3dB Bandwidth 0.49 f
DATA
0.49 f
DATA
Hz
Stop band attenuation 100 100 dB
High-Speed mode 0.547 f
DATA
63.453 f
DATA
0.547 f
DATA
63.453 f
DATA
Hz
Stop band
High-Resolution mode 0.547 f
DATA
127.453 f
DATA
0.547 f
DATA
127.453 f
DATA
Hz
Stop band
Low-Power mode 0.547 f
DATA
63.453 f
DATA
0.547 f
DATA
63.453 f
DATA
Hz
Group delay
High-Speed and
Low-Power modes
38/f
DATA
38/f
DATA
s
Group delay
High-Resolution mode 39/f
DATA
39/f
DATA
s
Settling time
(latency)
High-Speed and
Low-Power modes
Complete settling 76/f
DATA
76/f
DATA
s
(latency)
High-Resolution mode Complete settling 78/f
DATA
78/f
DATA
s
(1)
FSR = full-scale range = 2V
REF
.
(2)
Minimum SNR is ensured by the limit of the DC noise specification.
(3)
THD includes the first nine harmonics of the input signal.
(4)
MODE and FORMAT pins excluded.
(5)
See the text for more details on SCLK.