Datasheet

ADS1240, 1241
4
SBAS173F
www.ti.com
ELECTRICAL CHARACTERISTICS: AV
DD
= 3V
All specifications –40°C to +85°C, AV
DD
= +3V, DV
DD
= +2.7V to 5.25V, f
MOD
= 19.2kHz, PGA = 1, Buffer ON, f
DATA
= 15Hz, and V
REF
= +1.25V, unless otherwise specified.
ADS1240
ADS1241
PARAMETER CONDITIONS MIN TYP MAX UNITS
ANALOG INPUT
(A
IN
0 – A
IN
7, A
INCOM
)
Analog Input Range Buffer OFF AGND – 0.1 AV
DD
+ 0.1 V
Buffer ON AGND + 0.05 AV
DD
– 1.5 V
Full-Scale Input Voltage Range
(In+) – (In–) See Block Diagram, RANGE = 0 ±V
REF
/PGA V
RANGE = 1
±V
REF
/(2 • PGA) V
Input Impedance Buffer OFF 5/PGA MΩ
Differential Buffer ON 5 GΩ
Bandwidth
f
DATA
= 3.75Hz –3dB 1.65 Hz
f
DATA
= 7.50Hz –3dB 3.44 Hz
f
DATA
= 15.00Hz –3dB 14.6 Hz
Programmable Gain Amplifier User-Selectable Gain Ranges 1 128
Input Capacitance 9pF
Input Leakage Current Modulator OFF, T = 25°C5 pA
Burnout Current Sources 2 µA
OFFSET DAC
Offset DAC Range RANGE = 0 ±V
REF
/(2 • PGA) V
RANGE = 1 ±V
REF
/(4 • PGA) V
Offset DAC Monotonicity 8 Bits
Offset DAC Gain Error ±10 %
Offset DAC Gain Error Drift 2 ppm/°C
SYSTEM PERFORMANCE
Resolution No Missing Codes 24 Bits
Integral Nonlinearity End Point Fit ±0.0015 % of FS
Offset Error
(1)
15 ppm of FS
Offset Drift
(1)
0.04 ppm of FS/°C
Gain Error 0.01 %
Gain Error Drift
(1)
1.0 ppm/°C
Common-Mode Rejection at DC 100 dB
f
CM
= 60Hz, f
DATA
= 15Hz 130 dB
f
CM
= 50Hz, f
DATA
= 15Hz 120 dB
Normal-Mode Rejection f
SIG
= 50Hz, f
DATA
= 15Hz 100 dB
f
SIG
= 60Hz, f
DATA
= 15Hz 100 dB
Output Noise See Typical Characteristics
Power-Supply Rejection at DC, dB = –20 log(∆V
OUT
/∆V
DD
)
(2)
75 90 dB
VOLTAGE REFERENCE INPUT
V
REF
V
REF
≡ (REF IN+) – (REF IN–), RANGE = 0 0.1 1.25 1.30 V
Reference Input Range REF IN+, REF IN– 0 AV
DD
V
RANGE = 1 0.1 2.5 2.6 V
Common-Mode Rejection at DC 120 dB
Common-Mode Rejection f
VREFCM
= 60Hz, f
DATA
= 15Hz 120 dB
Bias Current
(3)
V
REF
= 1.25 0.65 µA
POWER-SUPPLY REQUIREMENTS
Power-Supply Voltage AV
DD
2.7 3.3 V
Analog Current PDWN = 0, or SLEEP 1 nA
PGA = 1, Buffer OFF 107 225 µA
PGA = 128, Buffer OFF 355 600 µA
PGA = 1, Buffer ON 118 275 µA
PGA = 128, Buffer ON 483 1225 µA
Digital Current Normal Mode, DV
DD
= 3V 50 100 µA
SLEEP Mode, DV
DD
= 3V 40 µA
Read Data Continuous Mode, DV
DD
= 3V 113 µA
PDWN = 0 0.5 nA
Power Dissipation PGA = 1, Buffer OFF, DV
DD
= 3V 0.6 1.2 mW
NOTES: (1) Calibration can minimize these errors to the level of the noise.
(2) ∆V
OUT
is a change in digital result.
(3) 12pF switched capacitor at f
SAMP
clock frequency.