Datasheet

ADS1242, 1243
3
SBAS235H
www.ti.com
ELECTRICAL CHARACTERISTICS: V
DD
= 5V
All specifications T
MIN
to T
MAX
, V
DD
= +5V, f
MOD
= 19.2kHz, PGA = 1, Buffer ON, f
DATA
= 15Hz, V
REF
≡ (REF IN+) – (REF IN–) = +2.5V, unless otherwise specified.
ADS1242
ADS1243
PARAMETER CONDITIONS MIN TYP MAX UNITS
ANALOG INPUT
(A
IN
0 – A
IN
7)
Analog Input Range Buffer OFF GND – 0.1 V
DD
+ 0.1 V
Buffer ON GND + 0.05 V
DD
– 1.5 V
Full-Scale Input Range
(In+) – (In–), See Block Diagram, RANGE = 0 ±V
REF
/PGA V
RANGE = 1
±V
REF
/(2 • PGA) V
Differential Input Impedance Buffer OFF 5/PGA MΩ
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 1 ppm/°C
SYSTEM PERFORMANCE
Resolution No Missing Codes 24 Bits
Integral Nonlinearity End Point Fit ±0.0015 % of FS
Offset Error
(1)
7.5 ppm of FS
Offset Drift
(1)
0.02 ppm of FS/°C
Gain Error
(1)
0.005 %
Gain Error Drift
(1)
0.5 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)
80 95 dB
VOLTAGE REFERENCE INPUT
Reference Input Range REF IN+, REF IN– 0V
DD
V
V
REF
V
REF
≡ (REF IN+) – (REF IN–), RANGE = 0 0.1 2.5 2.6 V
RANGE = 1 0.1 V
DD
V
Common-Mode Rejection at DC 120 dB
Common-Mode Rejection f
VREFCM
= 60Hz, f
DATA
= 15Hz 120 dB
Bias Current
(3)
V
REF
= 2.5V 1.3 µA
POWER-SUPPLY REQUIREMENTS
Power-Supply Voltage V
DD
4.75 5.25 V
Current PGA = 1, Buffer OFF 240 375 µA
PGA = 128, Buffer OFF 450 800 µA
PGA = 1, Buffer ON 290 425 µA
PGA = 128, Buffer ON 960 1400 µA
SLEEP Mode 60 µA
Read Data Continuous Mode 230 µA
PDWN 0.5 nA
Power Dissipation PGA = 1, Buffer OFF 1.2 1.9 mW
TEMPERATURE RANGE
Operating –40 +85 °C
Storage –60 +100 °C
NOTES: (1) Calibration can minimize these errors.
(2) ∆V
OUT
is a change in digital result. (3) 12pF switched capacitor at f
SAMP
clock frequency.