Datasheet

ADS1244
3
SBAS273
www.ti.com
ELECTRICAL CHARACTERISTICS
All specifications –40°C to +85°C, AVDD = 5V, DVDD = +3V, f
CLK
= 2.4576MHz, and V
REF
= 2.5V, unless otherwise specified.
ADS1244
PARAMETER CONDITIONS MIN TYP MAX UNITS
ANALOG INPUT
Full-Scale Input Voltage Range
AINP – AINN ±2V
REF
V
Absolute Input Range AINP, AINN with Respect to GND GND – 0.1
AVDD + 0.1 V
Differential Input Impedance f
CLK
= 2.4576MHz 5 MΩ
SYSTEM PERFORMANCE
Resolution No Missing Codes 24 Bits
Data Rate f
CLK
= 2.4576MHz 15 sps
(1)
Integral Nonlinearity (INL) Differential Input Signal, End Point Fit ±0.0002 ±0.0008 % FSR
(2)
Offset Error 1 10 ppm of FSR
Offset Error Drift
(3)
0.01 ppm of FSR/°C
Gain Error 0.005 0.02 %
Gain Error Drift
(3)
0.5 ppm/°C
Common-Mode Rejection at DC 90 130 dB
f
CM
(4)
= 50 ± 1Hz, f
CLK
= 2.4576MHz 100 dB
f
CM
= 60 ± 1Hz, f
CLK
= 2.4576MHz 100 dB
Normal-Mode Rejection f
SIG
(5)
= 50 ± 1Hz, f
CLK
= 2.4576MHz 60 dB
f
SIG
= 60 ± 1Hz, f
CLK
= 2.4576MHz 70 dB
Input Referred Noise 1 ppm of FSR, rms
Analog Power-Supply Rejection at DC, ∆AVDD = 5% 105 dB
Digital Power-Supply Rejection at DC, ∆DVDD = 5% 100 dB
VOLTAGE REFERENCE INPUT
Reference Input Voltage (V
REF
)V
REF
≡ VREFP – VREFN 0.5 2.5 AVDD
(6)
V
Negative Reference Input (VREFN) GND – 0.1 VREFP – 0.5 V
Positive Reference Input (VREFP) VREFN + 0.5 AVDD + 0.1 V
Voltage Reference Impedance f
CLK
= 2.4576MHz 1 MΩ
DIGITAL INPUT/OUTPUT
Logic Levels
V
IH
(CLK, SCLK) 2.1 5.25 V
V
IL
(CLK, SCLK) GND 0.9 V
V
OH
(
DRDY/DOUT
)I
OH
= 1mA 2.6 V
V
OL
(
DRDY/DOUT
)I
OL
= 1mA 0.4 V
Input Leakage (CLK, SCLK) 0 < (CLK, SCLK) < DVDD ±10 µA
CLK Frequency (f
CLK
) 6MHz
CLK Duty Cycle 30 70 %
POWER SUPPLY
AVDD 2.5 5.25 V
DVDD 1.8 3.6 V
AVDD Current Sleep Mode 0.1 1 µA
AVDD = 3V 85 µA
AVDD = 5V 90 150 µA
DVDD Current Sleep Mode, CLK Stopped 0.1 µA
Sleep Mode, 2.4576MHz CLK Running 1.3 5 µA
DVDD = 3V 4.5 10 µA
Total Power Dissipation AVDD = DVDD = 3V 270 µW
NOTES: (1) sps = Samples Per Second. (2) FSR = Full-Scale Range = 4V
REF
. (3) Recalibration can reduce these errors to the level of the noise. (4) f
CM
is the frequency
of the common-mode input. (5) f
SIG
is the frequency of the input signal. (6) It will not be possible to reach the digital output full-scale code when V
REF
> AVDD/2.