Datasheet

ADS1258
www.ti.com SBAS297G –JUNE 2005– REVISED MARCH 2011
ELECTRICAL CHARACTERISTICS
All specifications at T
A
= –40°C to +105°C, AVDD = +2.5V, AVSS = –2.5V, DVDD = +3.3V, V
REF
= +4.096V, VREFN = –2.5V,
f
CLK
= 16MHz (external clock) or f
CLK
= 15.729MHz (internal clock), and OPA227 buffer between MUX outputs and ADC
inputs, unless otherwise noted.
ADS1258
TEST
PARAMETER CONDITIONS MIN TYP MAX UNIT
ANALOG MULTIPLEXER INPUTS
AIN0–AIN15,
Absolute Input Voltage AVSS – 100mV AVDD + 100mV V
AINCOM with respect to DGND
On-Channel Resistance 80 Ω
Crosstalk f
IN
= 1kHz –110 dB
SBCS[1:0] = 01 1.5
Sensor Bias (Current Source) μA
SBCS[1:0] = 11 24
1.5μA:24μA Ratio Error 1 %
ADC INPUT
Full-Scale Input Voltage (V
IN
= ADCINP – ADCINN) ±1.06 V
REF
V
Absolute Input Voltage (ADCINP, ADCINN) AVSS – 100mV AVDD + 100mV V
Differential Input Impedance 65 kΩ
SYSTEM PERFORMANCE
Resolution No Missing Codes 24 Bits
Data Rate, Fixed-Channel Mode 1.953 125 kSPS
Data Rate, Auto-Scan Mode 1.805 23.739 kSPS
Integral Nonlinearity (INL)
(1)
Differential Input 0.0003 0.0010 % of FSR
(2)
Chopping Off 20
Offset Error Shorted Inputs μV
Chopping On 1 10
Chopping Off 0.5
Offset Drift
(3)
Shorted Inputs μV/°C
Chopping On 0.02 0.1
Gain Error 0.1 0.5 %
Gain Drift
(3)
0.4 2 ppm/°C
Noise (see Table 6)
Common-Mode Rejection f
CM
= 60Hz 90 100 dB
AVDD, AVSS 70 85
Power-Supply Rejection f
PS
= 60Hz dB
DVDD 80 95
VOLTAGE REFERENCE INPUT
Reference Input Voltage (V
REF
= VREFP – VREFN) 0.5 4.096 AVDD – AVSS V
Negative Reference Input (VREFN) AVSS – 0.1V VREFP – 0.5 V
Positive Reference Input (VREFP) VREFN + 0.5 AVDD + 0.1V V
Reference Input Impedance 40 kΩ
SYSTEM PARAMETERS
External Reference Reading Error 1 3 %
Analog Supply Reading Error 1 3 %
Voltage T
A
= +25°C
(4)
168 mV
Temperature Sensor Reading See note
(4)
394 μV/°C
Coefficient
See note
(5)
563 μV/°C
(1) Best straight line fit method.
(2) FSR = Full-scale range = 2.13V
REF
.
(3) Ensured by characterization.
(4) Only ADS1258 temperature forced; test PCB in free-air.
(5) ADS1258 and test PCB temperatures forced together.
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