Datasheet

XTR105
11
SBOS061B
www.ti.com
TABLE II. Error Calculation.
SAMPLE ERROR CALCULATION
RTD value at 4mA Output (R
RTD MIN
): 100Ω
RTD Measurement Range: 200°C
Ambient Temperature Range (∆T
A
): 20°C
Supply Voltage Change (∆V+): 5V
Common-Mode Voltage Change (∆CM): 0.1V
SAMPLE
ERROR SOURCE ERROR EQUATION ERROR CALCULATION
(1)
UNADJ. ADJUST.
INPUT
Input Offset Voltage V
OS
/(V
IN MAX
) • 10
6
100µV/(800µA • 0.38Ω/°C • 200°C) • 10
6
1645 0
vs Common-Mode CMRR • ∆CM/(V
IN MAX
) • 10
6
50µV/V • 0.1V/(800µA • 0.38Ω/°C • 200°C) • 10
6
82 82
Input Bias Current I
B
/I
REF
• 10
6
0.025µA/800µA • 10
6
31 0
Input Offset Current I
OS
• R
RTD MIN
/(V
IN MAX
) • 10
6
3nA • 100Ω/(800µA • 0.38Ω/°C • 200°C) • 10
6
50
Total Input Error: 1763 82
EXCITATION
Current Reference Accuracy I
REF
Accuracy (%)/100% • 10
6
0.2%/100% • 10
6
2000 0
vs Supply (I
REF
vs V+) • ∆V+ 25ppm/V • 5V 125 125
Current Reference Matching I
REF
Matching (%)/100% • 800µA • 0.1%/100% • 800µA • 100Ω/(800µA • 0.38Ω/°C • 200°C) • 10
6
1316 0
R
RTD MIN
/(V
IN MAX
) • 10
6
vs Supply (I
REF
Matching vs V+) • ∆V+ • 10ppm/V • 5V • 800µA • 100Ω/(800µA • 0.38Ω/°C • 200°C) 66 66
R
RTD MIN
/(V
IN MAX
)
Total Excitation Error: 3507 191
GAIN
Span Span Error (%)/100% • 10
6
0.2%/100% • 10
6
2000 0
Nonlinearity Nonlinearity (%)/100% • 10
6
0.01%/100% • 10
6
100 100
Total Gain Error: 2100 100
OUTPUT
Zero Output (I
ZERO
– 4mA) /16000µA • 10
6
25µA/16000µA • 10
6
1563 0
vs Supply (I
ZERO
vs V+) • ∆V+/16000µA • 10
6
0.2µA/V • 5V/16000µA • 10
6
63 63
Total Output Error: 1626 63
DRIFT (∆T
A
= 20 ° C)
Input Offset Voltage Drift • ∆T
A
/(V
IN MAX
) • 10
6
1.5µV/°C • 20°C/(800µA • 0.38Ω/°C • 200°C) • 10
6
493 493
Input Bias Current (typical) Drift • ∆T
A
/800µA • 10
6
20pA/°C • 20°C/800µA • 10
6
0.5 0.5
Input Offset Current (typical) Drift • ∆T
A
• R
RTD MIN
/(V
IN MAX
) • 10
6
5pA/°C • 20°C • 100W/(800µA • 0.38Ω/°C • 200°C) • 10
6
0.2 0.2
Current Reference Accuracy Drift • ∆T
A
35ppm/°C • 20°C 700 700
Current Reference Matching Drift • ∆T
A
• 800µA • R
RTD MIN
/(V
IN MAX
) 15ppm/°C • 20°C • 800µA • 100Ω/(800µA • 0.38Ω/°C • 200°C) 395 395
Span Drift • ∆T
A
25ppm/°C • 20°C 500 500
Zero Output Drift • ∆T
A
/16000µA • 10
6
0.5µA/°C • 20°C/16000µA • 10
6
626 626
Total Drift Error: 2715 2715
NOISE (0.1Hz to 10Hz, typ)
Input Offset Voltage v
n
/(V
IN MAX
) • 10
6
0.6µV/(800µA • 0.38Ω/°C • 200°C) • 10
6
10 10
Current Reference I
REF
Noise • R
RTD MIN
/(V
IN MAX
) • 10
6
3nA • 100Ω/(800µA • 0.38Ω/°C • 200°C) • 10
6
55
Zero Output I
ZERO
Noise/16000µA • 10
6
0.03µA/16000µA • 10
6
22
Total Noise Error: 17 17
TOTAL ERROR: 11728 3168
(1.17%) (0.32%)
ERROR
(ppm of Full Scale)
NOTE (1): All errors are min/max and referred to input unless otherwise stated.