LTC2494CUHF-PBF LINER [Linear Technology], LTC2494CUHF-PBF Datasheet - Page 30

• Manufacturer Part Number: LTC2494CUHF-PBF
• Description: 16-Bit 8-/16-Channel ?? ADC with PGA and Easy Drive Input Current Cancellation
• Manufacturer: LINER [Linear Technology]

APPLICATIONS INFORMATION
LTC2494
In cases where large bypass capacitors are required on
the reference inputs (C
ity errors are proportional to the value of the reference
resistance. Every ohm of reference resistance produces
a full-scale error of approximately 0.5ppm (while operat-
ing in simultaneous 50Hz/60Hz mode)(see Figures 16
and 17). If the input common mode voltage is equal to
the reference common mode voltage, a linearity error of
approximately 0.67ppm per 100Ω of reference resistance
results (see Figure 18). In applications where the input
and reference common mode voltages are different, the
errors increase. A 1V difference in between common mode
input and common mode reference results in a 6.7ppm
INL error for every 100Ω of reference resistance.
30
Figure 15. –FS Error vs R
Figure 14. +FS Error vs R
–10
–10
–20
–30
–40
–50
–60
–70
–80
–90
90
80
70
60
50
40
30
20
10
10
0
0
0
0
V
V
V
V
F
T
V
V
V
V
F
T
O
O
CC
REF
IN
IN
A
A
CC
REF
IN
IN
= GND
= 25°C
= GND
= 25°C
+
–
+
–
C
= 5V
= 5V
= 3.75V
= 1.25V
= 1.25V
= 3.75V
= 5V
C
C
REF
= 5V
C
REF
C
10
REF
10
REF
C
REF
C
REF
= 0.001μF
REF
C
= 0.01μF
= 0.001μF
REF
= 100pF
= 0.01μF
= 100pF
REF
= 0pF
= 0pF
100
R
100
R
SOURCE
SOURCE
> 0.01μF) full-scale and linear-
SOURCE
SOURCE
(Ω)
(Ω)
1k
1k
at V
at V
10k
10k
REF
REF
2494 F14
2494 F15
(Small C
(Small C
100k
100k
REF
REF
)
)
Figure 18. INL vs Differential Input Voltage and Reference
Source Resistance for C
Figure 16. +FS Error vs R
Figure 17. –FS Error vs R
–100
–400
–200
–300
–500
500
400
200
100
–10
300
10
–2
–4
–6
–8
0
0
8
6
4
2
0
– 0.5
0
0
V
V
V
V
F
T
V
V
V
T
C
V
V
V
V
F
T
O
O
A
CC
REF
IN(CM)
A
REF
CC
REF
IN
IN
A
CC
REF
IN
IN
= GND
= 25°C
= 25°C
= GND
= 25°C
C
+
–
+
–
= 5V
= 5V
= 5V
REF
= 3.75V
= 1.25V
= 1.25V
= 3.75V
= 5V
= 10μF
= 5V
= 5V
– 0.3
200
200
= 2.5V
= 1μF, 10μF
REF
– 0.1
400
400
R
R
V
SOURCE
SOURCE
IN
/V
> 1μF
SOURCE
SOURCE
REF
C
REF
600
600
(Ω)
(Ω)
0.1
(V)
= 1μF, 10μF
C
C
at V
R = 500Ω
at V
R = 100Ω
REF
REF
C
C
R = 1k
REF
REF
800
800
0.3
= 0.01μF
= 0.01μF
REF
REF
= 0.1μF
= 0.1μF
2494 F16
2494 F17
2494 F18
(Large C
(Large C
1000
1000
0.5
REF
REF
)
)
2494fb