LTC2410 Linear Technology, LTC2410 Datasheet - Page 36

• Manufacturer Part Number: LTC2410
• Description: 24-Bit No Latency ADC with Differential Input and Differential Reference
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
LTC2410
The error associated with the 10V excitation would be
–80ppm. Hence, overall reference error could be as high
as 130ppm, the average of the two.
Figure 52 shows a similar scheme to provide excitation
using resistor arrays to produce precise gain. The circuit
is configured to provide 10V and –5V excitation to the
bridge, producing a common mode voltage at the input to
the LTC2410 of 2.5V, maximizing the AC input range for
applications where induced 60Hz could reach amplitudes
up to 2V
The last two example circuits could be used where mul-
tiple bridge circuits are involved and bridge output can be
multiplexed onto a single LTC2410, via an inexpensive
multiplexer such as the 74HC4052.
36
RMS
.
U
PLATINUM
Figure 50. Remote Half Bridge Sensing with Noise Suppression on Reference
100
U
RTD
W
10k, 5%
R1
0.1%
10k
R2
Figure 49. Remote Half Bridge Interface
PLATINUM
10k
U
5%
R3
100
25.5k
0.1%
RTD
R1
1 F
3
4
5
6
Figure 53 shows the use of an LTC2410 with a differential
multiplexer. This is an inexpensive multiplexer that will
contribute some error due to leakage if used directly with
the output from the bridge, or if resistors are inserted as
a protection mechanism from overvoltage. Although the
bridge output may be within the input range of the A/D and
multiplexer in normal operation, some thought should be
given to fault conditions that could result in full excitation
voltage at the inputs to the multiplexer or ADC. The use of
amplification prior to the multiplexer will largely eliminate
errors associated with channel leakage developing error
voltages in the source impedance.
REF
REF
IN
IN
+
–
2.7V TO 5.5V
LTC1050
+
–
LTC2410
+
–
5V
GND
V
V
CC
S
2
1, 7, 8, 9,
10, 15, 16
2410 F49
560
10k
10k
3
4
5
6
REF
REF
IN
IN
+
–
LTC2410
+
–
GND
V
5V
CC
2
1, 7, 8, 9,
10, 15, 16
2410 F50