
LTC2414/LTC2418
40
241418fa
350
BRIDGE
0.1
F
1
F
15V
–15V
38
14
7
4
13
12
11
10V
5V
15V
U1
LTC1043
6
2
7
4
7
4
–
+
REF+
REF–
CH0
CH1
GND
VCC
11
12
21
22
15
2410 F52
9
5V
LTC2414/
LTC2418
47
F
0.1
F
10V
+
17
5
15
6
18
3
2
U2
LTC1043
1
F
FILM
8
14
7
4
13
12
11
*
5V
U2
LTC1043
17
–10V
LT1236-5
1k
33
Q1
2N3904
0.1
F
15V
–15V
3
6
2
–
+
1k
33
–10V
10V
Q2
2N3906
*FLYING CAPACITORS ARE
1
F FILM (MKP OR EQUIVALENT)
SEE LTC1043 DATA SHEET FOR
DETAILS ON UNUSED HALF OF U1
LTC1150
20
200
20
200
0.1
F
10
F
+
Figure 46. LTC1043 Provides Precise 4X Reference for Excitation Voltages
APPLICATIO S I FOR ATIO
WU
UU
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 47 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 LTC2414/LTC2418 of 2.5V, maximizing the AC input
range for applications where induced 60Hz could reach
amplitudes up to 2VRMS.