LTC2431CMS#TRPBF Linear Technology, LTC2431CMS#TRPBF Datasheet - Page 36

• Manufacturer Part Number: LTC2431CMS#TRPBF
• Description: IC ADC 20BIT DIFFINPUT/REF10MSOP
• Manufacturer: Linear Technology

Specifications of LTC2431CMS#TRPBF

• Number Of Bits: 20
• Sampling Rate (per Second): 7.5
• Data Interface: MICROWIRE™, Serial, SPI™
• Number Of Converters: 2
• Power Dissipation (max): 1mW
• Voltage Supply Source: Single Supply
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIO S I FOR ATIO
LTC2430/LTC2431
The circuit shown in Figure 42 shows a more rigorous
example of Figure 41, with increased noise suppression
and more protection for remote applications.
Figure 43 shows an example of gain in the excitation circuit
and remote feedback from the bridge. The LTC1043s
provide voltage multiplication, providing 10V from a 5V
reference with only 1ppm error. The amplifiers are used at
unity-gain and, hence, introduce a very little error due to
gain error or due to offset voltages. A 1 V/ C offset voltage
36
BRIDGE
350
2N3904
2N3906
33
10V
Q1
Q2
U
–15V
15V
–10V
33
20
20
U
1k
Figure 43. LTC1043 Provides Precise 4 Reference for Excitation Voltages
1k
6
6
0.1 F
0.1 F
W
LTC1150
LTC1150
–15V
–15V
15V
7
4
15V
7
4
+
–
+
–
3
2
3
2
U
1 F
FILM
10V
1 F
–10V
200
200
drift translates into 0.05ppm/ C gain error. Simpler alter-
natives, with the amplifiers providing gain using resistor
arrays for feedback, can produce results that are similar to
bridge sensing schemes via attenuators. Note that the
amplifiers must have high open-loop gain or gain error will
be a source of error. The fact that input offset voltage has
relatively little effect on overall error may lead one to use
low performance amplifiers for this application. Note that
the gain of a device such as an LF156, (25V/mV over
14
8
15
14
U1
LTC1043
5
8
11
12
U2
LTC1043
U2
LTC1043
11
12
2
3
*
15V
–10V
*
*
4
17
5V
4
17
7
13
6
18
7
13
47 F
2431 F43
0.1 F
10 F
*FLYING CAPACITORS ARE
1 F FILM (MKP OR EQUIVALENT)
SEE LTC1043 DATA SHEET FOR
DETAILS ON UNUSED HALF OF U1
+
5V
REF
REF
IN
IN
LT1236-5
+
–
LTC2430/
LTC2431
+
–
GND
V
CC
0.1 F
10V
5V
24301f