Datasheet

ADS1240, 1241
21
SBAS173F
www.ti.com
APPLICATION EXAMPLES
GENERAL-PURPOSE WEIGH SCALE
Figure 8 shows a typical schematic of a general-purpose
weigh scale application using the ADS1240. In this example,
the internal PGA is set to either 64 or 128 (depending on the
maximum output voltage of the load cell) so that the load cell
ADS1240
V
REF+
AV
DD
DRDY
SCLK
D
OUT
D
OUT
CS
X
IN
DV
DD
AGND DGND
A
IN
0
V
DD
2.7V ~ 5.25V
GND
MCLK
A
IN
1
EMI Filter
Load Cell
MSP430x4xx
or other µP
V
REF–
SPI
X
OUT
2.7V ~ 5.25V
EMI Filter
EMI Filter
EMI Filter
output can be directly applied to the differential inputs of
ADS1240.
HIGH PRECISION WEIGH SCALE
Figure 9 shows the typical schematic of a high-precision
weigh scale application using the ADS1240. The front-end
differential amplifier helps maximize the dynamic range.
ADS1240
ADS1241
V
REF+
AV
DD
DRDY
SCLK
D
OUT
D
IN
CS
X
IN
DV
DD
AGND DGND
A
IN
0
V
DD
2.7V ~ 5.25V
GND
MCLK
A
IN
1
EMI Filter
EMI Filter
Load Cell
OPA2335
G = 1 + 2 • R
F
/R
G
MSP430x4xx
or other µP
V
REF–
SPI
X
OUT
2.7V ~ 5.25V
EMI Filter
EMI Filter
OPA2335
R
F
C
I
R
G
R
F
R
I
R
I
FIGURE 8. Schematic of a General-Purpose Weigh Scale.
FIGURE 9. Block Diagram for a High-Precision Weigh Scale.