Datasheet

TLV2780
RESET
INT
SCL
SDA
CH0
CH1
CH2
CH3
1
2
3
4
12
11
10
9
DVDD
16
A0
5
AVDD
15
DGND
6
ADCIN
14
PWRCON
7
MUXOUT
13
AGND
8
ADS7924
SensorSignals
MSP430
Microcontroller
SHDN
DVDD
AVDD
1 Fm
1 Fm
3kW 3kW
ADS7924
www.ti.com SBAS482A –JANUARY 2010–REVISED MAY 2010
BASIC CONNECTIONS
The ADS7924 provides a break-out point in the signal path between the multiplexer output and the ADC input for
external signal conditioning, if desired. Typical uses include adding an op amp, such as the TLV2780, along with
an RC filter circuit.
Using an Op Amp
Adding an op amp provides a high input impedance to the sensor source and buffers the capacitive ADC input
from high-impedance sensor circuits, as shown in Figure 35. Note that high-impedance input signals can be
momentarily disrupted when coupled directly to a capacitive input like that of a sampling ADC. This disruption
can create errors when sampling. The use of an op amp is recommended in these cases.
Figure 35. Sensor Data Acquisition with TLV2780 Buffer Amplifier
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Product Folder Link(s): ADS7924