Datasheet

I C
2
Interface
MUXOUT
SAR
ADC
ADCIN
AGND AGND
AVDD DVDD
CH0Data
CH1Data
CH2Data
CH3Data
CH0UpperLimit
CH1UpperLimit
CH2UpperLimit
CH3UpperLimit
CH0LowerLimit
CH1LowerLimit
CH2LowerLimit
CH3LowerLimit
Comparatorand
AlarmDetect
Control
and
Sequencer
ClockOscillator
SDA
SCL
RESET
PWRCON
A0
INT
Input
Multiplexer
CH0
CH1
CH2
CH3
Registers
ADS7924
www.ti.com SBAS482A –JANUARY 2010–REVISED MAY 2010
OVERVIEW
The ADS7924 is a miniature, four-channel, multiplexed, 12-bit, analog-to-digital converter (ADC) with an I
2
C
serial interface. Figure 19 shows a block diagram. The four-channel input multiplexer is routed through external
pins to allow a common signal conditioning block to be used for all four channels. The PWRCON digital output
can be used to shut down active circuitry used in the signal conditioning; see the Application Information section
for additional details.
The successive-approximation-register (SAR) ADC performs a no-latency conversion on the selected input
channel and stores the data in a dedicated register. A digital threshold comparator with programmable upper and
lower limits can be enabled and used to create an alarm monitor. A dedicated interrupt output pin (INT) indicates
when an alarm occurs. Two I
2
C addresses are available and are selected with the dedicated digital input pin A0.
Both standard and fast mode formats for I
2
C are supported.
Figure 19. ADS7924 Block Diagram
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