ADC128D818_15 Datasheet, PDF (31/46 Pages) Texas Instruments – ADC System Monitor

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ADC128D818
SNAS483F – FEBRUARY 2010 – REVISED AUGUST 2015
9.1.3.3 Temperature Interrupt
One of the ADC128D818 features is monitoring the temperature reading. This monitoring is accomplished by
setting a temperature limit to the Temperature High Limit Register (T_hot , address 38h) and Temperature
Hysteresis Limit Register (T_{hot_hyst}, address 39h). These limit registers have an interrupt mode, shown in
Figure 35, that operates in the following way: if the temperature reading > T_hot, an interrupt will occur and will
remain active indefinitely until reset by reading the Interrupt Status Register (address 01h) or cleared by the
'INT_Clear' bit.
Once an interrupt event has occurred by crossing T_hot, then reset, an interrupt will occur again once the next
temperature conversion has completed. The interrupts will continue to occur in this manner until the temperature
reading is ≤ T_{hot_hyst} and a read of the Interrupt Status Register has occurred.
Figure 35. Temperature Response Structure
(Assuming the Interrupt Output Pin, INT, is Reset Before the Next Temperature Reading)
9.2 Typical Application
LM94022
V+ VREF
ADC128D818
Single-Ended
Positive Voltage
Internal
VREF = +2.56V
10VIN
Shutdown
Margining
Pseudo-Differential
Positive Voltage
DC-DC
IN0
Interrupt
IN1
Interrupt
Masking
V_OUT
IN2
IN3
IN4 (+)
IN5 (-)
12-bit
Delta-Sigma
ADC
Status
Registers
and
Interrupt
Control
INT
IN7 (+)
IN6 (-)
Voltage
SDA
Temperature
Sensor
I²C Interface and Control
SCL
A0
A1
R_TRACE
GND
Figure 36. Hardware Monitor Application
9.2.1 Design Requirements
In this typical hardware monitor application, several different sources are being monitored by the ADC128D818.
First, an external temperature sensor (LM94022) is being monitored. An external temperature sensor is
frequently used to monitor ambient temperature of the system.
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