Dual Channel Temperature Sensor
and Over Temperature Alarm
ADT7483A
FEATURES
GENERAL DESCRIPTION
1 local and 2 remote temperature sensors
0.25°C resolution/1°C accuracy on remote channels
1°C resolution/1°C accuracy on local channel
Extended, switchable temperature measurement range
0°C to 127°C (default) or –64°C to +191°C
2-wire SMBus serial interface with SMBus alert support
Programmable over/under temperature limits
Offset registers for system calibration
Up to 2 overtemperature fail-safe THERM outputs
Small 16-lead QSOP package
The ADT7483A1 is a three-channel digital thermometer and
under/over temperature alarm, intended for use in PCs and
thermal management systems. It can measure the temperature
in two remote locations, for example, the remote thermal diode
in a CPU or GPU, or a discrete diode connected transistor. It can
also measure its own ambient temperature. The temperature of the
remote thermal diode and ambient temperature can be accurately
measured to 1ꢀC. The temperature measurement range defaults to
0ꢀC to 127ꢀC, compatible with ADM1032, but can be switched
to a wider measurement range, from −64ꢀC to +191ꢀC.
240 μA operating current, 5 μA standby current
The ADT7483A communicates over a 2-wire serial interface
compatible with system management bus (SMBus) standards.
The SMBus address is set by the ADD0 and ADD1 pins. As
many as nine different SMBus addresses are possible.
APPLICATIONS
Desktop and notebook computers
Industrial controllers
Smart batteries
ALERT
An
temperature is outside the programmed limits. The
output is a comparator output that allows, for example, on/off
ALERT
output signals when the on-chip or remote
THERM
Automotive
Embedded systems
Burn-in applications
Instrumentation
control of a cooling fan. The
as a second
output can be reconfigured
output, if required.
THERM
FUNCTIONAL BLOCK DIAGRAM
ADDRESS POINTER
REGISTER
ONE-SHOT
REGISTER
CONVERSION RATE
LOCAL TEMPERATURE
THERM LIMIT REGISTER
REGISTER
ON-CHIP TEMP
SENSOR
LOCAL TEMPERATURE
VALUE REGISTER
LOCAL TEMPERATURE
LOW LIMIT REGISTER
3
4
D1+
D1–
LOCAL TEMPERATURE
HIGH LIMIT REGISTER
ANALOG
MUX
11-BIT A-TO-D
CONVERTER
D2+ 12
REMOTE 1 AND 2 TEMP
THERM LIMIT REGISTER
BUSY RUN/STANDBY
11
D2–
REMOTE 1 AND 2 TEMP
VALUE REGISTERS
REMOTE 1 AND 2 TEMP
LOW LIMIT REGISTERS
REMOTE 1 AND 2 TEMP
HIGH LIMIT REGISTERS
REMOTE 1 AND 2 TEMP
OFFSET REGISTERS
CONFIGURATION
REGISTERS
EXTERNAL DIODES OPEN-CIRCUIT
INTERRUPT
MASKING
13
ALERT/THERM2
STATUS REGISTERS
ADT7483A
SMBus INTERFACE
2
6
14
15
5
16
1
V
GND
SDATA SCLK
ADD0 ADD1
DD
THERM
Figure 1.
1 Protected by U.S. Patents 5,195,827, 5,867,012, 5,982,221, 6,097,239, 6,133,753, 6,169,442, other patents pending.
Rev. 0
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