MAX1618 Datasheet, PDF (1/20 Pages) Maxim Integrated Products – Remote Temperature Sensor with SMBus Serial Interface

19-1495; Rev 1; 10/99
Remote Temperature Sensor
with SMBus Serial Interface
________________General Description
The MAX1618 precise digital thermometer reports the
temperature of a remote sensor. The remote sensor is a
diode-connected transistor—typically a low-cost, easily
mounted 2N3904 NPN type—that replaces conventional
thermistors or thermocouples. Remote accuracy is ±3°C
for multiple transistor manufacturers, with no calibration
needed. The MAX1618 can also measure the die temper-
ature of other ICs, such as microprocessors, that contain
an on-chip, diode-connected transistor.
The 2-wire serial interface accepts standard System
Management Bus (SMBus™) Write Byte, Read Byte, Send
Byte, and Receive Byte commands to program the alarm
thresholds and to read temperature data. The data format
is 7 bits plus sign, with each bit corresponding to 1°C, in
two’s complement format. Measurements can be done
automatically and autonomously, with the 16Hz conversion
rate or programmed to operate in a single-shot mode.
The thermostat mode configures the ALERT output as an
interrupt or as a temperature reset that remains active only
while the temperature is above the maximum temperature
limit or below the minimum temperature limit. The ALERT
output polarity in thermostat mode can be configured for
active high or active low. Fan control is implemented using
this ALERT output.
The MAX1618 is available in a small (1.1mm high) 10-pin
µMAX package.
________________________Applications
Desktop and Notebook
Computers
Central Office
Telecom Equipment
Smart Battery Packs
Test and Measurement
LAN Servers
Multichip Modules
Industrial Controls
___________________Pin Configuration
TOP VIEW
ADD0 1
ADD1 2
GND 3
DXN 4
DXP 5
MAX1618
µMAX
10 ALERT
9 SMBDATA
8 SMBCLK
7 STBY
6 V_CC
____________________________Features
o Single Channel: Measures Remote CPU
Temperature
o No Calibration Required
o SMBus 2-Wire Serial Interface
o Programmable Under/Overtemperature Alarms
o Overtemperature Output for Fan Control
(Thermostat Mode)
o Supports SMBus Alert Response Accuracy
±3°C (+60°C to +100°C)
±5°C (-55°C to +120°C)
o 3µA (typ) Standby Supply Current
o 900µA (max) Supply Current in Autoconvert Mode
o +3V to +5.5V Supply Range
o Small 10-Pin µMAX Package
PART
MAX1618MUB
Ordering Information
TEMP. RANGE
-55°C to +125°C
PIN-PACKAGE
10 µMAX
2N3904
Typical Operating Circuit
0.1µF
3V TO 5.5V
200Ω
V_CC STBY
MAX1618
DXP
SMBCLK
SMBDATA
DXN
2200pF
ALERT
ADD0 ADD1 GND
10k EACH
CLOCK
DATA
INTERRUPT
TO µC
SMBus is a trademark of Intel Corp.
†Patents Pending
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