MAX1668 Datasheet, PDF (1/17 Pages) Maxim Integrated Products – Multichannel Remote/Local Temperature Sensors

19-1766; Rev 2; 5/03
Multichannel Remote/Local
Temperature Sensors
________________General Description
The MAX1668/MAX1805/MAX1989 are precise multi-
channel digital thermometers that report the tempera-
ture of all remote sensors and their own packages. The
remote sensors are diode-connected transistors—typi-
cally low-cost, easily mounted 2N3904 NPN types—that
replace conventional thermistors or thermocouples.
Remote accuracy is ±3°C for multiple transistor manu-
facturers, with no calibration needed. The remote chan-
nels can also measure the die temperature 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 for-
mat is 7 bits plus sign, with each bit corresponding to
1°C, in two’s-complement format.
The MAX1668/MAX1805/MAX1989 are available in
small, 16-pin QSOP surface-mount packages. The
MAX1989 is also available in a 16-pin TSSOP.
________________________Applications
Desktop and Notebook
Computers
Central-Office Telecom
Equipment
LAN Servers
Test and Measurement
Industrial Controls
Multichip Modules
____________________________Features
o Multichannel
4 Remote, 1 Local (MAX1668/MAX1989)
2 Remote, 1 Local (MAX1805)
o No Calibration Required
o SMBus 2-Wire Serial Interface
o Programmable Under/Overtemperature Alarms
o Supports SMBus Alert Response
o Accuracy
±2°C (+60°C to +100°C, Local)
±3°C (-40°C to +125°C, Local)
±3°C (+60°C to +100°C, Remote)
o 3µA (typ) Standby Supply Current
o 700µA (max) Supply Current
o Small, 16-Pin QSOP/TSSOP Packages
_______________Ordering Information
PART
MAX1668MEE
MAX1805MEE
MAX1989MEE
MAX1989MUE
TEMP RANGE
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
PIN-PACKAGE
16 QSOP
16 QSOP
16 QSOP
16 TSSOP
Pin Configuration
TOP VIEW
DXP1 1
DXN1 2
DXP2 3
DXN2 4
(N.C.) DXP3 5
(N.C.) DXN3 6
(N.C.) DXP4 7
(N.C.) DXN4 8
MAX1668
MAX1805
MAX1989
16 GND
15 STBY
14 SMBCLK
13 SMBDATA
12 ALERT
11 ADD0
10 ADD1
9 V_CC
( ) ARE FOR MAX1805.
QSOP/TSSOP
Typical Operating Circuit
0.1µF
3V TO 5.5V
200Ω
2200pF
*
2200pF
*
V_CC STBY
MAX1668
MAX1805
MAX1989
DXP1
SMBCLK
DXN1
SMBDATA
ALERT
DXP4
DXN4
ADD0 ADD1 GND
10kΩ EACH
CLOCK
DATA
INTERRUPT
TO µC
* DIODE-CONNECTED TRANSISTOR
SMBus is a trademark of Intel Corp.
†Patents Pending
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.