A
V
AI
LA
B
LE
or pricing, delivery, and ordering information, please contact Maxim Direct
1-
-  2  -4  42   r vi  i  M  xim  w
i
www.m  ximin    r
.   m.
     
102307
FEATURES
  DS1631 and DS1631A Provide ?.5癈
Accuracy over a 0癈 to +70癈 Range
  DS1731 Provides ?癈 Accuracy over a
-10癈 to +85癈 Range
  DS1631A Automatically Begins Taking
Temperature Measurements at Power-Up
  Operating Temperature Range: -55癈 to
+125癈 (-67癋 to +257癋)
  Temperature Measurements Require No
External Components
  Output Resolution is User-Selectable to 9,
10, 11, or 12 Bits
  Wide Power-Supply Range (+2.7V to +5.5V)
  Converts Temperature-to-Digital Word in
750ms (max)
  Multidrop Capability Simplifies Distributed
Temperature-Sensing Applications
  Thermostatic Settings are User-Definable
and Nonvolatile (NV)
  Data is Read/Written Through 2-Wire Serial
Interface (SDA and SCL Pins)
  All Three Devices are Available in 8-Pin
糞OP Packages and the DS1631 is Also
Available in a 150mil SO packagesee
Table 1 for Ordering Information
PIN CONFIGURATIONS
DESCRIPTION
The DS1631, DS1631A, and DS1731 digital thermometers provide 9, 10, 11, or 12-bit temperature
readings over a -55癈 to +125癈 range. The DS1631 and DS1631A thermometer accuracy is ?.5癈
from 0癈 to +70癈 with 3.0V d V
DD
d 5.5V, and the DS1731 accuracy is ?癈 from -10癈 to +85癈 with
3.0V d V
DD
d 5.5V. The thermostat on all three devices provides custom hysteresis with user-defined trip
points (T
H
and T
L
). The T
H
and T
L
registers and thermometer configuration settings are stored in NV
EEPROM so they can be programmed prior to installation. In addition, the DS1631A automatically
begins taking temperature measurements at power-up, which allows it to function as a stand-alone
thermostat. Communication with the DS1631/DS1631A/DS1731 is achieved through a 2-wire serial
interface, and three address pins allow up to eight devices to be multidropped on the same 2-wire bus.
Pin descriptions for the DS1631/DS1631A/DS1731 are provided in Table 2 and user-accessible registers
are summarized in Table 3. A functional diagram is shown in Figure 1.
DS1631/DS1631A/DS1731
High-Precision Digital
Thermometer and Thermostat
SO (150mil and 208mil)
(DS1631Z+, DS1631S+)
L
V
DD
A
0
A
1
A
2
GND
T
OUT
D
6
7
3
2
SOP
(DS1631U+, DS1631AU+,
DS1731U+)
L
V
DD
A
0
A
1
A
2
GND
T
OUT
D
6
7
3
2
See Table 2 for Pin Descriptions
APPLICATIONS
  Network Routers and Switches
  Cellular Base Stations
  Portable Products
  Any Space-Constrained Thermally Sensitive
Product