Document
DS1626/DS1726
High-Precision 3-Wire Digital Thermometer and Thermostat
www.maxim-ic.com
DESCRIPTION
The DS1626 and DS1726 digital thermometers/thermostats provide temperature measurements and stand-alone thermostat capability over a -55°C to +125°C range. The DS1626 offers ±0.5°C accuracy from 0°C to +70°C and the DS1726 has ±1°C accuracy from -10°C to +85°C. The resolution of the measured temperature is user selectable from 9 to 12 bits. Communication with the DS1626 and DS1726 is achieved through a 3-wire serial bus.
The DS1626 and DS1726 offer thermostatic functionality with three dedicated thermostat outputs (THIGH, TLOW, and TCOM), and overtemperature (TH) and undertemperature (TL) user-programmable thresholds stored in on-chip EEPROM. For stand-alone thermostat operation, TH and TL can be programmed prior to installation, and the DS1626/DS1726 can be configured to automatically begin taking temperature measurements at power-up. Table 1 summarizes the user-accessible registers. Figure 1 shows a functional diagram.
APPLICATIONS
Thermostatic Controls Industrial Controls Consumer Products Any Space-Constrained Thermally Sensitive
Application
FEATURES
Temperature Measurements Require No External Components Measure Temperatures from -55°C to +125°C (-67°F to +257°F) DS1626: ±0.5°C Accuracy from 0°C to +70°C DS1726: ±1°C Accuracy from -10°C to +85°C Output Resolution is User Selectable to 9, 10, 11, or 12 Bits Wide Power-Supply Range (2.7V to 5.5V) Convert Temperature to Digital Word in 750ms (max) Stand-Alone Thermostat Capability Thermostatic Settings are User Definable and Nonvolatile (NV) Data is Read/Written Through a 3-Wire Serial Interface Available in 8-Pin μSOP Package
PIN CONFIGURATION
TOP VIEW
DQ CLK/CNV
RST GND
1
8
DS1626
2 DS1726 7
3
6
4
5
VDD THIGH TLOW TCOM
μSOP
ORDERING INFORMATION
PART
TEMP RANGE
DS1626U
-55°C to +125°C
DS1626U+
-55°C to +125°C
DS1626U/T&R
-55°C to +125°C
DS1626U+T&R
-55°C to +125°C
DS1726U
-55°C to +125°C
DS1726U+
-55°C to +125°C
DS1726U/T&R
-55°C to +125°C
DS1726U+T&R
-55°C to +125°C
PIN-PACKAGE 8 μSOP 8 μSOP 8 μSOP, 3000-Piece 8 μSOP, 3000-Piece 8 μSOP 8 μSOP 8 μSOP, 3000-Piece 8 μSOP, 3000-Piece
+Denotes a lead-free package. A “+” symbol will also be marked on the package near the Pin 1 indicator. T&R = Tape and reel.
TOP MARK 1626 1626 1626 1626 1726 1726 1726 1726
1 of 12
REV: 071107
DS1626/DS1726
PIN DESCRIPTION
PIN NAME
FUNCTION
1
DQ Data Input/Output Pin (Tri-State) for 3-Wire Serial Communication
2
CLK/CNV
Clock Input Pin for 3-Wire Serial Communication. Controls temperature measurements when the DS1626/DS1726 is configured as a stand-alone thermostat.
3
RST Reset Input Pin for 3-Wire Serial Communication
4
GND Ground Pin
5
TCOM Thermostat Output Pin (Push-Pull) with Programmable Hysteresis
6
TLOW Thermostat Output Pin (Push-Pull) with TL Trip Point
7
THIGH Thermostat Output Pin (Push-Pull) with TH Trip Point
8
VDD Supply Voltage. +2.7V to +5.5V i.