DS1620 Digital Thermometer and Thermostat BENEFITS AND FEATURES PIN ASSIGNMENT Simply Adds Temperature Monitoring and 8 DQ 1 V DD Control to Any System 2 7 o Measures Temperatures From -55C to C LK/CONV T HIGH +125C in 0.5C Increments Fahrenheit 6 RST 3 T LOW Equivalent is -67F to +257F in 0.9F 4 5 Increments GND T COM o Temperature is Read as a 9-Bit Value DS1620S 8-Pin SOIC (208-mil) o Converts Temperature to Digital Word in 750ms (max) o Thermostatic Settings are User-Definable 8 DQ 1 V DD and Nonvolatile Can Be Used in a Wide Variety of 2 7 CLK/CONV T HIGH Applications 3 6 RST T LOW o Supply Voltage Range Covers From 2.7V to 5.5V 5 4 GND T COM o Data is Read From/Written Via a 3-Wire DS1620 8-Pin DIP (300-mil) Serial Interface (CLK, DQ, RST ) Saves Space o Requires No External Components PIN DESCRIPTION o 8-Pin DIP or SOIC (208-mil) Packages DQ - 3-Wire Input/Output CLK/ CONV - 3-Wire Clock Input and Stand-alone Convert Input APPLICATIONS RST - 3-Wire Reset Input Thermostatic Controls GND - Ground Industrial Systems T - High Temperature Trigger HIGH Consumer Products T - Low Temperature Trigger LOW Thermometers T - High/Low Combination Trigger COM V - Power Supply Voltage (3V - 5V) DD DESCRIPTION The DS1620 Digital Thermometer and Thermostat provides 9bit temperature readings which indicate the temperature of the device. With three thermal alarm outputs, the DS1620 can also act as a thermostat. T is driven high if the DS1620s temperature is greater than or equal to a userdefined temperature HIGH TH. T is driven high if the DS1620s temperature is less than or equal to a userdefined temperature LOW TL. T is driven high when the temperature exceeds TH and stays high until the temperature falls COM below that of TL. 1 of 12 19-7539 Rev 3 3/15 DS1620 Userdefined temperature settings are stored in nonvolatile memory, so parts can be programmed prior to insertion in a system, as well as used in standalone applications without a CPU. Temperature settings and temperature readings are all communicated to/from the DS1620 over a simple 3wire interface. ORDERING INFORMATION PART PACKAGE MARKING DESCRIPTION DS1620 DS1620 8-Pin DIP (300 mil) DS1620+ DS1620 (See Note) Lead-Free 8-Pin DIP (300 mil) DS1620S DS1620 8-Pin SOIC (208 mil) DS1620S+ DS1620 (See Note) Lead-Free 8-Pin SOIC (208 mil) DS1620S/T&R DS1620 8-Pin SOIC (208 mil), 2000-Piece Tape-and-Reel DS1620S+T&R DS1620 (See Note) Lead-Free 8-Pin SOIC (208 mil), 2000-Piece Tape-and-Reel Note: A + symbol will also be marked on the package near the Pin 1 indicator DETAILED PIN DESCRIPTION Table 1 PIN SYMBOL DESCRIPTION 1 DQ Data Input/Output pin for 3-wire communication port. 2 Clock input pin for 3-wire communication port. When the DS1620 is used in a CLK/ CONV stand-alone application with no 3wire port, this pin can be used as a convert pin. Temperature conversion will begin on the falling edge of CONV . 3 Reset input pin for 3-wire communication port. RST 4 GND Ground pin. 5 T High/Low Combination Trigger. Goes high when temperature exceeds TH COM will reset to low when temperature falls below TL. 6 T Low Temperature Trigger. Goes high when temperature falls below TL. LOW 7 T High Temperature Trigger. Goes high when temperature exceeds TH. HIGH 8 V Supply Voltage. 2.7V 5.5V input power pin. DD Table 2. DS1620 REGISTER SUMMARY REGISTER NAME MEMORY REGISTER CONTENTS SIZE (USER ACCESS) TYPE AND POWER-UP/POR STATE Temperature Measured Temperature (Twos Complement) 9 Bits SRAM (Read Only) Power-Up/POR State: -60C (1 1000 1000) Upper Alarm Trip Point (Twos Complement) T H 9 Bits EEPROM Power-Up/POR State: User-Defined. (Read/Write) Initial State from Factory: +15C (0 0001 1110) Lower Alarm Trip Point (Twos Complement) T L 9 Bits EEPROM Power-Up/POR State: User-Defined. (Read/Write) Initial State from Factory: +10C (0 0001 0100) OPERATION-MEASURING TEMPERATURE A block diagram of the DS1620 is shown in Figure 1 . 2 of 12