The MAX6604 high-precision temperature sensor is designed for thermal monitoring functions in DDR memory modules. The device is readable and programmable through the 2-wire SMBus/I²C-compatible interface. Three address inputs set the bus address for the temperature sensor to provide up to eight devices on one bus.The internal thermal sensor continuously monitors the temperature and updates the temperature data eight times per second. The master can read the temperature data at any time. Since the thermal sensor is located on the memory module, temperature data recorded accurately represents the temperature of the components on the module. Consequently, the MAX6604 provides a much more accurate measurement of module temperature than techniques involving temperature sensors on the motherboard. In addition, the device responds more quickly to temperature changes on the module than a motherboard sensor.The MAX6604 also features an interrupt-output indicator for temperature-threshold monitoring. The threshold levels are programmable through the digital interface.The MAX6604 operates from -20°C to +125°C, and is available in JEDEC-standard 8-pin TSSOP and 8-pin TDFN (2mm x 3mm) packages.ApplicationsDesktop ComputersMemory ModulesNetworking EquipmentNotebook ComputersWorkstations

The MAX6689 precision multichannel temperature sensor monitors its own temperature and the temperatures of up to six external diode-connected transistors. All temperature channels have programmable alert thresholds. Channels 1, 4, 5, and 6 also have programmable overtemperature thresholds. When the measured temperature of a channel exceeds the respective threshold, a status bit is set in one of the status registers. Two open-drain outputs, active-low OVERT and active-low ALERT, assert corresponding to these bits in the status register.The 2-wire serial interface supports the standard system management bus (SMBus™) protocols: write byte, read byte, send byte, and receive byte for reading the temperature data and programming the alarm thresholds.The MAX6689 is specified for an operating temperature range of -40°C to +125°C and is available in 20-pin QSOP and TSSOP packages.ApplicationsDesktop ComputersNotebook ComputersServersWorkstations

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, in the full data sheet, summarizes the user-accessible registers. Figure 1, in the full data sheet, shows a functional diagram.ApplicationsAny Space-Constrained Thermally Sensitive ApplicationConsumer ProductsIndustrial ControlsThermostatic Controls

The DS18S20 digital thermometer provides 9-bit Celsius temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18S20 communicates over a 1-Wire® bus that by definition requires only one data line (and ground) for communication with a central microprocessor. In addition, the DS18S20 can derive power directly from the data line ('parasite power'), eliminating the need for an external power supply.Each DS18S20 has a unique 64-bit serial code, which allows multiple DS18S20s to function on the same 1-Wire bus. Thus, it is simple to use one microprocessor to control many DS18S20s distributed over a large area. Applications that can benefit from this feature include HVAC environmental controls, temperature monitoring systems inside buildings, equipment, or machinery, and process monitoring and control systems.ApplicationsConsumer ProductsIndustrial SystemsThermally Sensitive SystemsThermometersThermostatic Controls

The DS75 digital thermometer and thermostat provides 9, 10, 11, or 12-bit digital temperature readings over a -55°C to +125°C range with ±2°C accuracy over a -25°C to +100°C range. At power-up, the DS75 defaults to 9-bit resolution for software compatibility with the LM75. Communication with the DS75 is achieved via a simple 2-wire serial interface. Three address pins allow up to eight DS75 devices to operate on the same 2-wire bus, which greatly simplifies distributed temperature sensing applications. The DS75 thermostat has a dedicated open-drain output (O.S.) and programmable fault tolerance, which allows the user to define the number of consecutive error conditions that must occur before O.S is activated. There are two thermostatic operating modes that control thermostat operation based on user-defined trip-points (TOS and THYST).A block diagram of the DS75 is shown in Figure 1 and detailed pin descriptions are given in Table 2.ApplicationsAny Thermally Sensitive SystemCell Phone Base Stations Office EquipmentPersonal Computing

The AD590 is a two-terminal integrated circuit temperature transducer that produces an output current proportional to absolute temperature. For supply voltages between 4 V and 30 V the device acts as a high impedance, constant current regulator passing 1 µA/K. Laser trimming of the chip's thin-film resistors is used to calibrate the device to 298.2 µA output at 298.2K (25°C).The AD590 should be used in any temperature sensing application below 150°C in which conventional electrical temperature sensors are currently employed. The inherent low cost of a monolithic integrated circuit combined with the elimination of support circuitry makes the AD590 an attractive alternative for many temperature measurement situations. Linearization circuitry, precision voltage amplifiers, resistance measuring circuitry and cold junction compensation are not needed in applying the AD590.In addition to temperature measurement, applications include temperature compensation or correction of discrete components, biasing proportional to absolute temperature, flow rate measurement, level detection of fluids and anemometry.The AD590 is particularly useful in remote sensing applications. The device is insensitive to voltage drops over long lines due to its high impedance current output. Any well insulated twisted pair is sufficient for operation hundreds of feet from the receiving circuitry. The output characteristics also make the AD590 easy to multiplex: the current can be switched by a CMOS multiplexer or the supply voltage can be switched by a logic gate output.

The AD590 is a two-terminal integrated circuit temperature transducer that produces an output current proportional to absolute temperature. For supply voltages between 4 V and 30 V the device acts as a high impedance, constant current regulator passing 1 µA/K. Laser trimming of the chip's thin-film resistors is used to calibrate the device to 298.2 µA output at 298.2K (25°C).The AD590 should be used in any temperature sensing application below 150°C in which conventional electrical temperature sensors are currently employed. The inherent low cost of a monolithic integrated circuit combined with the elimination of support circuitry makes the AD590 an attractive alternative for many temperature measurement situations. Linearization circuitry, precision voltage amplifiers, resistance measuring circuitry and cold junction compensation are not needed in applying the AD590.In addition to temperature measurement, applications include temperature compensation or correction of discrete components, biasing proportional to absolute temperature, flow rate measurement, level detection of fluids and anemometry.The AD590 is particularly useful in remote sensing applications. The device is insensitive to voltage drops over long lines due to its high impedance current output. Any well insulated twisted pair is sufficient for operation hundreds of feet from the receiving circuitry. The output characteristics also make the AD590 easy to multiplex: the current can be switched by a CMOS multiplexer or the supply voltage can be switched by a logic gate output.

The MAX31722/MAX31723 digital thermometers and thermostats with an SPI/3-wire interface provide temperature readings that indicate the device temperature. No additional components are required; the devices are truly temperature-to-digital converters. Temperature readings are communicated from the device over an SPI interface or a 3-wire serial interface. The choice of interface is selectable by the user. For applications that require greater temperature resolution, the user can adjust the readout resolution from 9 to 12 bits. This is particularly useful in applications where thermal runaway conditions must be detected quickly. The thermostat has a dedicated open-drain output (active-low TOUT). Two thermostat operating modes, comparator and interrupt, control thermostat operation based on user-defined nonvolatile trip points (THIGH and TLOW). Both devices feature a 1.7V to 3.7V supply rail.ApplicationsAny Thermally Sensitive SystemsCellular Base StationsIndustrial EquipmentNetworking Equipment

The MAX31875 is a ±1°C-accurate local temperature sensor with I2C/SMBus interface. The combination of tinypackage and excellent temperature measurement accuracymakes this product ideal for a variety of equipment.The I2C/SMBus-compatible serial interface accepts standard write byte, read byte, send byte, and receive byte commands to read the temperature data and configure the behavior of the sensor. Bus timeout resets the interface if the clock is low for more than 30ms (nominal). PEC helps to avoid communication errors when used with a master that supports this feature.The MAX31875 is available in a 4-bump, wafer-level package (WLP) and operates over the -50°C to +150°C temperature range. Design Solution: Cool Down with a Smaller, Lower Power Temperature Sensor ›ApplicationsBattery-Powered EquipmentData Communications EquipmentHandheld ElectronicsIndustrial EquipmentServers

The MAX1668/MAX1805/MAX1989 are precise multichannel digital thermometers that report the temperature of all remote sensors and their own packages. The remote sensors are diode-connected transistors—typically low-cost, easily mounted 2N3904 NPN types—that replace conventional thermistors or thermocouples. Remote accuracy is ±3°C for multiple transistor manufacturers, with no calibration needed. The remote channels 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 format 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.ApplicationsCentral Office Telecom EquipmentDesktop/Notebook ComputersIndustrial ControlsLAN ServersMultichip ModulesTest and Measurement Equipment