This low-voltage (1.7V to 3.7V) digital thermometerand thermostat provides 9, 10, 11, or 12-bit digitaltemperature readings over a -55°C to +125°C rangewith ±2°C accuracy over a -25°C to +100°C range. Atpower-up, the DS75LX defaults to 9-bit resolution forsoftware compatibility with the LM75. Communicationwith the DS75LX is achieved through a simple 2-wireserial interface. Three tri-state address pins allow upto 27 DS75LX devices to operate on the same 2-wirebus, which greatly simplifies distributed temperature-sensingapplications.The DS75LX thermostat has a dedicated open-drainoutput (O.S.) and programmable fault tolerance,which allow the user to define the number ofconsecutive error conditions that must occur beforeO.S. is activated. There are two thermostaticoperating modes that control thermostat operationbased on user-defined trip-points (TOS and THYST).ApplicationsAny Thermally Sensitive SystemCellular Base StationsServersTelecom Switches and Routers

The MAX6509/MAX6510 are fully integrated, resistor-programmable temperature switches with thresholds set by an external resistor. They require only one external resistor to set the temperature threshold within a wide -40±C to +125±C temperature range. The MAX6509 provides an open-drain output. The MAX6510 features three selectable output options: active-low, active-high, and open drain with an internal pull-up resistor.These switches operate with a +2.7V to +5.5V single supply while providing a temperature threshold accuracy of ±0.5°C (typ) or ±4.7°C (max). They typically consume 32µA supply current. Hysteresis is pin selectable to 2°C or 10°C.The MAX6509/MAX6510 are available in 5-pin and 6-pin SOT23 packages, respectively.ApplicationsµP Temperature Monitoring in High-Speed ComputersFan ControlTemperature AlarmsTemperature Control

The MAX1298/MAX1299 implement local and remote temperature sensing with 12-bit resolution, using +5V and +3V supply voltages, respectively. Accuracy is ±1°C from 0 to +70°C, with no calibration needed. The devices feature an algorithmic switched-capacitor analog-to-digital converter (ADC), an on-chip clock, and a 3-wire serial interface compatible with SPI, QSPI™, and MICROWIRE®.The MAX1298/MAX1299 also perform fully differential voltage measurements with 12-bit resolution and separate track-and-hold (T/H) for positive and negative inputs. Both devices accept versatile input modes consisting of two 3-channel signal pairs, five 1-channel signals relative to an AIN5, or VDD/4 relative to ground. An external reference may be used for more accurate voltage measurements.Typical power consumption is only 1.3mW (MAX1299). A shutdown mode and two standby modes provide multiple strategies for prolonging battery life in portable applications that require limited sampling throughput.The MAX1298/MAX1299 are available in 16-pin SSOP packages.ApplicationsHandheld Instruments (PDAs, Palmtops)Industrial Process ControlsMedical Equipment

The MAX6629–MAX6632 are local digital temperature sensors with an SPI-compatible serial interface. The temperature is converted to a 12-bit + sign word with a resolution of 0.0625°C/LSB. An extended temperature range provides useful readings up to +150°C.These sensors are 3-wire serial interface SPI compatible, allowing the MAX6629–MAX6632 to be readily connected to a variety of microcontrollers (µCs). The MAX6629–MAX6632 are read-only devices, simplifying their use in systems where only temperature data is required.All four digital temperature sensors require very little supply current, making them ideal for portable systems. The MAX6631/MAX6632 perform a temperature-to-digital conversion once every 8s and require minimal average supply current, 32µA (typ). The MAX6629/MAX6630 perform a conversion once every 0.5s and require only 200µA (typ) supply current. Any of these temperature sensors can perform conversions more often—up to approximately four conversions per second by reading the conversion results more often.ApplicationsCellularHard Disk DriveHVACsIndustrial ControlSystems

The MAX6680/MAX6681 are precise, two-channel digital thermometers. Each accurately measures the temperature of its own die and one remote PN junction and reports the temperature on a 2-wire serial interface. The remote junction can be a diode-connected transistor like the low-cost NPN type 2N3904 or PNP type 2N3906. The remote junction can also be a common-collector PNP, such as a substrate PNP of a microprocessor.The MAX6680/MAX6681 include pin-programmable default temperature thresholds for the active-low OVERT output, which provides fail-safe clock throttling or system shutdown. In addition, the devices are pin programmable to select whether the active-low OVERT output responds to either the local, remote, or both temperatures.The 2-wire serial interface accepts standard System Management Bus (SMBus™) commands such as Write Byte, Read Byte, Send Byte, and Receive Byte to read the temperature data and program the alarm thresholds and conversion rate. The MAX6680/MAX6681 can function autonomously with a programmable conversion rate, which allows the control of supply current and temperature update rate to match system needs. For conversion rates of 4Hz or less, the remote sensor temperature can be represented in extended mode as 10 bits + sign with a resolution of 0.125°C. When the conversion rate is 8Hz, output data is 7 bits + sign with a resolution of 1°C. The MAX6680/MAX6681 also include an SMBus timeout feature to enhance system reliability.The MAX6681 is an upgrade to the MAX6654. The MAX6680/MAX6681 remote accuracy is ±1°C with no calibration needed. They are available in a 16-pin QSOP package and operate throughout the -55°C to +125°C temperature range.ApplicationsDesktop ComputersNotebook ComputersServersThin ClientsWorkstations

MAX6685/MAX6686 are dual-output temperature switches that use an external diode-connected transistor as a sensing element. These devices have two logic outputs (THIGH and TLOW). THIGH asserts a logic signal when the remote temperature crosses the factory-programmed, +120°C, or +125°C upper trip threshold. TLOW is asserted when the remote temperature exceeds the lower threshold, which is controlled by pins S1 and S2. The lower thresholds are available in two ranges in 5°C increments. The two ranges are +40°C to +80°C and +75°C to +115°C. Hysteresis for both outputs to be deasserted is typically 5°C.THIGH is an open-drain, active-low output for both the MAX6685 and the MAX6686. TLOW is a CMOS push-pull, active-high output for the MAX6685 and is an open-drain, active-low output for the MAX6686. They are available in a space-saving 8-pin µMAX package.ApplicationsCPU Temperature ProtectionFan ControlFPGA Temperature ProtectionMultichip Modules

Thermostats High-Precision Digital Thermometer and Thermostat

The DS1631, DS1631A, and DS1731 digital thermometers provide 9, 10, 11, or 12-bit temperature readings over a -55°C to +125°C range. The DS1631 and DS1631A thermometer accuracy is ±0.5°C from 0°C to +70°C with 3.0V ≤ VDD ≤ 5.5V, and the DS1731 accuracy is ±1°C from -10°C to +85°C with 3.0V ≤ VDD ≤ 5.5V. The thermostat on all three devices provides custom hysteresis with user-defined trip points (TH and TL). The TH and TL 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.ApplicationsMedicalNetworkingPersonal ComputingRouters/SwitchesTest Measurement SystemsWireless Base Stations

The DS1775 digital thermometer and thermostatprovides temperature readings that indicate the device’stemperature. Thermostat settings and temperaturereadings are all communicated to/from the DS1775 overa simple 2-wire serial interface. No additional componentsare required; the device is truly a “temperature-to-digital”converter.For applications that require greater temperature resolution,the user can adjust the readout resolution from 9 to 12bits. This is particularly useful in applications wherethermal runaway conditions must be detected quickly.The open-drain thermal alarm output, O.S., becomesactive when the temperature of the device exceeds auser-defined temperature TOS. The number of consecutivefaults required to set O.S. active is configurable by theuser. The device can also be configured in the interrupt orcomparator mode, to customize the method which clearsthe fault condition.As a digital thermometer, the DS1775 is software compatiblewith the DS75 2-wire thermal watchdog. The DS1775 isassembled in a compact 5-pin SOT23 package, allowingfor low-cost thermal monitoring/control in spaceconstrainedapplications. The low thermal mass allows fortime constants previously only possible with thermistors.ApplicationsAny Thermally-Sensitive SystemCell PhonesOffice EquipmentPersonal Computers/Servers/Workstations

The DS1775 digital thermometer and thermostatprovides temperature readings that indicate the device’stemperature. Thermostat settings and temperaturereadings are all communicated to/from the DS1775 overa simple 2-wire serial interface. No additional componentsare required; the device is truly a “temperature-to-digital”converter.For applications that require greater temperature resolution,the user can adjust the readout resolution from 9 to 12bits. This is particularly useful in applications wherethermal runaway conditions must be detected quickly.The open-drain thermal alarm output, O.S., becomesactive when the temperature of the device exceeds auser-defined temperature TOS. The number of consecutivefaults required to set O.S. active is configurable by theuser. The device can also be configured in the interrupt orcomparator mode, to customize the method which clearsthe fault condition.As a digital thermometer, the DS1775 is software compatiblewith the DS75 2-wire thermal watchdog. The DS1775 isassembled in a compact 5-pin SOT23 package, allowingfor low-cost thermal monitoring/control in spaceconstrainedapplications. The low thermal mass allows fortime constants previously only possible with thermistors.ApplicationsAny Thermally-Sensitive SystemCell PhonesOffice EquipmentPersonal Computers/Servers/Workstations