The MAX6642 precise, two-channel digital temperature sensor accurately measures the temperature of its own die and a remote PN junction and reports the temperature data over a 2-wire serial interface. The remote PN junction is typically a substrate PNP transistor on the die of a CPU, ASIC, GPU, or FPGA. The remote PN junction can also be a discrete diode-connected small-signal transistor.The 2-wire serial interface accepts standard system management bus (SMBus™), Write Byte, Read Byte, Send Byte, and Receive Byte commands to read the temperature data and to program the alarm thresholds. To enhance system reliability, the MAX6642 includes an SMBus timeout. The temperature data format is 10 bits with the least significant bit (LSB) corresponding to +0.25°C. The active-low ALERT output asserts when the local or remote overtemperature thresholds are violated. A fault queue can be used to prevent the active-low ALERT output from setting until two consecutive faults have been detected.Measurements can be done autonomously or in a single-shot mode.Remote accuracy is ±1°C maximum error between +60°C and +100°C. The MAX6642 operates from -40°C to +125°C, and measures remote temperatures between 0°C and +150°C. The MAX6642 is available in a 6-pin TDFN package with an exposed pad.ApplicationsDesktop ComputersGraphic CardsNotebook ComputersServersTest and Measurement EquipmentThin ClientsWorkstations

The MAX6627/MAX6628 precise digital temperature sensors report the temperature of a remote sensor. The remote sensor is a diode-connected transistor, typically a low-cost, easily mounted 2N3904 NPN type that replaces conventional thermistors or thermocouples. The MAX6627/MAX6628 can also measure the die temperature of other ICs, such as microprocessors (µPs) or microcontrollers (µCs) that contain an on-chip, diode-connected transistor.Remote accuracy is ±1°C when the temperature of the remote diode is between 0°C and +125°C and the temperature of the MAX6627/MAX6628 is +30°C. The temperature is converted to a 12-bit + sign word with 0.0625°C resolution. The architecture of the device is capable of interpreting data as high as +145°C from the remote sensor. The MAX6627/MAX6628 temperature should never exceed +125°C.These sensors are 3-wire serial interface SPI-compatible, allowing the MAX6627/MAX6628 to be readily connected to a variety of µCs. The MAX6627/MAX6628 are read-only devices, simplifying their use in systems where only temperature data is required.Two conversion rates are available, one that continuously converts data every 0.5s (MAX6627), and one that converts data every 8s (MAX6628). The slower version provides minimal power consumption under all operating conditions (30µA, typ). Either device can be read at any time and provide the data from the last conversion.Both devices operate with supply voltages between +3.0V and +5.5V, are specified between -55°C and +125°C, and come in space-saving 8-pin SOT23 and lead-free TDFN packages.ApplicationsHard Disk DriveIndustrial Control SystemsNotebooks, PCsSmart Battery Packs/Chargers

The MAX6646/MAX6647/MAX6649 are precise, two-channel digital temperature sensors. The devices accurately measure the temperature of their own die and a remote PN junction, and report the temperature in digital form using a 2-wire serial interface. The remote PN junction is typically the emitter-base junction of a common-collector PNP on a CPU, FPGA, or ASIC.The 2-wire serial interface accepts standard system management bus (SMBus) write byte, read byte, send byte, and receive byte commands to read the temperature data and to program the alarm thresholds. To enhance system reliability, the MAX6646/MAX6647/MAX6649 include an SMBus timeout. A fault queue prevents the active-low ALERT and active-low OVERT outputs from setting until a fault has been detected one, two, or three consecutive times (programmable).The MAX6646/MAX6647/MAX6649 provide two system alarms: active-low ALERT and active-low OVERT. Active-low ALERT asserts when any of four temperature conditions are violated: local overtemperature, remote overtemperature, local undertemperature, or remote undertemperature. Active-low OVERT asserts when the temperature rises above the value in either of the two active-low OVERT limit registers. The active-low OVERT output can be used to activate a cooling fan, or to trigger a system shutdown.Measurements can be done autonomously, at the programmed conversion rate, or in a single-shot mode. The adjustable conversion rate allows optimizing supply current and temperature update rate to match system needs.Remote accuracy is ±1°C maximum error between +60°C and +145°C with no calibration needed. The MAX6646/MAX6647/MAX6649 operate from -55°C to +125°C, and measure temperatures between 0°C and +145°C. The MAX6646/MAX6647/MAX6649 are available in an 8-pinµMAX® package.ApplicationsDesktop ComputersGraphics ProcessorsMultichip ModulesNotebook ComputersServersTest and Measurement EquipmentThin ClientsWorkstations

The MAX6655/MAX6656 are precise voltage and temperature monitors. The digital thermometer reports the temperature of two remote sensors and its own die temperature. The remote sensors are diode-connected transistors—typically a low-cost, easily mounted 2N3906 PNP type—that replace conventional thermistors or thermocouples. Remote accuracy is ±1°C for multiple transistor manufacturers with no calibration necessary. The remote channels can also measure the die temperature of other ICs, such as microprocessors, that contain a substrate-connected PNP with its collector grounded and its base and emitter available for temperature-sensing purposes. The temperature is digitized with 11-bit resolution.The MAX6655/MAX6656 also measure their own supply voltage and three external voltages with 8-bit resolution. Each voltage input's sensitivity is set to give approximately 3/4-scale output code when the input voltage is at its nominal value. The MAX6655 operates at +5V supply and its second voltage monitor is 3.3V. The MAX6656 operates on a +3.3V supply and its second voltage monitor is 5V.The 2-wire serial interface accepts standard SMBus™ Write Byte, Read Byte, Send Byte, and Receive Byte commands to program the alarm thresholds and to read data. The MAX6655/MAX6656 also provide SMBus alert response and timeout functions. The MAX6655/MAX6656 measure automatically and autonomously, with the conversion rate programmable. The adjustable rate allows the user to control the supply current.In addition to the SMBus active-low ALERT output, the MAX6655/MAX6656 feature an active-low OVERT output, which is used as a temperature reset that remains active only while the temperature is above the maximum temperature limit. The active-low OVERT output is optimal for fan control or for system shutdown.ApplicationsCommunication SystemsComputers: Desktop, Workstation, ServerNotebook ComputersServersThin ClientsWorkstations

The MAX6657/MAX6658/MAX6659 are precise, two-channel digital temperature sensors. Each accurately measures the temperature of its own die and one remote PN junction, and reports the temperature in digital form on a 2-wire serial interface. The remote junction can be a diode-connected transistor like the low-cost NPN type 2N3904 or 2N3906 PNP type. The remote junction can also be a common-collector PNP, such as a substrate PNP of a microprocessor.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 MAX6657/MAX6658/MAX6659 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 temperature is represented in extended mode as 10 bits + sign with a resolution of 0.125°C. When the conversion rate is faster than 4Hz, output data is 7 bits + sign with a resolution of 1°C. The MAX6657/MAX6658/MAX6659 also include an SMBus timeout feature to enhance system reliability.Remote accuracy is ±1°C between +60°C and +100°C with no calibration needed. The MAX6657 measures temperatures from 0°C to +125°C and the MAX6658/MAX6659 from -55°C to +125°C. The MAX6659 has the added benefit of being able to select one of three addresses through an address pin, and a second over-temperature alarm pin for greater system reliability.ApplicationsComputers: Desktop, Workstation, ServerNotebook ComputersServersWorkstations

The MAX6657/MAX6658/MAX6659 are precise, two-channel digital temperature sensors. Each accurately measures the temperature of its own die and one remote PN junction, and reports the temperature in digital form on a 2-wire serial interface. The remote junction can be a diode-connected transistor like the low-cost NPN type 2N3904 or 2N3906 PNP type. The remote junction can also be a common-collector PNP, such as a substrate PNP of a microprocessor.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 MAX6657/MAX6658/MAX6659 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 temperature is represented in extended mode as 10 bits + sign with a resolution of 0.125°C. When the conversion rate is faster than 4Hz, output data is 7 bits + sign with a resolution of 1°C. The MAX6657/MAX6658/MAX6659 also include an SMBus timeout feature to enhance system reliability.Remote accuracy is ±1°C between +60°C and +100°C with no calibration needed. The MAX6657 measures temperatures from 0°C to +125°C and the MAX6658/MAX6659 from -55°C to +125°C. The MAX6659 has the added benefit of being able to select one of three addresses through an address pin, and a second over-temperature alarm pin for greater system reliability.ApplicationsComputers: Desktop, Workstation, ServerNotebook ComputersServersWorkstations

The MAX6662 is a 12-bit + sign temperature sensor combined with a programmable overtemperature alarm and a 3-wire (SPI-compatible) serial interface in a single package. It converts its die temperature into digital values using an internal analog-to-digital converter (ADC). The temperature data is stored in a temperature register as a 13-bit word, which allows 0.0625° resolution. The temperature data is readable at any time through the serial interface. The operating temperature range is -55° to +150°.The MAX6662 provides two programmable watchdog interrupt outputs. Active-Low ALERT is used for lower temperature warning functions, while active-low OT is used for higher temperature-critical functions, such as power-supply shutdown. The MAX6662 features a shutdown mode that saves power by disabling everything except the serial interface. The temperature sensor is available in an 8-pin SO package.ApplicationsHVACRefrigerationTest Equipment

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 DS1822-PAR is a digital thermometer with ±2°C accuracy over a -10°C to +85°C range and an operating temperature range of -55°C to +100°C. Data is read out over a 1-Wire® serial bus in 2's complement format with 9 to 12 bits of resolution (user-programmable).The DS1822-PAR is a parasite-power only version of the DS1822 that is ideal for use in remote-sensing applications such as temperature probes. Parasite power eliminates the need for a local power supply since power is derived directly from the 1-Wire bus. The DS1822-PAR provides mechanical simplicity over the DS1822 for parasite-power applications because no VDD connection is required—the DS1822 must have VDD connected to ground for operation in parasite-power mode.The DS1822-PAR offers thermostatic functionality with user-programmable over-temperature (TH) and under-temperature (TL) set points stored in on-chip EEPROM. Each DS1822-PAR features a unique and unchangeable 64-bit silicon serial number, which serves as the bus address for the sensor. This allows multiple DS1822-PAR devices to coexist on the same 1-Wire bus.The DS1822-PAR is offered a 3-pin TO-92 package. Also available is the high-precision DS18B20-PAR, which provides ±0.5°C accuracy and is software-compatible with the DS1822-PAR.ApplicationsRemote Sensing Applications