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 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 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 MAX6639 monitors its own temperature and one external diode-connected transistor or the temperatures of two external diode-connected transistors, typically available in CPUs, FPGAs, or GPUs. 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 program the alarm thresholds. Temperature data can be read at any time over the SMBus, and three programmable alarm outputs can be used to generate interrupts, throttle signals, or overtemperature shutdown signals.The temperature data is also used by the internal dual-PWM fan-speed controller to adjust the speed of up to two cooling fans, thereby minimizing noise when the system is running cool, but providing maximum cooling when power dissipation increases. Speed control is accomplished by tachometer feedback from the fan, so that the speed of the fan is controlled, not just the PWM duty cycle. Accuracy of speed measurement is ±4%.The MAX6639 is available in 16-pin QSOP and 16-pin thin QFN 5mm x 5mm packages. It operates from 3.0V to 3.6V and consumes just 500µA of supply current.ApplicationsDesktop ComputersNetworking EquipmentNotebook ComputersProjectorsServers

The MAX7500–MAX7504 temperature sensors accurately measure temperature and provide an overtemperature alarm/interrupt/shutdown output. These devices convert the temperature measurements to digital form using a high-resolution, sigma-delta, analog-to-digital converter (ADC). Communication is through an I²C-compatible 2-wire serial interface. The MAX7500/MAX7501/MAX7502 integrate a timeout feature that offers protection against I²C bus lockups. The MAX7503/MAX7504 do not include the timeout feature.The 2-wire 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 open-drain overtemperature shutdown output.The MAX7500 features three address select lines, while the MAX7501–MAX7504 feature two address select lines and an active-low RESET input. The MAX7500/MAX7501/MAX7502s' 3.0V to 5.5V supply voltage range, low250µA supply current, and a lockup-protected I²C-compatible interface make them ideal for a wide range of applications, including personal computers (PCs), electronic test equipment, and office electronics.The MAX7500–MAX7504 are available in 8-pin µMAX® and SO packages and operate over the -55°C to +125°C temperature range.ApplicationsElectronic Test EquipmentIndustrial Process ControlOffice ElectronicsPCsServers

The MAX7500–MAX7504 temperature sensors accurately measure temperature and provide an overtemperature alarm/interrupt/shutdown output. These devices convert the temperature measurements to digital form using a high-resolution, sigma-delta, analog-to-digital converter (ADC). Communication is through an I²C-compatible 2-wire serial interface. The MAX7500/MAX7501/MAX7502 integrate a timeout feature that offers protection against I²C bus lockups. The MAX7503/MAX7504 do not include the timeout feature.The 2-wire 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 open-drain overtemperature shutdown output.The MAX7500 features three address select lines, while the MAX7501–MAX7504 feature two address select lines and an active-low RESET input. The MAX7500/MAX7501/MAX7502s' 3.0V to 5.5V supply voltage range, low250µA supply current, and a lockup-protected I²C-compatible interface make them ideal for a wide range of applications, including personal computers (PCs), electronic test equipment, and office electronics.The MAX7500–MAX7504 are available in 8-pin µMAX® and SO packages and operate over the -55°C to +125°C temperature range.ApplicationsElectronic Test EquipmentIndustrial Process ControlOffice ElectronicsPCsServers

The MAX1619 is a precise digital thermometer that reports the temperature of both a remote sensor and its own package. The remote sensor is a diode-connected transistor-typically a low-cost, easily mounted 2N3904 NPN type-that replaces conventional thermistors or thermocouples. Remote accuracy is ±3°C for multiple transistor manufacturers, with no calibration needed. The remote channel 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. Measurements can be done automatically and autonomously, with the conversion rate programmed by the user or programmed to operate in a single-shot mode. The adjustable rate allows the user to control the supply-current drain.The MAX1619 is nearly identical to the popular MAX1617A, with the additional feature of an overtemperature alarm output (active-low OVERT) that responds to the remote temperature; this is optimal for fan control.ApplicationsCentral Office Telecom EquipmentComputers: Desktop, Workstation, ServerIndustrial ControlsLAN ServersMultichip ModulesSmart Battery Packs/ChargersTest and Measurement Equipment

The LTK001 is a thermocouple amplifier supplied with a matched cold junction compensator. By separating the amplifier and compensator functions, the problem of compensator temperature rise is virtually eliminated. The compensator is a selected version of the LT1025 cold junction compensator. The amplifier, which is also available separately as LTKA0x has been specially selected for thermocouple applications. It has low supply current to minimize warmup drift, very low offset voltage (<35µV), high gain, and extremely low input bias currents (<600pA) to allow high impedance input filters to be used without degrading offset voltage or drift.Matching of the kits is accomplished by separating the compensators and amplifiers according to the polarity of their initial (room temperature) errors. This eliminates the need to sum the errors of the two components to find the worst-case error.The LTK001 has direct thermocouple outputs of 60.9µV/°C (E), 51.7µV/°C (J), 40.6µV/°C (K, T), and 5.95µV/°C (R, S). It also has a 10mV/°C output which can be scaled to match any arbitrary thermocouple.For multiple thermocouple applications using one compensator, amplifiers may be ordered separately (LTKA0x), still matched to the compensator.Applications Thermocouple Cold Junction Compensation

The MAX6501–MAX6504 low-cost, fully integrated temperature switches assert a logic signal when their die temperature crosses a factory-programmed threshold. Operating from a +2.7V to +5.5V supply, these devices feature two on-chip, temperature-dependent voltage references and a comparator. They are available with factory-trimmed temperature trip thresholds from -45°C to +125°C in 10°C increments, and are accurate to ±0.5°C (typ) or ±6°C (max). These devices require no external components and typically consume 30µA supply current. Hysteresis is pin-selectable at 2°C or 10°C.The MAX6501/MAX6503 have an active-low, open-drain output intended to interface with a microprocessor (µP) reset input. The MAX6502/MAX6504 have an active-high, push-pull output intended to directly drive fan-control logic. The MAX6501/MAX6502 are offered with hot-temperature thresholds (+35°C to +125°C), asserting when the temperature is above the threshold. The MAX6503/MAX6504 are offered with cold-temperature thresholds (-45°C to +15°C), asserting when the temperature is below the threshold.The MAX6501–MAX6504 are offered in eight standard temperature versions; contact the factory for pricing and availability of nonstandard temperature versions. They are available in 5-pin SOT23 package.ApplicationsµP Temperature Monitoring in High-Speed ComputersFan ControlTemperature AlarmsTemperature Control

The LM75 temperature sensor includes a delta-sigma analog-to-digital converter, and a digital overtemperature detector. The host can query the LM75 through itsI²C interface to read temperature at any time. The open-drain overtemperature output (OS) sinks current when the programmable temperature limit is exceeded. The OS output operates in either of two modes, comparatoror interrupt. The host controls the temperature at which the alarm is asserted (TOS) and the hysteresis temperature below which the alarm condition is not valid (THYST). Also, the LM75's TOS and THYST registers can be read by the host. The address of the LM75 is set with three pins to allow multiple devices to work on the same bus. Power-up is in comparator mode, with defaults of TOS = +80°C and THYST = +75°C. The 3.0V to 5.5V supply voltage range, low supply current, and I²C interface make the LM75 ideal for many applications in thermal management and protection.ApplicationsComputers and Office ElectronicsTest EquipmentThermal ProtectionThermal System Management