The DS1721 digital thermometer and thermostat features ±1°C accuracy over a -10°C to +85°C range. Thermometer data is read out over a 2-wire serial bus in 2's complement format with 9 to 12 bits of resolution (user-programmable). The DS1721 features three address inputs, allowing users to multidrop up to eight DS1721 devices on one bus.The DS1721 offers thermostatic functionality with over-temperature (TH) and under-temperature (TL) user-programmable trip-points stored in on-chip SRAM. The two trip-points provide programmable thermostat hysteresis: the thermostat output is asserted when the measured temperature exceeds TH and it remains active until the temperature falls below TL. The DS1721 is available in 150mil 8-pin SO (DS1721S) and 8-pin µMAX/µSOP (DS1721U) packages. For applications requiring higher precision, the DS1631 provides ±0.5°C accuracy and is functionally compatible with the DS1721.ApplicationsAlarm SystemsFibre ChannelInstrumentationNetworking

Multi-Sensor High Accuracy Digital Temperature Measurement System with EEPROM Features:Directly Digitizes 2-, 3-, or 4-Wire RTDs, Thermocouples, Thermistors, and DiodesOn-Chip EEPROM (LTC2986-1) Stores Channel Configuration Data and Custom CoefficientsSingle 2.85V to 5.25V Supply10 Flexible Inputs Allow Interchanging SensorsAutomatic Thermocouple Cold Junction CompensationBuilt-In Standard and User-Programmable Coefficients for Thermocouples, RTDs and ThermistorsMeasures Negative Thermocouple VoltagesAutomatic Burn Out, Short-Circuit and Fault DetectionBuffered Inputs Allow External ProtectionSimultaneous 50Hz/60Hz RejectionIncludes 15ppm/°C (Max) ReferenceIncludes Special Protection Modes

HUMIDITY/TEMP SENSOR, -40 TO 125DEG C; Humidity Range:0% to 100% Relative Humidity; Humidity Accuracy:± 2% RH; Temperature Accuracy:± 0.2°C; RH Response Time:4s; Temperature Response Time:2s; Sensor Interface Type:I2C RoHS Compliant: Yes

TEMPERATURE SENSOR

Thermostats Open on Rise,15A/10A Manual Reset

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 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