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

The MAX6654 is a precise digital thermometer that reports the temperature of both a remote P-N junction and its own die. The remote junction can be a diode-connected transistor—typically a low-cost, easily mounted 2N3904 NPN type or 2N3906 PNP type—that replaces conventional thermistors or thermocouples. Remote accuracy is ±1°C for multiple transistor manufacturers, with no calibration needed. The remote junction can also be a common-collector PNP, such as a substrate PNP of a microprocessor (µP).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. 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 conversion rate allows the user to optimize supply current and temperature update rate to match system needs. When the conversion rate is faster than 1Hz, the conversion results are available as a 7-bit-plus-sign byte with a 1°C LSB. When the conversion rate is 1Hz or slower, the MAX6654 enters the extended mode. In this mode, 3 additional bits of temperature data are available in the extended resolution register, providing 10-bit-plus-sign resolution with a 0.125°C LSB. Singleshot conversions also have 0.125°C per LSB resolution when the conversion rate is 1Hz or slower.A parasitic resistance cancellation (PRC) mode can also be invoked for conversion rates of 1Hz or slower by setting bit 4 of the configuration register to 1. In PRC mode, the effect of series resistance on the leads of the external diode is canceled. The 11-bit conversion in PRC mode is performed in The MAX6654 default low-temperature measurement limit is 0°C. This can be extended to -64°C by setting bit 5 of the configuration register to 1.The MAX6654 is available in a small, 16-pin QSOP surface-mount package.ApplicationsComputers: Desktop, Workstation, ServerMultichip ModulesNotebook ComputersServersTest and Measurement EquipmentThin ClientsWorkstations

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 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

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

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

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 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 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