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 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 DS1620 Digital Thermometer and Thermostat provides 9-bit temperature readings which indicate the temperature of the device. With three thermal alarm outputs, the DS1620 can also act as a thermostat. THIGH is driven high if the DS1620's temperature is greater than or equal to a user-defined temperature TH. TLOW is driven high if the DS1620's temperature is less than or equal to a user-defined temperature TL. TCOM is driven high when the temperature exceeds TH and stays high until the temperature falls below that of TL.User-defined temperature settings are stored in nonvolatile memory, so parts can be programmed prior to insertion in a system, as well as used in standalone applications without a CPU. Temperature settings and temperature readings are all communicated to/from the DS1620 over a simple 3-wire interface.ApplicationsConsumer ProductsIndustrial SystemsThermometersThermostatic Controls

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 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 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 LTC2996 is a high accuracy temperature sensor with adjustable overtemperature and undertemperature thresholds and open drain alert outputs. It converts the temperature of an external diode sensor or its own die temperature to an analog output voltage while rejecting errors due to noise and series resistance. The measured temperature is compared against upper and lower limits set with resistive dividers. If a threshold is exceeded, the device communicates an alert by pulling low the correspondent open drain logic output.The LTC2996 gives ±1°C accurate temperature results using commonly available NPN or PNP transistors or temperature diodes built into modern digital devices. A 1.8V reference output simplifies threshold programming and can be used as an ADC reference input.The LTC2996 provides an accurate, low power solution for temperature monitoring in a compact 3mm × 3mm DFN package.Applications Temperature Monitoring and Measurement System Thermal Control Network Servers Desktop and Notebook Computers Environmental Monitoring