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MAX6646：+145°C Precision SMBus-Compatible Remote/Local Sensors with Overtemperature Alarms

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-pin µMAX® package.

Key Features Dual Channel: Measures Remote and Local Temperature 0.125°C Resolution High Accuracy ±1°C (max) from +60°C to +145°C (Remote), and ±2°C (max) from +60°C to +100°C (Local) Measures High-Ideality Thermal Diodes Up to +170°C (Apparent) +145°C (Real) Two Alarm Outputs: Active-Low ALERT and Active-Low OVERT Programmable Under/Overtemperature Alarm Temperature Thresholds Programmable Conversion Rate SMBus-Compatible Interface SMBus Timeout

MAX6646, MAX6647, MAX6649: Typical Operating Circuit Applications/Uses Desktop Computers Graphics Processors Multichip Modules Notebook Computers Servers Test and Measurement Equipment Thin Clients Workstations

DataSheet

Parametrics

Quality and Environmental Data

• MAX6646.pdf

Related Products

• MAX6648：Precision SMBus-Compatible Remote/Local Temperature Sensors with Overtemperature Alarms
• MAX6692：Precision SMBus-Compatible Remote/Local Temperature Sensors with Overtemperature Alarms

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