±1°C Fail-Safe Remote/Local Temperature Sensors with SMBus Interface

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Part Details
Part Models 2
1ku List Price Starting From $4.98
  • Two Alarm Outputs: Active-Low ALERT and Active-Low OVERT
  • Pin-Programmable Threshold for Active-Low OVERT Limit
  • Programmable Under/Overtemperature Active-Low ALERT Limit
  • Dual Channel: Measures Remote and Local Temperature
  • 11-Bit, 0.125°C Resolution for Remote Temperature Measurements
  • High Accuracy ±1°C (max) from +60°C to +100°C (Remote)
  • No Calibration Required
  • SMBus/I²C-Compatible Interface
  • SMBus Timeout Prevents SMBus Lockup
Additional Details
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The MAX6680/MAX6681 are precise, two-channel digital thermometers. Each accurately measures the temperature of its own die and one remote PN junction and reports the temperature on a 2-wire serial interface. The remote junction can be a diode-connected transistor like the low-cost NPN type 2N3904 or PNP type 2N3906. The remote junction can also be a common-collector PNP, such as a substrate PNP of a microprocessor.

The MAX6680/MAX6681 include pin-programmable default temperature thresholds for the active-low OVERT output, which provides fail-safe clock throttling or system shutdown. In addition, the devices are pin programmable to select whether the active-low OVERT output responds to either the local, remote, or both temperatures.

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 MAX6680/MAX6681 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 remote sensor temperature can be represented in extended mode as 10 bits + sign with a resolution of 0.125°C. When the conversion rate is 8Hz, output data is 7 bits + sign with a resolution of 1°C. The MAX6680/MAX6681 also include an SMBus timeout feature to enhance system reliability.

The MAX6681 is an upgrade to the MAX6654. The MAX6680/MAX6681 remote accuracy is ±1°C with no calibration needed. They are available in a 16-pin QSOP package and operate throughout the -55°C to +125°C temperature range.

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Part Models 2
1ku List Price Starting From $4.98

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Software & Part Ecosystem

Software & Part Ecosystem

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Evaluation Kit

Evaluation Kits 1


Evaluation System/Evaluation Kit for the MAX6681



Evaluation System/Evaluation Kit for the MAX6681

Evaluation System/Evaluation Kit for the MAX6681

Features and Benefits

  • Measure and Display Temperature of the MAX6681 and a Remote Sensor
  • Programmable Alarms and Configuration
  • I²C/SMBus Compatible
  • Easy-to-Use Menu-Driven Software
  • Assembled and Tested
  • Include Windows 95/98/2000-Compatible Software and Demo PC Board

Product Detail

The MAX6681 evaluation system (EV system) consists of a MAX6681 evaluation kit (EV kit) and a companion Maxim system management bus (SMBus™) interface board.

The MAX6681 EV kit is an assembled and tested PC board that demonstrates the MAX6681 temperature sensor. The MAX6681 monitors its temperature and the junction temperature of an external diode-connected transistor. It converts the temperature to 8-bit or 11-bit 2-wire serial data. (Note: 11-bit resolution is for the external sensor only.)

The MAX6681 EV kit includes the external diode-connected transistor (a 2N3906 transistor) soldered to the board, but removable. The board can then be connected through a twisted pair to a remote diode close to your system.

The Maxim SMBus interface board (MAXSMBus) allows an IBM®-compatible PC to use its parallel port to emulate an Intel® SMBus 2-wire interface. Windows® 95/98/2000-compatible software provides a user-friendly interface to exercise the features of the MAX6681. The program is menu driven and offers a graphic interface with control buttons and status display. (Note: Windows 2000 requires the installation of a driver; refer to Win2000.pdf or Win2000.txt located on the diskette.)

Order the MAX6681EVSYS for a complete IBM PC-based evaluation of the MAX6681. Order the MAX6681EVKIT if you already have an SMBus interface.

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