MAX6680/MAX6681 19-2305 Rev 1 1/05 1C Fail-Safe Remote/Local Temperature Sensors with SMBus Interface General Description Features The MAX6680/MAX6681 are precise, two-channel digi- Two Alarm Outputs: ALERT and OVERT tal thermometers. Each accurately measures the tem- Pin-Programmable Threshold for OVERT Limit perature of its own die and one remote PN junction and reports the temperature on a 2-wire serial interface. The Programmable Under/Overtemperature ALERT remote junction can be a diode-connected transistor Limit like the low-cost NPN type 2N3904 or PNP type 2N3906. The remote junction can also be a common- Dual Channel: Measures Remote and Local collector PNP, such as a substrate PNP of a micro- Temperature processor. 11-Bit, 0.125C Resolution for Remote Temperature The MAX6680/MAX6681 include pin-programmable Measurements default temperature thresholds for the OVERT output, High Accuracy 1C (max) from +60C to +100C which provides fail-safe clock throttling or system shut- down. In addition, the devices are pin programmable to (Remote) select whether the OVERT output responds to either the No Calibration Required local, remote, or both temperatures. 2 SMBus/I C-Compatible Interface The 2-wire serial interface accepts standard System Management Bus (SMBus) commands such as Write SMBus Timeout Prevents SMBus Lockup 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 func- tion autonomously with a programmable conversion rate, which allows the control of supply current and Ordering Information temperature update rate to match system needs. For PART TEMP RANGE PIN-PACKAGE conversion rates of 4Hz or less, the remote sensor tem- perature can be represented in extended mode as 10 MAX6680MEE -55C to +125C 16 QSOP bits + sign with a resolution of 0.125C. When the con- MAX6681MEE -55C to +125C 16 QSOP version rate is 8Hz, output data is 7 bits + sign with a resolution of 1C. The MAX6680/MAX6681 also include an SMBus timeout feature to enhance system reliability. The MAX6681 is an upgrade to the MAX6654. The Typical Operating Circuit MAX6680/MAX6681 remote accuracy is 1C with no calibration needed. They are available in a 16-pin QSOP package and operate throughout the -55C to +125C temperature range. 3.3V 0.1F 200 Applications 10k Desktop Computers EACH Notebook V CC STBY DXP Computers SMBDATA DATA SMBCLK DXN CLOCK Servers 2200pF ALERT INTERRUPT MAX6680 Thin Clients TO P MAX6681 Workstations SENS SEL RESET MICROPROCESSOR INT SEL OVERT TO SYSTEM ADD0 SHUTDOWN Pin Configurations appear at end of data sheet. ADD1 GND CRIT0 CRIT1 SMBus is a trademark of Intel Corp. 2 I C is a trademark of Philips Corp. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.1C Fail-Safe Remote/Local Temperature Sensors with SMBus Interface ABSOLUTE MAXIMUM RATINGS V ...........................................................................-0.3V to +6V Continuous Power Dissipation (T = +70C) CC A DXP.............................................................-0.3V to (V + 0.3V) 16-Pin QSOP (derate 8.3mW/C above +70C) ..........664mW CC DXN ......................................................................-0.3V to +0.8V Junction Temperature .....................................................+150C SMBCLK, SMBDATA, ALERT, OVERT .....................-0.3V to +6V Storage Temperature Range ............................-65C to +150C RESET, INT SEL, STBY, ADD0, ADD1.....................-0.3V to +6V Lead Temperature (soldering, 10s) ................................+300C CRIT1, CRIT0, SENS SEL ........................................-0.3V to +6V SMBDATA, ALERT, OVERT, Current ..................-1mA to +50mA DXN Current ......................................................................1mA Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (Circuit of Typical Operating Circuit, V = 3.0V to 5.5V, T = -25C to +125C, unless otherwise specified. Typical values are at V CC A CC = 3.3V and T = +25C.) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 1C Temperature Resolution, Legacy Mode 8 Bits 0.125 C Temperature Resolution, Extended Mode 11 Bits T = +60C to +100C, V = 3.3V -1.0 +1.0 RJ CC Remote Te mp erat ure E r r or ( N ote 1) T = +50C to +120C, V = 3.3V -2.0 +2.0 C RJ CC T = -55C to +125C, V = 3.3V -3.0 +3.0 RJ CC T = +60C to +100C, V = 3.3V -1.5 +1.5 A CC Local Temperature Error T = 0C to +125C, V = 3.3V -3.0 +3.0 C A CC T = -55C to +125C, V = 3.3V (Note 2) -5.0 +5.0 A CC Line Regulation 3.0V V 5.5V 0.2 0.6 mC/V CC Supply Voltage Range V 3.0 5.5 V CC Undervoltage Lockout Threshold UVLO Falling edge of V disables ADC 2.60 2.80 2.95 V CC mV Undervoltage Lockout Hysteresis 90 Power-On Reset (POR) V , falling edge 1.5 2.0 2.5 V CC Threshold POR Threshold Hysteresis 90 mV Legacy 62.5 Conversion Time ms Extended 125 Standby Supply Current SMBus static 3 10 A Operating Current During conversion 0.55 1.0 mA 0.25 conversions/s 35 70 Average Operating Current A (Note 3) 2 conversions/s 120 180 DXP and DXN Leakage Current In standby mode 2 A High level 80 100 120 Remote-Diode Source Current I A RJ Low level 8 10 12 2 MAX6680/MAX6681