MAX6646/MAX6647/MAX6649 19-2540 Rev 4 7/12 +145C Precision SMBus-Compatible Remote/ Local Sensors with Overtemperature Alarms General Description Features The MAX6646/MAX6647/MAX6649 are precise, two- Dual Channel: Measures Remote and Local channel digital temperature sensors. The devices accu- Temperature rately measure the temperature of their own die and a 0.125C Resolution remote PN junction, and report the temperature in digital form using a 2-wire serial interface. The remote PN junc- High Accuracy 1C (max) from +60C to +145C tion is typically the emitter-base junction of a common- (Remote), and 2C (max) from +60C to +100C collector PNP on a CPU, FPGA, or ASIC. (Local) The 2-wire serial interface accepts standard system man- Measures High-Ideality Thermal Diodes Up to agement bus (SMBus) write byte, read byte, send byte, +170C (Apparent) and receive byte commands to read the temperature +145C (Real) data and to program the alarm thresholds. To enhance system reliability, the MAX6646/MAX6647/MAX6649 Two Alarm Outputs: ALERT and OVERT include an SMBus timeout. A fault queue prevents the Programmable Under/Overtemperature Alarm ALERT and OVERT outputs from setting until a fault has been detected one, two, or three consecutive times Temperature Thresholds (programmable). Programmable Conversion Rate The MAX6646/MAX6647/MAX6649 provide two system SMBus-Compatible Interface alarms: ALERT and OVERT. ALERT asserts when any of four temperature conditions are violated: local overtem- SMBus Timeout perature, remote overtemperature, local undertempera- ture, or remote undertemperature. OVERT asserts when Ordering Information the temperature rises above the value in either of the two OVERT limit registers. The OVERT output can be used to TEMP PIN- MEASURED PART activate a cooling fan, or to trigger a system shutdown. RANGE PACKAGE TEMP RANGE Measurements can be done autonomously, at the pro- -55C to MAX6646MUA+ 8 MAX 0C to +145C grammed conversion rate, or in a single-shot mode. The +125C adjustable conversion rate allows optimizing supply cur- -55C to rent and temperature update rate to match system needs. MAX6647MUA+ 8 MAX 0C to +145C +125C Remote accuracy is 1C maximum error between +60C -55C to and +145C with no calibration needed. The MAX6646/ MAX6649MUA+ 8 MAX 0C to +145C +125C MAX6647/MAX6649 operate from -55C to +125C, and measure temperatures between 0C and +145C. The +Denotes a lead(Pb)-free/RoHS-compliant package. MAX6646/MAX6647/MAX6649 are available in an 8-pin MAX package. Typical Operating Circuit Applications 3.3V Graphics Processors Thin Clients 0.1F 200 Desktop Computers Workstations V CC 10k EACH Notebook Computers Test and Measurement MAX6646 Servers Multichip Modules DXP SDA DATA MAX6647 MAX6649 CLOCK SCLK Selector Guide, Pin Configurations, and Functional Diagram ALERT INTERRUPT TO P DXN appear at end of data sheet. 2200pF OVERT TO FAN DRIVER OR GND SYSTEM SHUTDOWN P MAX is a registered trademark of Maxim Integrated Products, Inc. For pricing, delivery, and ordering information, please contact Maxim Direct 1 at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.+145C Precision SMBus-Compatible Remote/ Local Sensors with Overtemperature Alarms ABSOLUTE MAXIMUM RATINGS All Voltages Referenced to GND ESD Protection (all pins, Human Body Model)................2000V V ...........................................................................-0.3V to +6V Junction Temperature......................................................+150C CC DXP.............................................................-0.3V to (V + 0.3V) Operating Temperature Range .........................-55C to +125C CC DXN .......................................................................-0.3V to +0.8V Storage Temperature Range .............................-65C to +150C SCLK, SDA, ALERT, OVERT.....................................-0.3V to +6V Soldering Temperature (reflow) .......................................+260C SDA, ALERT, OVERT Current .............................-1mA to +50mA Lead Temperature (soldering, 10s) .................................+300C DXN Current .......................................................................1mA Continuous Power Dissipation (T = +70C) A MAX (derate 4.8mW/C above +70C) ...................387.8mW 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 (V = 3.0V to 5.5V, T = -55C to +125C, unless otherwise specified. Typical values are at V = 3.3V and T = +100C.) (Note 1) CC A CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage V 3.0 5.5 V CC 0.125 C Temperature Resolution 11 Bits V = 3.3V, T = +100C, CC A -1.0 +1.0 T = +60C to +145C RJ V = 3.3V, T = +60C to +100C, CC A Remote Temperature Error -1.6 +1.6 C T = +25C to +145C RJ V = 3.3V, T = +0C to +100C, CC A -3.2 +3.2 T = +0C to +145C RJ T = +60C to +100C -2.0 +2.0 A Local Temperature Error V = 3.3V C CC T = 0C to +125C -3.0 +3.0 A Supply Sensitivity of 0.2 C/V Temperature Error Undervoltage Lockout (UVLO) UVLO Falling edge of V disables ADC 2.4 2.7 2.95 V CC Threshold UVLO Hysteresis 90 mV Power-On-Reset (POR) Threshold V falling edge 2.0 V CC POR Threshold Hysteresis 90 mV Standby Supply Current SMBus static 3 12 A Operating Current During conversion 0.08 mA 0.25 conversions per second 40 80 Average Operating Current A 2 conversions per second 250 400 Conversion Time t From stop bit to conversion completion 95 125 156 ms CONV Conversion Time Error -25 +25 % DXP and DXN Leakage Current Standby mode 100 nA High level 80 100 120 Remote-Diode Source Current I A RJ Low level 8 10 12 2 MAX6646/MAX6647/MAX6649