MAX6646MUA+TGA4

19-2540; Rev 4; 7/12 +145°C Precision SMBus-Compatible Remote/ Local Sensors with Overtemperature Alarms Features The MAX6646/MAX6647/MAX6649 are precise, twochannel 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 commoncollector PNP on a CPU, FPGA, or ASIC. ♦ Dual Channel: Measures Remote and Local Temperature 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 ALERT and 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: ALERT and OVERT. ALERT asserts when any of four temperature conditions are violated: local overtemperature, remote overtemperature, local undertemperature, or remote undertemperature. OVERT asserts when the temperature rises above the value in either of the two OVERT limit registers. The 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. ♦ Measures High-Ideality Thermal Diodes Up to +170°C (Apparent) +145°C (Real) 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. ♦ 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) ♦ Two Alarm Outputs: ALERT and OVERT ♦ Programmable Under/Overtemperature Alarm Temperature Thresholds ♦ Programmable Conversion Rate ♦ SMBus-Compatible Interface ♦ SMBus Timeout Ordering Information PART TEMP RANGE PINPACKAGE MEASURED TEMP RANGE MAX6646MUA+ -55°C to +125°C 8 μMAX 0°C to +145°C MAX6647MUA+ -55°C to +125°C 8 μMAX 0°C to +145°C MAX6649MUA+ -55°C to +125°C 8 μMAX 0°C to +145°C +Denotes a lead(Pb)-free/RoHS-compliant package. Typical Operating Circuit Applications Graphics Processors Thin Clients Desktop Computers Workstations Notebook Computers Test and Measurement Servers Multichip Modules 3.3V 0.1μF 200Ω VCC DXP Selector Guide, Pin Configurations, and Functional Diagram appear at end of data sheet. 2200pF μP 10kΩ EACH MAX6646 MAX6647 MAX6649 DXN SDA SCLK DATA CLOCK ALERT INTERRUPT TO μP OVERT TO FAN DRIVER OR SYSTEM SHUTDOWN GND μMAX is a registered trademark of Maxim Integrated Products, Inc. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX6646/MAX6647/MAX6649 General Description MAX6646/MAX6647/MAX6649 +145°C Precision SMBus-Compatible Remote/ Local Sensors with Overtemperature Alarms ABSOLUTE MAXIMUM RATINGS ESD Protection (all pins, Human Body Model) ................±2000V Junction Temperature ......................................................+150°C Operating Temperature Range .........................-55°C to +125°C Storage Temperature Range .............................-65°C to +150°C Soldering Temperature (reflow) .......................................+260°C Lead Temperature (soldering, 10s) .................................+300°C All Voltages Referenced to GND VCC ...........................................................................-0.3V to +6V DXP.............................................................-0.3V to (VCC + 0.3V) DXN .......................................................................-0.3V to +0.8V SCLK, SDA, ALERT, OVERT.....................................-0.3V to +6V SDA, ALERT, OVERT Current .............................-1mA to +50mA DXN Current .......................................................................±1mA Continuous Power Dissipation (TA = +70°C) μMAX (derate 4.8mW/°C above +70°C) ...................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 (VCC = 3.0V to 5.5V, TA = -55°C to +125°C, unless otherwise specified. Typical values are at VCC = 3.3V and TA = +100°C.) (Note 1) PARAMETER Supply Voltage SYMBOL CONDITIONS VCC MIN 3.0 Local Temperature Error +1.0 VCC = 3.3V, TA = +60°C to +100°C, TRJ = +25°C to +145°C -1.6 +1.6 VCC = 3.3V, TA = +0°C to +100°C, TRJ = +0°C to +145°C -3.2 +3.2 TA = +60°C to +100°C -2.0 +2.0 TA = 0°C to +125°C -3.0 +3.0 ±0.2 UVLO Falling edge of VCC disables ADC 2.4 UVLO Hysteresis VCC falling edge POR Threshold Hysteresis Standby Supply Current SMBus static Operating Current During conversion Average Operating Current 2.95 tCONV V 90 mV 3 250 400 125 Standby mode IRJ μA mA 2 conversions per second -25 DXP and DXN Leakage Current 12 0.08 80 95 V mV 40 From stop bit to conversion completion °C 2.0 0.25 conversions per second Conversion Time Error 2 2.7 °C °C/V 90 Power-On-Reset (POR) Threshold V Bits -1.0 VCC = 3.3V UNITS °C VCC = 3.3V, TA = +100°C, TRJ = +60°C to +145°C Supply Sensitivity of Temperature Error Remote-Diode Source Current 5.5 11 Remote Temperature Error Conversion Time MAX 0.125 Temperature Resolution Undervoltage Lockout (UVLO) Threshold TYP μA 156 ms +25 % 100 nA High level 80 100 120 Low level 8 10 12 μA +145°C Precision SMBus-Compatible Remote/ Local Sensors with Overtemperature Alarms (VCC = 3.0V to 5.5V, TA = -55°C to +125°C, unless otherwise specified. Typical values are at VCC = 3.3V and TA = +100°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS ALERT, OVERT Output Low Voltage Output High Leakage Current I SINK = 1mA 0.4 I SINK = 4mA 0.6 VOH = 5.5V 1 μA 0.8 V V SMBus-COMPATIBLE INTERFACE (SCLK AND SDA) Logic Input Low Voltage Logic Input High Voltage VIL VIH VCC = 3.0V 2.2 VCC = 5.5V 2.6 Input Leakage Current ILEAK VIN = V GND or VCC -1 Output Low-Sink Current ISINK VOL = 0.6V 6 Input Capacitance CIN V +1 μA mA 5 pF SMBus-COMPATIBLE TIMING (Note 2) Serial Clock Frequency f SCLK (Note 3) 100 kHz Bus Free Time Between STOP and START Condition tBUF 4.7 μs Repeat START Condition Setup Time t SU:STA 4.7 μs START Condition Hold Time tHD:STA 10% of SDA to 90% of SCLK 4 μs STOP Condition Setup Time t SU:STO 90% of SCLK to 90% of SDA 4 μs 4.7 μs Clock Low Period Clock High Period tLOW 10% to 10% tHIGH 90% to 90% Data Setup Time t SU:DAT Data Hold Time tHD:DAT (Note 4) 4 μs 250 ns 250 ns Receive SCLK/SDA Rise Time tR 1 μs Receive SCLK/SDA Fall Time tF 300 ns 50 ns 55 ms Pulse Width of Spike Suppressed SMBus Timeout Note 1: Note 2: Note 3: Note 4: t SP tTIMEOUT 0 SDA low period for interface reset 25 37 All parameters tested at a single temperature. Specifications over temperature are guaranteed by design. Timing specifications guaranteed by design. The serial interface resets when SCLK is low for more than tTIMEOUT. A transition must internally provide at least a hold time to bridge the undefined region (300ns max) of SCLK’s falling edge. 3 MAX6646/MAX6647/MAX6649 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VCC = 3.3V, TA = +25°C, unless otherwise noted.) 4.0 3.5 3.0 1.5 TEMPERATURE ERROR (°C) OPERATING SUPPLY CURRENT (μA) 4.5 2.0 MAX6649 toc02 400 MAX6649 toc01 300 200 100 1.0 0.5 0 -0.5 -1.0 TA = +85°C FAIRCHILD 2N3906 -1.5 2.5 -2.0 0 3.5 4.0 4.5 5.5 5.0 0.63 0.13 0.25 0.50 1.00 50 75 100 125 CONVERSION RATE (Hz) TEMPERATURE (°C) LOCAL TEMPERATURE ERROR vs. DIE TEMPERATURE TEMPERATURE ERROR vs. POWER-SUPPLY NOISE FREQUENCY LOCAL TEMPERATURE ERROR vs. COMMON-MODE NOISE FREQUENCY 5 MAX6649 toc04 LOCAL ERROR 0 -0.5 -1.0 -1.5 3 REMOTE ERROR 2 1 0 VCC = SQUARE WAVE APPLIED TO VCC WITH NO BYPASS CAPACITOR -1 -2.0 75 125 100 6 5 REMOTE ERROR 4 3 2 LOCAL ERROR 1 0 -2 0.1 1 TEMPERATURE (°C) 10 100 1k 10k 100k 1 10 TEMPERATURE ERROR vs. DXP-DXN CAPACITANCE 1 MAX6649 toc07 2.0 0 TEMPERATURE ERROR (°C) 1.5 1.0 0.5 0 -0.5 100 -1 -2 -3 -4 -1.0 1 10 100 1k FREQUENCY (Hz) 10k 100k -5 0.100 1k FREQUENCY (Hz) FREQUENCY (Hz) TEMPERATURE ERROR vs. DIFFERENTIAL-MODE NOISE FREQUENCY TEMPERATURE ERROR (°C) 7 MAX6649 toc08 50 VIN = AC-COUPLED TO DXN VIN = 100mVP-P 8 -1 -2 25 9 TEMPERATURE ERROR (°C) 4 TEMPERATURE ERROR (°C) 0.5 0 25 SUPPLY VOLTAGE (V) 1.0 4 0 2.00 4.00 MAX6649 toc05 3.0 MAX6649 toc06 STANDBY SUPPLY CURRENT (μA) 5.0 REMOTE TEMPERATURE ERROR vs. REMOTE-DIODE TEMPERATURE OPERATING SUPPLY CURRENT vs. CONVERSION RATE MAX6649 toc03 STANDBY SUPPLY CURRENT vs. SUPPLY VOLTAGE TEMPERATURE ERROR (°C) MAX6646/MAX6647/MAX6649 +145°C Precision SMBus-Compatible Remote/ Local Sensors with Overtemperature Alarms 1.000 10.000 DXP-DXN CAPACITANCE (nF) 100.000 10k 100k +145°C Precision SMBus-Compatible Remote/ Local Sensors with Overtemperature Alarms PIN NAME 1 VCC Supply Voltage Input, 3V to 5.5V. Bypass VCC to GND with a 0.1μF capacitor. A 200
series resistor is recommended but not required for additional noise filtering. 2 DXP Combined Remote-Diode Current Source and A/D Positive Input for Remote-Diode Channel. DO NOT LEAVE DXP UNCONNECTED; connect DXP to DXN if no remote diode is used. Place a 2200pF capacitor between DXP and DXN for noise filtering. 3 DXN Combined Remote-Diode Current Sink and A/D Negative Input. DXN is internally connected to ground. 4 OVERT Overtemperature Alert/Interrupt Output, Open Drain. OVERT is logic low when the temperature is above the software-programmed threshold. 5 GND 6 ALERT FUNCTION Ground SMBus Alert (Interrupt) Output, Open Drain. ALERT asserts when temperature exceeds limits (high or low temperature). ALERT stays asserted until acknowledged by either reading the status register or by successfully responding to an alert response address, provided that the fault condition no longer exists. See the ALERT Interrupts section. 7 SDA SMBus Serial-Data Input/Output, Open Drain 8 SCLK SMBus Serial-Clock Input Detailed Description The MAX6646/MAX6647/MAX6649 are temperature sensors designed to work in conjunction with a microprocessor or other intelligence in thermostatic, process-control, or monitoring applications. Communication with the MAX6646/MAX6647/MAX6649 occurs through the SMBus-compatible serial interface and dedicated alert and overtemperature outputs. ALERT asserts if the measured local or remote temperature is greater than the software-programmed ALERT high limit or less than the ALERT low limit in the MAX6649. ALERT also asserts, in the MAX6649, if the remote-sensing diode pins are shorted or unconnected. The overtemperature alarm, OVERT, asserts if the software-programmed OVERT limit is exceeded. OVERT can be connected to fans, a system shutdown, a clock throttle control, or other thermal-management circuitry. The MAX6646/MAX6647/MAX6649 convert temperatures to digital data either at a programmed rate or in single conversions. Temperature data is represented as 11 bits, with the LSB equal to 0.125°C. The “main” temperature data registers (at addresses 00h and 01h) are 8-bit registers that represent the data as 8 bits with the full-scale reading indicating the diode fault status (Table 1). The remaining 3 bits of temperature data are available in the “extended” registers at addresses 11h and 10h (Table 2). ADC and Multiplexer The averaging ADC integrates over a 60ms period (each channel, typically), with excellent noise rejection. The multiplexer automatically steers bias currents through the remote and local diodes. The ADC and associated circuitry measure each diode’s forward voltage and compute the temperature based on this voltage. Both channels are automatically converted once the conversion process has started, either in free-running or single-shot mode. If one of the two channels is not used, the device still performs both measurements, and the results of the unused channel can be ignored. If the remote-diode channel is unused, connect DXP to DXN rather than leaving the inputs open. Table 1. Main Temperature Data Register Format (00h, 01h) TEMP (°C) DIGITAL OUTPUT +145 1001 0001 +130 1000 0010 +128 1000 0000 +25 0001 1001 0 0000 0000