19-2636; Rev 2; 11/03 Local/Remote Temperature Switches in a µMAX Package Features ♦ Pin-Programmable Local Temperature Threshold in 5°C Increments in Two Distinct Ranges: +40°C to +80°C and +75°C to +115°C The MAX6687 has two open-drain active-low outputs while the MAX6688 has two push-pull active-high outputs. TREMOTE asserts a logic signal when the remote temperature exceeds the factory-programmed +120°C or +125°C trip threshold. TLOCAL is asserted when the die temperature exceeds the pin-programmed threshold, which is controlled by pins S1 and S2. The local thresholds are available in two ranges in 5°C increments. The two ranges are +40°C to +80°C and +75°C to +115°C. The MAX6687/MAX6688 operate from a 3.0V to 5.5V power supply and are available in a space-saving 8-pin µMAX package. ♦ 8-Pin µMAX Package Applications CPU Temperature Protection FPGA Temperature Protection ♦ Factory-Programmed Remote Threshold: +120°C (L Suffix) or +125°C (H Suffix) ♦ Open-Drain Active-Low Outputs (MAX6687) ♦ CMOS Push-Pull, Active-High Outputs (MAX6688) ♦ ±1.5°C Accuracy ♦ 2Hz Temperature Sampling Rate ♦ 215µA Average Supply Current ♦ 3.0V to 5.5V Power-Supply Voltage Ordering Information PART TEMP RANGE PIN-PACKAGE MAX6687AU40L -40°C to +125°C 8 µMAX MAX6687AU40H -40°C to +125°C 8 µMAX MAX6687AU75L -40°C to +125°C 8 µMAX MAX6687AU75H -40°C to +125°C 8 µMAX MAX6688AU40L -40°C to +125°C 8 µMAX MAX6688AU40H -40°C to +125°C 8 µMAX MAX6688AU75L -40°C to +125°C 8 µMAX MAX6688AU75H -40°C to +125°C 8 µMAX Pin Configurations/Functional Diagrams/Selector Guide appear at end of data sheet. Fan Control Temperature Alarms Typical Operating Circuit 3.3V DXP 3.3V VDD DXP MAX6687 CS DXN µP 3.3V CS TLOCAL S2 TREMOTE 12V MAX6688 DXN TREMOTE S1 TO SYSTEM SHUTDOWN VDD TO SYSTEM SHUTDOWN µP S1 S2 TLOCAL GND N GND ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX6687/MAX6688 General Description The MAX6687/MAX6688 comprise a remote-junction temperature switch and a local temperature switch in a single package. The remote-junction switch uses an external P-N junction (typically a diode-connected transistor on the die of an external CPU, ASIC, or FPGA) as a sensing element to measure the remote temperature. The remote-junction temperature switch has a factoryprogrammed trip temperature threshold of either +120°C or +125°C. The local temperature switch has a pin-programmable temperature threshold that is set by connecting pins S1 and S2 to ground, to VDD, or leaving them floating. Hysteresis for both local and remote thresholds is 5°C. The MAX6687/MAX6688 do not assert on transient (single-sample) faults or when power is first applied. MAX6687/MAX6688 Local/Remote Temperature Switches in a µMAX Package ABSOLUTE MAXIMUM RATINGS Voltages Referenced to GND VDD, TLOCAL, TREMOTE ............................................-0.3V to +6V DXN .......................................................................-0.3V to +0.8V All Other Pins..............................................-0.3V to (VDD + 0.3V) Input Current .........................................................................5mA Output Current ....................................................................20mA Continuous Power Dissipation (TA = +70°C) 8-Pin µMAX (derate 4.1mW/°C above +70°C) .............330mW Operating Temperature Range .........................-40°C to +125°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +165°C Lead Temperature (soldering, 10s) .................................+300°C 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 (VDD = 3V to 5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VDD = 3.3V and TA = +25°C.) (Note 1) PARAMETER SYMBOL Power-Supply Range VDD Average Supply Current IDD CONDITION MIN Supply Current During Conversion Power-On Reset (POR) Threshold POR VDD falling edge 1 POR Threshold Hysteresis Remote-Diode Temperature Threshold Accuracy, Rising Temperature Internal Temperature Threshold Accuracy, Rising Temperature Temperature Threshold Hysteresis TYP MAX UNITS 5.5 V 215 500 µA 400 800 µA 1.5 2.0 V 3 50 ∆TTH ∆TTH -1.5 +1.5 TA = 0°C to +85°C, VDD = 3.3V -3.0 +3.0 TA = -40°C to +125°C, VDD = 3.3V -5.0 +5.0 Temperature trip thresholds from +40°C to +105°C, VDD = 3.3V -3.0 +3.0 Temperature trip thresholds +110°C and +115°C, VDD = 3.3V -3.5 +3.5 VOH ISOURCE = 1mA, MAX6688 Output Voltage Low VOL ISINK = 1mA Logic Input Low Voltage (S1, S2) VIL Logic Input High Voltage (S1, S2) VIH 0.6 °C/V 0.2 V 0.4 V VDD - 0.2 V 1.8 Input Current (S1, S2) 2 °C 5.0 THYST Output Voltage High °C °C Temperature Threshold Supply Sensitivity Open-Drain Output Leakage Current mV TA = +25°C, VDD = 3.3V VOUT = 5.5V, MAX6687 _______________________________________________________________________________________ V 10 µA 1 µA Local/Remote Temperature Switches in a µMAX Package (VDD = 3V to 5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VDD = 3.3V and TA = +25°C.) (Note 1) MIN TYP MAX UNITS Temperature Conversion Time PARAMETER SYMBOL 0.2 0.25 0.3 s Temperature Sample Period 0.4 0.5 0.6 s High level 80 100 120 Low level 8 10 12 Current Sourcing for External Diode CONDITION µA Note 1: All parameters are tested at +25°C. Temperature specifications over a range of -40°C to +125°C are guaranteed by design. Typical Operating Characteristics (VDD = 3.3V, CS = 2200pF, TA = +25°C, unless otherwise noted.) AVERAGE SUPPLY CURRENT vs. SUPPLY VOLTAGE AVERAGE SUPPLY CURRENT vs. AMBIENT TEMPERATURE 220 180 140 100 -50 -25 0 25 50 75 100 MAX6687/88 toc02 260 300 AVERAGE SUPPLY CURRENT (µA) MAX6687/88 toc01 AVERAGE SUPPLY CURRENT (µA) 300 TA = +100°C 260 220 180 TA = -40°C TA = +25°C 140 100 125 3.0 AMBIENT TEMPERATURE (°C) 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 1 0 MAX6687/88 toc04 MAX6688U40H S1 = S2 = FLOAT 4.0 REMOTE TEMPERATURE TRIP THRESHOLD ERROR vs. AMBIENT TEMPERATURE UPPER TRIP THRESHOLD ERROR (°C) 4.5 MAX6687/88 toc03 TEMPERATURE TRIP THRESHOLD ERROR (°C) TEMPERATURE TRIP THRESHOLD ERROR vs. CS CAPACITANCE MAX6688U40H TREMOTE TRIP = +125°C -1 -2 -3 -4 -5 1 10 CS CAPACITANCE (nF) 100 -50 -25 0 25 50 75 100 AMBIENT TEMPERATURE (°C) _______________________________________________________________________________________ 3 MAX6687/MAX6688 ELECTRICAL CHARACTERISTICS (continued) Local/Remote Temperature Switches in a µMAX Package MAX6687/MAX6688 Pin Description PIN NAME FUNCTION MAX6687 MAX6688 1 1 VDD 2 2 GND Ground Power-Supply Input. Bypass to GND with a 0.1µF capacitor. 3 3 DXP This pin connects to the positive (anode) terminal of the external P-N sense junction. It sources current into the external junction. A 2200pF capacitor should be connected across DXP and DXN. 4 4 DXN This pin connects to the negative (cathode) terminal of the external P-N sense junction. It sinks current from the external junction. A 2200pF capacitor should be connected across DXP and DXN. DXN must be connected to the GND pin at the pin. 5 — TREMOTE Open-Drain Active-Low Output. TREMOTE goes low when the temperature exceeds the factoryprogrammed temperature threshold, either +120°C or +125°C. Connect a pullup resistor (typically 10kΩ) between TREMOTE and a positive power supply up to 5.5V. — 5 TREMOTE CMOS Push-Pull, Active-High Output. TREMOTE goes high when the temperature exceeds the factory-programmed temperature threshold, either +120°C or +125°C. 6 — TLOCAL Open-Drain Active-Low Output. TLOCAL goes low when the temperature exceeds the pinprogrammable temperature threshold set by S1 and S2. Connect a pullup resistor (typically 10kΩ) between TLOCAL and a positive power supply up to 5.5V. — 6 TLOCAL CMOS Push-Pull, Active-High Output. TLOCAL goes high when the temperature exceeds the pin-programmable temperature threshold set by S1 and S2. 7 7 S1 Threshold Select Input. Used in conjunction with S2 to set the local threshold temperature (Table 1). It can be connected to VDD, GND, or left floating. 8 8 S2 Threshold Select Input. Used in conjunction with S1 to set the local threshold temperature (Table 1). It can be connected to VDD, GND, or left floating. Detailed Description The MAX6687/MAX6688 sense the temperatures of both a remote P-N junction and their own die. The external P-N junction is typically a base-emitter junction of a substrate PNP on a microprocessor, FPGA, or ASIC die (see the Typical Operating Circuit). The remote temperature switch has a factory-programmed trip temperature of either +120°C or +125°C and is intended to be used for system shutdown when the die temperature of a remote IC, such as a microprocessor, FPGA, or ASIC exceeds the factory-programmed thresholds. The local temperature switch has a pin-programmable threshold temperature (Table 1). This temperature switch may be used for such functions as system shutdown or for turning on a cooling fan when board temperature exceeds the temperature limit. Two temperature ranges are available for the local trip 4 threshold: +40°C to +80°C and +75°C to +115°C. S1 and S2 pins must be set to the desired trip temperature before power is applied to the VDD pin. If S1 and S2 settings are changed after the power is turned on, the local trip threshold remains set to the point where S1 and S2 were when power was applied. Since the MAX6687/MAX6688 are often used for system shutdown, they are designed so that the outputs do not change on transient faults or when power is first applied. This eliminates the possibility that the IC could erroneously shut a system down. The MAX6687/MAX6688 provide noise immunity by integration and oversampling of the diode voltage, but good design practice includes routing the DXP and DXN lines away from noise sources, such as highspeed digital lines, switching regulators, inductors, and transformers. The DXP and DXN traces should be paired together and surrounded by a ground plane whenever possible. _______________________________________________________________________________________ Local/Remote Temperature Switches in a µMAX Package S1 MAX6687AUA40L/MAX6687AUA40H/ MAX6688AUA40L/MAX6688AUA40H MAX6687AUA75L/MAX6687AUA75H/ MAX6688AUA75L/MAX6688AUA75H LOCALTEMPERATURE TRIP THRESHOLD (°C) LOCAL TEMPERATURE TRIP THRESHOLD (°C) S2 GND GND +40 +75 GND FLOAT +45 +80 GND VDD +50 +85 FLOAT GND +55 +90 FLOAT FLOAT +60 +95 FLOAT VDD +65 +100 VDD GND +70 +105 VDD FLOAT +75 +110 VDD VDD +80 +115 Applications Information Remote-Diode selection The MAX6687/MAX6688 are optimized to measure the die temperature of CPUs and other ICs that have onchip temperature-sensing diodes. These on-chip diodes are substrate PNPs with their collectors grounded. Connect the base of the PNP to DXN and the emitter to DXP. When using a discrete, diode-connected NPN or PNP as a sensing diode, use a good-quality small-signal device. Examples are listed in Table 2. Tight specifications for forward current gain indicate the manufacturer has good process controls and that the devices have consistent V BE characteristics. Always use a transistor for the sensing junction; diodes do not work. The MAX6687/MAX6688 are optimized for use with thermal-sensing transistors with an ideality factor of 1.008. Different ideality factors cause predictable, usually small deviations in trip temperature thresholds. Table 2. Sensor Transistor Manufacturers MANUFACTURER MODEL NO. Central Semiconductor (USA) CMPT3904 Rohm Semiconductor (Japan) SST3904 Samsung (Korea) KST3904-TF Siemens (Germany) SMBT3904 Noise-Filtering Capacitors A quality ceramic capacitor must be connected across the DXP/DXN inputs to maintain temperature threshold accuracy by filtering out noise. The capacitor should be located physically close to the DXP/DXN pins and should typically have a value of 2200pF. Larger capacitor values can cause temperature measurement errors. A 50% increase from the recommended capacitor value can cause up to ±1°C error. Sensing Circuit Board and Ambient Temperature Temperature switches like the MAX6687/MAX6688 that sense their own die (local) temperatures must be mounted on or close to the object whose temperature they are intended to measure. The MAX6687/MAX6688 can accurately measure the temperature of a circuit board to which they are soldered because the package leads provide a good thermal path between the circuit board and their own die. If the MAX6687/MAX6688 are intended to be triggered by the temperature of a heatgenerating component on the circuit board, they should be mounted as close as possible to that component and should share supply and ground traces (if they are not noisy) with that component where possible. The thermal path between the plastic package and the die is not as good as the path through the package leads, so the MAX6687/MAX6688 are less sensitive to the surrounding air temperature than they are to the temperature of their package leads, but they can be successfully used to respond to the ambient temperature if the circuit board is designed to track the ambient temperature. Chip Information TRANSISTOR COUNT: 7765 PROCESS: BiCMOS _______________________________________________________________________________________ 5 MAX6687/MAX6688 Table 1. Local Temperature Trip Threshold Selection Local/Remote Temperature Switches in a µMAX Package MAX6687/MAX6688 Pin Configurations TOP VIEW VDD 1 GND 2 8 S2 VDD 1 7 S1 GND 2 MAX6687 DXP 8 S2 7 S1 MAX6688 3 6 TLOCAL DXP 3 6 TLOCAL DXN 4 5 TREMOTE DXN 4 5 TREMOTE µMAX µMAX Functional Block Diagrams VDD VDD TREMOTE TREMOTE +120°C OR +125°C DXP DXN TREMOTE +120°C OR +125°C N DXP REMOTE TEMPERATURE CONVERTER MAX6687 DXN DIGITAL DRIVER REMOTE TEMPERATURE CONVERTER TREMOTE MAX6688 LOCAL TEMPERATURE CONVERTER LOCAL TEMPERATURE CONVERTER TLOCAL S1 N TREMOTE +40°C OR +115°C DIGITAL DRIVER S1 TREMOTE +40°C OR +115°C TLOCAL S2 S2 GND GND Figure 1a. MAX6687 Functional Block Diagram Figure 1b. MAX6688 Functional Block Diagram Selector Guide 6 PART OUTPUTS REMOTE TRIP THRESHOLD (°C) LOCAL TRIP THRESHOLD RANGE (°C) MAX6687AU40L Open drain, active low +120 +40 to +80 MAX6687AU40H Open drain, active low +125 +40 to +80 MAX6687AU75L Open drain, active low +120 +75 to +115 MAX6687AU75H Open drain, active low +125 +75 to +115 MAX6688AU40L Push pull, active high +120 +40 to +80 MAX6688AU40H Push pull, active high +125 +40 to +80 MAX6688AU75L Push pull, active high +120 +75 to +115 MAX6688AU75H Push pull, active high +125 +75 to +115 _______________________________________________________________________________________ Local/Remote Temperature Switches in a µMAX Package 8 INCHES DIM A A1 A2 b E ÿ 0.50±0.1 H c D e E H 0.6±0.1 L 1 1 α 0.6±0.1 S BOTTOM VIEW D MIN 0.002 0.030 MAX 0.043 0.006 0.037 0.014 0.010 0.007 0.005 0.120 0.116 0.0256 BSC 0.120 0.116 0.198 0.188 0.026 0.016 6∞ 0∞ 0.0207 BSC 8LUMAXD.EPS 4X S 8 MILLIMETERS MAX MIN 0.05 0.75 1.10 0.15 0.95 0.25 0.36 0.13 0.18 2.95 3.05 0.65 BSC 2.95 3.05 4.78 5.03 0.41 0.66 0∞ 6∞ 0.5250 BSC TOP VIEW A1 A2 A α c e b L SIDE VIEW FRONT VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, 8L uMAX/uSOP APPROVAL DOCUMENT CONTROL NO. 21-0036 REV. J 1 1 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX6687/MAX6688 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)