www.DataSheet4U.com 19-2459; Rev 2; 4/03 Dual-Output Remote-Junction Temperature Switches Features ♦ Pin-Programmed Lower Temperature Threshold from +40°C to +80°C or +75°C to +115°C (5°C Increments) ♦ Preset Upper Threshold: +120°C or +125°C ♦ Open-Drain, Active-Low Output for Upper Temperature Alarm ♦ CMOS Push-Pull, Active-High or Open-Drain, Active-Low Output for Lower Temperature Alarm ♦ 1.5°C Accuracy ♦ 3.0V to 5.5V, 200µA Supply ♦ 8-Pin µMAX Package Applications CPU Temperature Protection Fan Control Multichip Modules FPGA Temperature Protection Pin Configurations appear at end of data sheet. Ordering Information TLOW OUTPUT PART TLOW TRIP RANGE (0°C) THIGH TRIP THRESHOLD (0°C) PIN-PACKAGE MAX6685AU40L Push-pull, active high +40°C to +80°C +120°C 8 µMAX MAX6685AU40H Push-pull, active high +40°C to +80°C +125°C 8 µMAX MAX6685AU75L Push-pull, active high +75°C to +115°C +120°C 8 µMAX MAX6685AU75H Push-pull, active high +75°C to +115°C +125°C 8 µMAX MAX6686AU40L Open drain, active low +40°C to +80°C +120°C 8 µMAX MAX6686AU40H Open drain, active low +40°C to +80°C +125°C 8 µMAX MAX6686AU75L Open drain, active low +75°C to +115°C +120°C 8 µMAX MAX6686AU75H Open drain, active low +75°C to +115°C +125°C 8 µMAX Typical Operating Circuits 3.3V DXP CPU CS VDD 3.3V TO SYSTEM SHUTDOWN THIGH 12V DXP CPU CS MAX6685 DXN S1 VDD THIGH MAX6686 DXN S1 TLOW S2 GND N TO SYSTEM SHUTDOWN TLOW S2 GND TO CLOCK THROTTLE CONTROL ________________________________________________________________ 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 MAX6685/MAX6686 General Description MAX6685/MAX6686 are dual-output temperature switches that use an external diode-connected transistor as a sensing element. These devices have two logic outputs (THIGH and TLOW). THIGH asserts a logic signal when the remote temperature crosses the factory-programmed, +120°C, or +125°C upper trip threshold. TLOW is asserted when the remote temperature exceeds the lower threshold, which is controlled by pins S1 and S2. The lower 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. Hysteresis for both outputs to be deasserted is typically 5°C. THIGH is an open-drain, active-low output for both the MAX6685 and the MAX6686. TLOW is a CMOS push-pull, active-high output for the MAX6685 and is an open-drain, active-low output for the MAX6686. They are available in a space-saving 8-pin µMAX package. MAX6685/MAX6686 Dual-Output Remote-Junction Temperature Switches ABSOLUTE MAXIMUM RATINGS Voltages Referenced to GND VDD, TLOW, THIGH .....................................................-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 = 3.0V 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 POR VDD falling edge 1.0 POR Threshold Hysteresis Temperature Threshold Accuracy 5.5 V 200 500 µA 400 800 µA 1.5 2.0 V 50 ∆TTH VDD = 3.3V, TA = +25°C, TRJ = 0°C to +125°C (Note 2) -1.5 TA = 0°C to +100°C, TRJ = 0°C to +125°C Temperature Threshold Hysteresis MAX 3.0 Supply Current During Conversion Power-On Reset Threshold TYP mV +1.5 °C 2.0 THYST Supply Sensitivity of Temperature Threshold UNITS 5.0 TA = +25°C, TRJ = 0°C to +125°C, VDD = 3.0V to 5.5V °C 0.6 VDD 0.2 °C/V Output Voltage High VOH ISOURCE = 1mA, MAX6685 TLOW only Output Voltage Low VOL ISINK = 1mA 0.2 V Logic-Low Input Voltage VIL S1, S2 0.4 V Logic-High Input Voltage VIH S1, S2 V 1.8 V Input Current S1, S2 10 µA Open-Drain Output Leakage Current VOUT = 5.5V, TLOW and THIGH 1 µA Conversion Time 0.09 0.11 0.13 s Sample Period 0.35 0.45 0.55 s High level 80 100 120 Low level 8 10 12 Current Sourcing for External Diode 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. Note 2: TRJ is the temperature of the remote-sensing diode junction. 2 _______________________________________________________________________________________ Dual-Output Remote-Junction Temperature Switches AVERAGE SUPPLY CURRENT vs. SUPPLY VOLTAGE 140 120 200 10 TEMPERATURE TRIP THRESHOLD ERROR (°C) AVERAGE SUPPLY CURRENT (µA) 160 MAX6685 toc02 250 MAX6685 toc01 180 150 100 50 MAX6685U40H S1 = S2 = GND 8 6 4 2 0 100 25 50 75 100 0 3.0 125 3.5 4.0 4.5 5.5 0 10 SUPPLY VOLTAGE (V) AMBIENT TEMPERATURE (°C) UPPER TEMPERATURE TRIP THRESHOLD ERROR vs. AMBIENT TEMPERATURE 2.0 MAX6685U40H THIGH TRIP = +125°C 1.6 5.0 1.2 0.8 0.4 0 -0.4 -0.8 -1.2 -1.6 20 30 40 50 60 CS CAPACITANCE (nF) LOWER TEMPERATURE TRIP THRESHOLD ERROR vs. AMBIENT TEMPERATURE 2.0 MAX6685 toc05 0 LOWER TRIP THRESHOLD ERROR (°C) -25 MAX6685 toc04 -50 UPPER TRIP THRESHOLD ERROR (°C) AVERAGE SUPPLY CURRENT (µA) 200 TEMPERATURE TRIP THRESHOLD ERROR vs. CS CAPACITANCE MAX6685 toc03 AVERAGE SUPPLY CURRENT vs. AMBIENT TEMPERATURE MAX6685U40H S1 = S2 = VDD 1.6 1.2 0.8 0.4 0 -0.4 -0.8 -1.2 -1.6 -2.0 -2.0 -50 -25 0 25 50 75 AMBIENT TEMPERATURE (°C) 100 125 -50 -25 0 25 50 75 100 125 AMBIENT TEMPERATURE (°C) _______________________________________________________________________________________ 3 MAX6685/MAX6686 Typical Operating Characteristics (VDD = 3.3V, CS = 2200pF, TA = +25°C, unless otherwise noted. See Typical Operating Circuits.) MAX6685/MAX6686 Dual-Output Remote-Junction Temperature Switches Pin Description PIN MAX6685 MAX6686 NAME FUNCTION 1 1 VDD Power-Supply Input. Bypass to GND with a 0.1µF capacitor. 2 2 GND Ground 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 with the shortest possible connection. 5 5 THIGH Open-Drain, Active-Low Output. THIGH goes low when the temperature exceeds the factoryprogrammed upper temperature threshold, either +120°C or +125°C. Connect a pullup resistor (typically 10kΩ) between THIGH and a positive supply up to 5.5V. 6 — TLOW CMOS Push-Pull, Active-High Output. TLOW goes HIGH when the temperature exceeds the pinprogrammed lower temperature threshold. — 6 TLOW Open-Drain, Active-Low Output. TLOW goes LOW when the temperature exceeds the pinprogrammed lower temperature threshold. Connect a pullup resistor (typically 10kΩ) between TLOW and a positive supply up to 5.5V. 7 7 S1 Threshold Select Input. Used in conjunction with S2 to set the lower threshold for TLOW (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 lower threshold for TLOW (Table 1). It can be connected to VDD, GND, or left floating. Detailed Description The MAX6685/MAX6686 dual-output remote-sensing junction temperature switches incorporate a precision remote-junction temperature sensor and two comparators. These devices use an external P-N junction as the temperature-sensing element (see Typical Operating Circuits). The MAX6685/MAX6686 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. The 5°C hysteresis keeps the outputs from “chattering” when the measured temperature is close to the threshold temperature. The MAX6685/MAX6686 are available with preset upper temperature thresholds of +120°C or +125°C. The lower temperature thresholds are pin programmable in 5°C increments (Table 1). Two tempera- 4 ture ranges are available for the lower trip 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 this is done after the power is turned on, the lower trip threshold remains set to the point where S1 and S2 were when power was applied. Applications Information Remote-Diode Selection The MAX6685/MAX6686 are optimized to measure the die temperature of CPUs and other ICs that have on-chip 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 Vbe characteristics. Always use a transistor for the sensing junction; diodes do not work. _______________________________________________________________________________________ Dual-Output Remote-Junction Temperature Switches MAX6685/MAX6686 Table 1. Lower Temperature Trip Threshold Selection S1 S2 MAX6685AUA40L MAX6685AUA40H MAX6686AUA40L MAX6686AUA40H MAX6685AUA75L MAX6685AUA75H MAX6686AUA75L MAX6686AUA75H LOWER TEMPERATURE TRIP THRESHOLD (°C) LOWER TEMPERATURE TRIP THRESHOLD (°C) +40 +75 GND GND GND FLOAT +45 +80 GND VDD +50 +85 +90 FLOAT GND +55 FLOAT FLOAT +60 +95 FLOAT VDD +65 +100 VDD GND +70 +105 VDD FLOAT +75 +110 VDD VDD +80 +115 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% variation from the recommended capacitor value can cause up to ±1°C error. Table 2. Sensor Transistor Manufacturers MANUFACTURER MODEL NO. Central Semiconductor (USA) CMPT3904 ON Semiconductor (USA) 2N3904, 2N3906 Rohm Semiconductor (Japan) SST3904 Samsung (Korea) KST3904-TF Siemens (Germany) SMBT3904 Note: Discrete transistors must be diode connected (base shorted to collector). VDD VDD THIGH THIGH +120°C OR +125°C THIGH THIGH +120°C OR +125°C N N DXP DXN S1 S2 REMOTE TEMPERATURE CONVERTER DXP DXN DIGITAL DRIVER TLOW +40°C TO +115°C TLOW S1 S2 GND MAX6685 Figure 1. MAX6685 Functional Diagram REMOTE TEMPERATURE CONVERTER TLOW N TLOW +40°C TO +115°C GND MAX6686 Figure 2. MAX6686 Functional Diagram _______________________________________________________________________________________ 5 MAX6685/MAX6686 Dual-Output Remote-Junction Temperature Switches Pin Configurations Chip Information TRANSISTOR COUNT: 7765 PROCESS: BiCMOS TOP VIEW VDD 1 GND 2 8 S2 VDD 1 7 S1 GND 2 MAX6685 S2 7 S1 MAX6686 3 6 TLOW DXP 3 6 TLOW DXN 4 5 THIGH DXN 4 5 THIGH DXP µMAX 6 8 µMAX _______________________________________________________________________________________ Dual-Output Remote-Junction Temperature Switches 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. MAX6685/MAX6686 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.)