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19-2690; Rev 2; 12/07 Power-Supply Monitor with Reset General Description The MAX700/MAX701/MAX702 are supervisory circuits used to monitor the power supplies in microprocessor (P) and digital systems. The RESET/RESET outputs of the MAX700/MAX701/MAX702 are guaranteed to be in the correct state for VCC voltages down to +1V (Figure 4). They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V-powered circuits. The MAX702 is the simplest part in the family. When VCC falls to 4.65V, RESET goes low. The MAX702 also provides a debounced manual reset input. The MAX701 performs the same functions but has both RESET and RESET outputs. Their primary function is to provide a system reset. Accordingly, an active reset signal is supplied for low supply voltages and for at least 200ms after the supply voltage reaches its operating value. In addition to the features of the MAX701 and MAX702, the MAX700 provides preset or adjustable voltage detection so thresholds other than 4.65V can be selected, and adjustable hysteresis. All parts are supplied in 8-pin PDIP and Narrow SO packages in commercial and extended temperature ranges. Features Min 200ms RESET Pulse on Power-Up, PowerDown, and During Low-Voltage Conditions Reset Threshold Factory Trimmed for +5V Systems No External Components or Adjustments with +5V-Powered Circuits Debounced Manual Reset Input Preset or Adjustable Voltage Detection (MAX700) Adjustable Hysteresis (MAX700) 8-Pin PDIP and Narrow SO Packages MAX700/MAX701/MAX702 Ordering Information PART* MAX700C/D MAX700CPA MAX700CSA MAX700EPA MAX700ESA MAX701C/D MAX701CPA MAX701CSA MAX701EPA MAX701ESA MAX702C/D MAX702CPA MAX702CSA MAX702EPA TEMP RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C PIN-PACKAGE Dice 8 PDIP 8 Narrow SO 8 PDIP 8 Narrow SO Dice 8 PDIP 8 Narrow SO 8 PDIP 8 Narrow SO Dice 8 PDIP 8 Narrow SO 8 PDIP Applications Computers Controllers Intelligent Instruments Automotive Systems Critical P Power Monitoring MAX702ESA -40C to +85C 8 Narrow SO *Devices in PDIP and SO packages are available in both leaded and lead-free packaging. Specify lead free by adding the + symbol at the end of the part number when ordering. Pin Configurations TOP VIEW MR 1 SENSE 2 8 7 VCC CTL RESET RESET MR 1 N.C. 2 8 7 VCC N.C. RESET RESET MR VCC GND 1 2 8 7 N.C. RESET N.C. N.C. MAX700 HYST 3 6 5 N.C. 3 GND 4 GND 4 MAX701 6 5 MAX702 3 6 5 N.C. 4 DIP/SO DIP/SO DIP/SO 1 ________________________________________________________________ Maxim Integrated Products 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. Power-Supply Monitor with Reset MAX700/MAX701/MAX702 ABSOLUTE MAXIMUM RATINGS VCC ......................................................................-0.3V to +15.5V Voltage (with respect to GND) at RESET, RESET, HYST, CTL, SENSE ............................................-0.3V to VCC Operating Temperature Range C Suffix .............................................................0C to +70C E Suffix...........................................................-40C to +85C Rate of Rise, VCC ............................................................100V/s Power Dissipation, Any Package .....................................380mW Storage Temperature Range .............................-55C to +150C Lead Temperature (soldering, 10s)..................................+300C 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 = +5V, CTL = GND on MAX700, TA = +25C, unless otherwise noted.) PARAMETER VCC Monitor Voltage Range (MAX700 Only) Min VCC for Valid Reset Output, Declining Supply Supply Current Reset Threshold Internal Hysteresis Reset Output Pulse Width RESET Fall Time VCC Pulse Duration Guaranteeing MR Input Threshold MR Pullup Current MAX700 RESET Output Low ISINK = 3.2mA, VCC = 5V ISINK = 1.6mA, VCC = 3V ISOURCE = 3.2mA, VCC = 4.25V RESET Output High ISOURCE = 1.6mA, VCC = 3V ISOURCE = 0.5mA, VCC = 1.5V ISINK = 16mA, VCC = 4.25V RESET Output Low ISINK = 1.6mA, VCC = 3V ISINK = 0.4mA, VCC = 1.5V ISOURCE = 3.2mA, VCC = 5V RESET Output High ISOURCE = 1.6mA, VCC = 3V VCC 0.4 V VCC 0.4 VCC 0.4 VCC 0.4 VCC 0.4 0.4 0.4 0.4 V V 0.4 0.4 V MAX700/MAX701 only, CLOAD = 100pF 5V to 4V VCC pulse No reset Reset 100 TA = TMIN to TMAX HYST not connected 200 Power-up Power-down 4.50 4.50 CONDITIONS TA = TMIN to TMAX, CTL = VCC TA = TMIN to TMAX, RESET 0.4V when sinking 1mA MIN 3 1.5 1 100 4.65 4.62 30 350 200 10 10 0.7 -5 -30 1 500 200 4.75 4.75 TYP MAX 15 UNITS V V A V mV ms ns s V A 2 _______________________________________________________________________________________ Power-Supply Monitor with Reset ELECTRICAL CHARACTERISTICS (continued) (VCC = +5V, CTL = GND on MAX700, TA = +25C, unless otherwise noted.) PARAMETER MAX701 RESET Output Low ISINK = 16mA, VCC = 5V ISOURCE = 3.2mA, VCC = 4.25V RESET Output High ISOURCE = 1.6mA, VCC = 3V ISOURCE = 0.5mA, VCC = 1.5V ISINK = 3.2mA, VCC = 4.25V RESET Output Low ISINK = 1.6mA, VCC = 3V ISINK = 0.4mA, VCC = 1.5V RESET Output High MAX702 ISINK = 3.2mA, VCC = 4.25V RESET Output Low ISINK = 1.6mA, VCC = 3V ISINK = 0.4mA, VCC = 1.5V RESET Output High ISOURCE = 3.2mA, VCC = 5V VCC 0.4 1.25 1.29 0.1 0.5 2 30 100 1.35 0.4 0.4 0.4 V V ISOURCE = 3.2mA, VCC = 5V VCC 0.4 VCC 0.4 VCC 0.4 VCC 0.4 0.4 0.4 0.4 V V V 0.4 V CONDITIONS MIN TYP MAX UNITS MAX700/MAX701/MAX702 MAX700 ONLY (CTL = VCC, unless otherwise noted) SENSE Input Threshold SENSE Input Current HYST Input On-Resistance CTL Input Threshold CTL Pulldown Current TA = TMIN to TMAX V nA k V A _______________________________________________________________________________________ 3 Power-Supply Monitor with Reset MAX700/MAX701/MAX702 Pin Description PIN MAX700 1 MAX701 1 MAX702 1 NAME MR FUNCTION Input for Manual Pushbutton Reset. Has internal 5A pullup. Low input activates the RESET/RESET outputs. The voltage-sense input when CTL = VCC. Its threshold is 1.29V. SENSE always remains connected to the internal comparator. So, when VCC is being monitored internally (CTL = GND), SENSE should be left open circuit. Normally NOT used when voltage is monitored through VCC (CTL = GND). When monitoring through SENSE (CTL = VCC), HYST allows hysteresis to be added, reducing noise and spurious reset activity (Figure 3). HYST turns on 5s before the RESET/RESET outputs are activated, and its on-resistance to GND is typically 1k. Ground Goes low when VCC falls below 4.65V, or when CTL = VCC on the MAX700 goes low when SENSE falls below 1.29V. Inverted Version of RESET When CTL = GND, VCC is monitored by the reset circuit. When CTL = VCC, VCC is ignored and SENSE is monitored, allowing the threshold to be set with external resistors. Chip Power and +5V Sensing Input (When CTL = GND on MAX700) No Connection 2 -- -- SENSE 3 -- -- HYST 4 5 6 7 8 -- 4 6 5 -- 8 2, 3, 7 3 7 -- -- 2 4, 5, 6, 8 GND RESET RESET CTL VCC N.C. 4 _______________________________________________________________________________________ Power-Supply Monitor with Reset MAX700/MAX701/MAX702 MR 1 1M 8 VCC 7 COMPARATOR SENSE 2 150k CTL MANUAL RESET BUTTON 1 N.C. 2 3 MR SENSE HYST GND MAX700 VCC CTL RESET RESET 8 7 6 5 +5V MAX700 1.29V REF R RC 6 R OSC HYST 3 5 4 RESET RESET N.C. TO P 4 GND Figure 1. MAX700 Block Diagram Figure 2. MAX700 Typical Connection Diagram MANUAL RESET BUTTON 1 R1 VIN R2 R3 3 4 HYST GND RESET RESET 6 5 N.C. TO P 2 MR SENSE MAX700 VCC CTL 8 7 VIN 3V TO 15V RESET 2V/div 0V VCC R1 = R2 VL - 1 VL = LOWER VOLTAGE THRESHOLD 1.29 VTR1 R3 = V = UPPER VOLTAGE THRESHOLD VU - V L U 2V/div ( ) 0V 1s/div HYSTERESIS = VU - VL Figure 3. MAX700 Connected for External Senses and Hysteresis Figure 4. Typical MAX700/MAX701/MAX702 RESET Output vs. VCC Figure 4 shows the RESET output of the MAX700/ MAX701/MAX702 in the correct state for VCC voltages down to 0V. Note the effect of the built-in hysteresis on the trigger lever of RESET. Package Information For the latest package outline information, go to www.maxim-ic.com/packages. _______________________________________________________________________________________ 5 Power-Supply Monitor with Reset MAX700/MAX701/MAX702 Revision History REVISION NUMBER 0 1 2 REVISION DATE 3/90 11/05 12/07 Initial release Added lead-free information to the Ordering Information table. Updated Pin Description table. DESCRIPTION PAGES CHANGED -- 1 4 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. 6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc. |
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