MAX819LCSA Maxim Integrated Products, MAX819LCSA Datasheet
MAX819LCSA
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MAX819LCSA Summary of contents
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... Intelligent Instruments Critical µP Monitoring Portable Equipment Typical Operating Circuit appears at end of data sheet. *Patents Pending ________________________________________________________________ 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. ____________________________Features ♦ Precision Supply-Voltage Monitor: 4 ...
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Microprocessor Supervisory Circuits ABSOLUTE MAXIMUM RATINGS Input Voltage V , BATT ..........................................................-0.3V to +6.0V CC All Other Pins (Note 1).............................-0. Input Current V Peak .............................................................................. Continuous .............................................................250mA CC BATT Peak .....................................................................250mA BATT Continuous .............................................................50mA GND ...
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Microprocessor Supervisory Circuits ELECTRICAL CHARACTERISTICS (continued +4.75V to +5.5V for MAX81_L noted. Typical values are +25°C.) A PARAMETER SYMBOL RESET AND WATCHDOG TIMER Reset Threshold V Reset Threshold Hysteresis Reset Timeout Period ...
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Microprocessor Supervisory Circuits ELECTRICAL CHARACTERISTICS (continued +4.75V to +5.5V for MAX81_L noted. Typical values are +25°C.) A PARAMETER SYMBOL CHIP-ENABLE GATING (MAX818 only Leakage Current OUT ...
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Microprocessor Supervisory Circuits __________________________________________Typical Operating Characteristics (V = +5V 3.0V +25°C, unless otherwise noted.) CC BATT A SUPPLY CURRENT vs. TEMPERATURE (NO LOAD -40 - ...
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Microprocessor Supervisory Circuits ____________________________Typical Operating Characteristics (continued +5V 3.0V +25°C, unless otherwise noted.) CC BATT A RESET THRESHOLD vs. TEMPERATURE 4.7 MAX81_L 4.6 4.5 MAX81_M 4.4 4.3 -40 - ...
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Microprocessor Supervisory Circuits ______________________________________________________________Pin Description PIN MAX817 MAX818 MAX819 — 4 — 4 — 5 — 5 — 5 — — — — ...
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Microprocessor Supervisory Circuits BATT V CC THIS PIN FOR MAX819 ONLY. MR WDI THIS SECTION FOR MAX817/ MAX818 ONLY. PFI THIS SECTION FOR MAX817/ MAX819 ONLY. THIS SECTION FOR MAX818 ONLY Figure 1. Functional Diagram 8 _______________________________________________________________________________________ ...
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Microprocessor Supervisory Circuits _______________Detailed Description General Timing Characteristics Designed for 5V systems, the MAX817/MAX818/ MAX819 provide a number of microprocessor (µP) supervisory functions (see the Selector Guide on the first page). Figure 2 shows the typical timing relation- ships ...
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Microprocessor Supervisory Circuits On the MAX819, MR must be high or open to enable the battery freshness seal. Once the battery freshness seal is enabled its operation is unaffected by MR. Watchdog Input (MAX817/MAX818) In the MAX817/MAX818, the watchdog ...
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Microprocessor Supervisory Circuits Any time a reset is generated, the CE transmission gate remains disabled and CE IN remains high impedance (regardless activity) for the reset timeout peri- od. When the CE transmission gate is enabled, ...
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Microprocessor Supervisory Circuits Backup-Battery Switchover In a brownout or power failure, it may be necessary to preserve the contents of RAM. With a backup battery installed at BATT, the MAX817/MAX818/MAX819 auto- matically switch RAM to backup power when V ...
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Microprocessor Supervisory Circuits Watchdog Input Current The MAX817/MAX818 WDI inputs are internally driven through a buffer and series resistor from the watchdog counter (Figure 1). When WDI is left unconnected, the watchdog timer is serviced within the watchdog timeout ...
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Microprocessor Supervisory Circuits desired trip point (V ). Resistor R3 adds hysteresis. TRIP It will typically be an order of magnitude greater than R1 or R2. The current through R1 and R2 should be at least 1µA to ensure ...
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Microprocessor Supervisory Circuits Watchdog Software Considerations (MAX817/MAX818) To help the watchdog timer monitor software execution more closely, set and reset the watchdog input at different points in the program, rather than “pulsing” the watchdog input high-low-high or low-high-low. This ...
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... 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. 16 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 © 2005 Maxim Integrated Products TRANSISTOR COUNT: 719 ...