MAX818MCSA Maxim Integrated, MAX818MCSA Datasheet
MAX818MCSA
Specifications of MAX818MCSA
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MAX818MCSA Summary of contents
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... Intelligent Instruments Critical µP Monitoring Portable Equipment Typical Operating Circuit appears at end of data sheet. *P ________________________________________________________________ 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: 4.65V (MAX81_L) 4.40V (MAX81_M) ♦ ...
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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 .................................................................................25mA Output Current OUT................................................................................250mA All Other Outputs .............................................................25mA OUT Short-Circuit Duration.................................................10sec Note 1: The input voltage limits on PFI and WDI may be exceeded (up to 12V V than 10mA ...
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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 V RESET Output Voltage V to RESET Delay V CC Watchdog 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 Resistance (Note 6) CE OUT Short-Circuit Current (Reset Active OUT Propagation ...
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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 - TEMPERATURE (°C) BATT TO OUT ON-RESISTANCE vs. TEMPERATURE 300 250 V = 2.0V BATT 200 150 V = 2.8V BATT V = 5.0V 100 BATT 50 0 -40 -20 ...
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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 - TEMPERATURE (° OUT PROPAGATION DELAY vs. TEMPERATURE -40 - 100 TEMPERATURE (° ...
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... Microprocessor Supervisory Circuits ______________________________________________________________Pin Description PIN MAX817 MAX818 MAX819 — 4 — 4 — 5 — 5 — 5 — — — — _______________________________________________________________________________________ NAME Supply Output for CMOS RAM. When V OUT or above V , OUT is connected to V BATT MOSFET switch ...
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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 _______________________________________________________________________________________ BATTERY SWITCHOVER CIRCUITRY RESET GENERATOR 1.25V ...
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... V rise and fall times µP’s reset input starts the µ known state. The MAX817/MAX818/MAX819 µP supervisory circuits assert a reset to prevent code-execution errors during power-up, power-down, and brownout conditions. RESET is guaranteed logic low for 0V < V ...
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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 circuit monitors the µP’s activity. If the µP does not toggle the watchdog input (WDI) within t (1 ...
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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, the impedance appears resistor in series with the load at CE OUT. The propagation delay ...
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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 These devices require two conditions before switching to battery-backup mode reset threshold, and 2) 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 period by a low-high-low pulse from the counter chain. ...
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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 that the 25nA (max) PFI input leakage current does not shift the trip point. R3 should be larger than 200k to prevent it from loading down the PFO pin ...
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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 technique avoids a “stuck” loop, in which the watchdog timer would contin reset within the loop, keeping the watchdog from timing out ...
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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 ...