MAX691A MAXIM [Maxim Integrated Products], MAX691A Datasheet
MAX691A
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MAX691A Summary of contents
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... Features include write pro- tection of CMOS RAM or EEPROM, separate watchdog outputs, backup-battery switchover, and a RESET out- put that is valid with V down to 1V. The MAX691A/ CC MAX800L have a 4.65V typical reset-threshold voltage, and the MAX693A/MAX800M’s reset threshold is 4.4V typical. The MAX800L/MAX800M guarantee power-fail accuracies to ± ...
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... 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 (MAX691A, MAX800L +4.75V to +5.5V, MAX693A, MAX800M unless otherwise noted.) ...
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... Microprocessor Supervisory Circuits ELECTRICAL CHARACTERISTICS (continued) (MAX691A, MAX800L +4.75V to +5.5V, MAX693A, MAX800M unless otherwise noted.) PARAMETER Battery Switchover Hysteresis I = 3.2mA BATT ON Output SINK Low Voltage I = 25mA SINK Sink current BATT ON Output Short-Circuit Current Source current RESET AND WATCHDOG TIMER MAX691A, MAX800L ...
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... External Capacitor Note 1: Either V or VBATT can go to 0V, if the other is greater than 2.0V. CC Note 2: The supply current drawn by the MAX691A/MAX800L/MAX800M from the battery excluding I when (VBATT - 1V) < V < VBATT. In most applications, this is a brief period Note 3: “+” = battery-discharging current, “--” = battery-charging current. ...
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... VBATT to V ON-RESISTANCE OUT vs. TEMPERATURE 20 VBATT = 2.0V 15 VBATT = 2.8V 10 VBATT = 4. -60 - 120 150 TEMPERATURE (°C) RESET THRESHOLD vs. TEMPERATURE 4.75 VBATT = 2.8V 4.70 4.65 MAX691A 4.60 MAX800L 4.55 4.50 4.45 4.40 MAX693A 4.35 MAX800M 4.30 -60 - 120 150 TEMPERATURE (°C) _______________________________________________________________________________________ BATTERY SUPPLY CURRENT vs. TEMPERATURE (BATTERY-BACKUP MODE VBATT = 2.8V NO LOAD 1 ...
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Microprocessor Supervisory Circuits ____________________________Typical Operating Characteristics (continued +25°C, unless otherwise noted.) A BATTERY CURRENT vs. INPUT SUPPLY VOLTAGE 20 VBATT = 2. OUT ...
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... and RESET Outputs The MAX691A/MAX693A/MAX800L/MAX800M’s RESET and RESET outputs ensure that the µP (with reset inputs asserted either high or low) powers known state, and prevents code-execution errors dur- ing power-down or brownout conditions. The RESET output is active low, and typically sinks 3.2mA at 0.1V saturation voltage in its active state. – ...
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... valid with V down to GND. CC RESET and RESET are asserted when V the reset threshold (4.65V for the MAX691A/MAX800L, 4.4V for the MAX693A/MAX800M) and remain asserted for 200ms typ after V rises above the reset threshold CC on power-up (Figure 5). The devices’ battery- switchover comparator does not affect reset assertion. ...
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... N.C. OSC IN Figure 3. Oscillator Circuits Chip-Enable Signal Gating The MAX691A/MAX693A/MAX800L/MAX800M provide internal gating of chip-enable (CE) signals to prevent erroneous data from being written to CMOS RAM in the event of a power failure. During normal operation, the CE gate is enabled and passes all CE transitions. When reset is asserted, this path becomes disabled, prevent- ing erroneous data from corrupting the CMOS RAM ...
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... VBATT MAX691A MAX693A MAX800L MAX800M 7 OSC IN 8 OSC SEL 11 WDI 9 PFI 1.25V * 4.4V FOR THE MAX693A/MAX800M Figure 4. MAX691A/MAX693A/MAX800L/MAX800M Block Diagram 5. RESET 4.0V THRESHOLD 5. OUT 0V 5V RESET 0V 5V RESET 0V LOGIC LEVELS SHOWN ARE FROM 0V TO 5V. Figure 5. Reset and Chip-Enable Timing ...
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... Both the switch and the diode have impedances less than 1Ω each. The maximum continuous current is 250mA, but power-on transients may reach a maximum of 1A. + VBATT MAX691A MAX693A MAX800L PFI LOW BATT PFO MAX800M GND ...
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... V cally be 200mV below V . Decouple this terminal with CC a 0.1µF capacitor. __________Applications Information The MAX691A/MAX693A/MAX800L/MAX800M are not short-circuit protected. Shorting V OUT than power-up transients such as charging a decou- pling capacitor, destroys the device. All open-circuit outputs swing between V rather than V and GND ...
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... Figure 12. Monitoring a Negative Voltage + C1* PFI MAX691A MAX693A R3 MAX800L MAX800M PFO GND TO P *OPTIONAL TRIP 1. 1. 1. PFO PFI MAX691A MAX693A MAX800L R2 MAX800M GND TRIP V- TRIP R2 IS NEGATIVE 13 ...
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Microprocessor Supervisory Circuits 100 +25°C A 0.1 F CAPACITOR 80 FROM 100 1000 RESET COMPARATOR OVERDRIVE, (Reset Threshold Voltage - V Figure 13. Maximum Transient Duration without Causing ...
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Microprocessor Supervisory Circuits Maximum V The V fall time is limited by the propagation delay of CC the battery switchover comparator and should not exceed 0.03V/µs. A standard rule of thumb for filter capacitance on most regulators is on the ...
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Microprocessor Supervisory Circuits _Ordering Information (continued) PART TEMP. RANGE MAX693ACPE 0°C to +70°C MAX693ACSE 0°C to +70°C MAX693ACWE 0°C to +70°C MAX693AC/D 0°C to +70°C MAX693AEPE -40°C to +85°C MAX693AESE -40°C to +85°C MAX693AEWE -40°C to +85°C MAX693AEJE -40°C to ...