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MAX791
Microprocessor Supervisory Circuit
Full-Function µP Supervisory Circuit
MyMaxim SubscriptionsProduct Details
Key Features
Applications/Uses
Parametric specs for Battery Backup Circuits
| Reset Thresh. (V) | 3.3 to 5.5 |
| Reset Out | Active Low Push-Pull |
| ICC (µA) (max) | 150 |
| Oper. Temp. (°C) | -55 to +125 -40 to +85 0 to +70 |
| Package/Pins | CDIP/16 PDIP/16 SOIC (N)/16 |
| Budgetary Price (See Notes) | 5.86 |
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Simplified Block Diagram
Technical Docs
| Data Sheet | Microprocessor Supervisory Circuit | Mar 14, 2006 | |
| App Note | Provide Battery Backup For Pseudo-Static RAMs |
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
Parameters
Parametric specs for Battery Backup Circuits
| Reset Thresh. (V) | 3.3 to 5.5 |
| Reset Out | Active Low Push-Pull |
| ICC (µA) (max) | 150 |
| Oper. Temp. (°C) | -55 to +125 -40 to +85 0 to +70 |
| Package/Pins | CDIP/16 PDIP/16 SOIC (N)/16 |
| Budgetary Price (See Notes) | 5.86 |
Key Features
- Precision 4.65V Voltage Monitoring
- 200ms Power-OK/Reset Time Delay
- Independent Watchdog Timer-Preset or Adjustable
- 1µA Standby Current
- Power Switching
- 250mA Output in VCC Mode
- 25mA Output in Battery-Backup Mode
- On-Board Gating of Chip-Enable Signals
- Memory Write-Cycle Completion
- 6ns CE Gate Propagation Delay
- MaxCap™ or SuperCap™ Compatible
- Voltage Monitor for Power-Fail or Low-Battery Warning
- Backup-Battery Monitor
- Guaranteed RESET-bar Valid to VCC = 1V
Applications/Uses
- Computers: Desktop, Workstation, Server
- Controllers
- Critical µP Monitoring
- Intelligent Instruments
- Portable Battery-Powered Equipment
Description
The MAX791 microprocessor (µP) supervisory circuit reduces the complexity and number of components needed to monitor power-supply and battery-control functions in µP systems. The 50µA supply current makes the MAX791 ideal for use in portable equipment, while the 6ns chip-enable propagation delay and 250mA output capability (25mA in battery-backup mode) make it suitable for larger, higher-performance equipment.
The MAX791 comes in 16-pin DIP and narrow SO packages and provides the following functions:
The MAX791 comes in 16-pin DIP and narrow SO packages and provides the following functions:
- µP reset-RESET-bar output is asserted during power-up, power-down, and brownout conditions, and is guaranteed to be in the correct state for VCC down to 1V, even with no battery in the circuit.
- Manual-reset input.
- A 1.25V threshold detector provides for power-fail warning and low-battery detection, or monitors a power supply other than +5V.
- Two-stage power-fail warning-a separate low-line comparator compares VCC to a threshold 150mV above the reset threshold.
- Backup-battery switchover for CMOS RAM, real-time clocks, µPs, or other low-power logic.
- Software monitoring of backup-battery voltage.
- A watchdog-fault output is asserted if the watchdog input has not been toggled within either a preset or an adjustable timeout period.
- Write protection of CMOS RAM or EEPROM.
- Pulsed watchdog output, to give advance warning of impending WDO-bar assertion caused by watchdog timeout.
Technical Docs
| Data Sheet | Microprocessor Supervisory Circuit | Mar 14, 2006 | |
| App Note | Provide Battery Backup For Pseudo-Static RAMs |
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
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