概述
The MAX807 microprocessor (µP) supervisory circuit reduces the complexity and number of components needed to monitor power-supply and battery-control functions in µP systems. A 70µA supply current makes the MAX807 ideal for use in portable equipment, while a 2ns chip-enable propagation delay and 250mA output current capability (20mA in battery-backup mode) make it suitable for larger, higher-performance equipment.
The MAX807 comes in 16-pin DIP, SO, and TSSOP packages, and provides the following functions:
µP reset. The active-low 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.
Active-high RESET output.
Manual-reset input.
Two-stage power-fail warning. A separate low-line comparator compares VCC to a threshold 52mV above the reset threshold. This low-line comparator is more accurate than those in previous µP supervisors.
Backup-battery switchover for CMOS RAM, real-time clocks, µPs, or other low-power logic.
Write protection of CMOS RAM or EEPROM.
2.275V threshold detector provides for power-fail warning and low-battery detection, or monitors a power supply other than +5V.
BATT OK status flag indicates that the backup-battery voltage is above +2.275V.
Watchdog-fault output—asserted if the watchdog input has not been toggled within a preset timeout period.
| 关键特性 |
|
应用 |
- Precision 4.675V (MAX807L), 4.425V (MAX807M), or 4.575V (MAX807N) Voltage Monitoring
- 200ms Power-OK/Reset Time Delay
- RESET-bar and RESET Outputs
- Independent Watchdog Timer
- 1µA Standby Current
- Power Switching
- 250mA in VCC Mode
- 20mA in Battery-Backup Mode
- On-Board Gating of Chip-Enable Signals;
- 2ns CE Gate Propagation Delay
- MaxCap® and SuperCap Compatible
- Voltage Monitor for Power Fail
- Backup-Battery Monitor
- Guaranteed RESET-bar Valid to VCC = 1V
- ±1.5% Low-Line Threshold Accuracy 52mV above Reset Threshold
|
| 图表 |
 | |
|
|
