LTC695ISW-3.3 microprocessor monitoring circuit
peculiarity
- 保证复位确定在 VCC = 1V
- 1.5mA 最大电源电流
- RAM 芯片使能信号的快速 (最大 35ns) 板上选通
- SO-8 和 S16 封装
- 4.65V 精准电压监视器
- 电源运行正常/复位延时：50ms、200ms 或可调
- 最少的外部元件数目
- 1μA 最大待机电流
- 用于电源故障或低电池电量报警的电压监视器
- 热限制
- 规定了整个温度范围内的性能
- MAX690 系列的卓越升级产品
The LTC®690 series provides full power monitoring and battery control functions for microprocessor reset, battery backup, CMOS RAM write protection, power failure alarm, and watchdog timing. A precise internal voltage reference and comparator circuit monitors the power lines. When the tolerance range is exceeded, the reset output will be forced into an operating state, and the chip enable output will unconditionally write protect the external memory. In addition, the RESET output will be guaranteed to be logically low, even when VCC is as low as 1V.
The LTC690 series utilizes a charge pump NMOS power switch to power active CMOS RAM and is designed for low dropout and low supply current. When the main power supply is lost, the secondary power supply (connected to the battery input pin) will power the RAM in standby state via a high-efficiency PMOS switch.
To provide early warning when a power failure is imminent, the LTC690 Series offers an internal comparator with user-defined thresholds. In addition, an internal watchdog timer is provided that will force the reset pin to enter the running state when the watchdog input is not transformed before a preset timeout period.