3.3V EconoReset with Open Drain Output

FEATURES

►Automatically restarts a microprocessor after power failure

►Maintains reset for 150ms after VCC returns to an in-tolerance condition

►Reduces need for discrete components

►Precision temperature-compensated voltage reference and voltage sensor

► Accurate 5%, 10% or 20% power monitoring 20% tolerance for use with 3V systems

►Low-cost TO-92 or space saving SOT-23 packages available

►Efficient open-drain output with internal 5kpull-up resistor Operating temperature -40C to +85C P

DESCRIPTION

The DS1816 EconoReset uses a precision temperature reference and comparator circuit to monitor the status of the power supply (VCC). When an out-of-tolerance condition is detected, an internal power-fail signal is generated which forces reset to the active state. When VCC returns to an in-tolerance condition, the reset signal is kept in the active state for approximately 150ms to allow the power supply and processor to stabilize.

OPERATION — POWER MONITOR

The DS1816 provides the function of detecting out-of-tolerance power supply conditions and warning a processor-based system of impending power failure. When VCC is detected as out-of-tolerance, the RST signal is asserted. On power-up, RST is kept active for approximately 150ms after the power supply has reached the selected tolerance. This allows the power supply and microprocessor to stabilize before RST is released.

ABSOLUTE MAXIMUM RATINGS*

Voltage on VCC Pin Relative to Ground -0.5V to +7.0V

Voltage on RST Relative to Ground -0.5V to VCC + 0.5V

Operating Temperature Range -40°C to +85°C

Storage Temperature Range -55°C to +125°C

Soldering Temperature 260°C for 10 seconds

* This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability

BLOCK DIAGRAM (OPEN-DRAIN OUTPUT) Figure 1