DS1815R-20+T&R Analog Devices

DS1815 3.3V EconoReset with Push-Pull Output www.maxim-ic.com FEATURES PIN ASSIGNMENT Automatically restarts a microprocessor after 3 power failure DALLAS DS1815 Maintains reset for 150ms after V returns to CC Econo Reset an in-tolerance condition Reduces need for discrete components Precision temperature-compensated voltage 12 reference and voltage sensor TOP VIEW SOT-23 PACKAGE Accurate 5%, 10% or 20% power monitoring See Mech. Drawings Section Low-cost TO-92 or space saving surface- On Website 1 2 3 mount SOT-23 packages available Push-pull output for low current operation 1 2 3 Operating temperature -40 C to +85 C BOTTOM VIEW TO-92 PACKAGE See Mech. Drawings Section On Website PIN DESCRIPTION TO-92 1 RST Active Low Reset Output 2 V Power Supply CC 3 GND Ground SOT-23 1 RST Active Low Reset Output 2 V Power Supply CC 3 GND Ground DESCRIPTION The DS1815 EconoReset uses a precision temperature reference and comparator circuit to monitor the status of the power supply (V ). When an out-of-tolerance condition is detected, an internal power-fail CC signal is generated which forces reset to the active state. When V returns to an in-tolerance condition, CC the reset signal is kept in the active state for approximately 150ms to allow the power supply and processor to stabilize. 1 of 5 041002DS1815 OPERATION POWER MONITOR The DS1815 provides the functions of detecting out-of-tolerance power supply conditions and warning a processor-based system of impending power failure. When V is detected as out of tolerance, the RST CC 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. BLOCK DIAGRAM (CMOS OUTPUT) Figure 1 APPLICATION EXAMPLE Figure 2 APPLICATION DIAGRAM: RST VALID TO 0 VOLTS V ON THE DS1815 Figure 3 CC 2 of 5