DS1833 5V EconoReset www.maxim-ic.com FEATURES § § § § § § § § PIN ASSIGNMENT Automatically restarts microprocessor after power failure Maintains active-high reset for 350 ms after VCC returns to an in-tolerance condition Accurate 5%, 10% or 15% microprocessor 5V power supply monitoring Reduces need for discrete components Precision temperature-compensated voltage reference and voltage sensor Low-cost TO-92 package or surface mount SOT-223 package Internal 5k pull-up resistor Operating temperature of -40°C to +85°C 1 DALLAS DS1833 Econo Reset 2 4 3 TOP VIEW SOT-23 PACKAGE See Mech. Drawings Section On Website 1 2 3 1 2 3 BOTTOM VIEW TO-92 PACKAGE See Mech. Drawings Section On Website PIN DESCRIPTION PIN 1 PIN 2 PIN 3 PIN 4 Ground Reset VCC Ground (SOT-223 only) DESCRIPTION The DS1833 EconoReset uses a precision temperature compensated 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 (high) state. When VCC returns to an intolerance condition, the reset signal is kept in the active state for approximately 350 ms to allow the power supply and processor to stabilize. OPERATION - POWER MONITOR The DS1833 provides the functions 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, as defined by the tolerance of the part selected, the RST signal is asserted. On power-up, RST is kept active for approximately 350 ms after the power supply has reached the selected tolerance. This allows the power supply and microprocessor to stabilize before RST is released. 1 of 5 041002 DS1833 BLOCK DIAGRAM Figure 1 APPLICATION EXAMPLE Figure 2 2 of 5 DS1833 POWER-UP Figure 3 POWER-DOWN Figure 4 3 of 5 DS1833 ABSOLUTE MAXIMUM RATINGS* Voltage on VCC Pin Relative to Ground Voltage on I/O Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * -0.5V to +7.0V -0.5V to VCC +0.5V -40°C to +85°C -55°C to +125°C 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. RECOMMENDED DC OPERATING CONDITIONS (-40°C to +85°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Supply Voltage VCC 1.2 5.0 5.5 V 1 (-40°C to +85°C; VDD=5V ± 10%) DC ELECTRICAL CHARACTERISTICS PARAMETER Low Level @ RST SYMBOL VOL MIN Output Current @ 0.4V IOL +8 Operating Current ICC VCC Trip Point 5% VCCTP1 VCC Trip Point 10% TYP MAX 0.4 UNITS V NOTES 1 mA 1.5 2 mA 4.5 4.625 4.74 V 1 VCCTP2 4.25 4.375 4.49 V 1 VCC Trip Point 15% VCCTP3 4.0 4.125 4.24 V 1 Output Capacitance COUT 10 pF 6.25 kW Internal Pull-Up Resistor RP 3.75 (-40°C to +85°C; VCC=5V ± 10%) AC ELECTRICAL CHARACTERISTICS PARAMETER Reset Active Time SYMBOL tRST VCC Detect to RST tRPD 5 MIN 250 TYP 350 MAX 450 UNITS ms 100 ns VCC Slew Rate (4.75V - 4.00V) tF 300 ms VCC Slew Rate (4.00V - 4.75V) tR 0 ns tRPU 250 VCC Detect to RST NOTES: 1. All voltages are referenced to ground. 4 of 5 350 450 ms NOTES DS1833 ECONORESET SELECTION GUIDE VCC TRIP POINT 5V 3.3V PUSHBUTTON DETECT MIN TYP MAX MIN TYP MAX DS1233-15 4.0 4.125 4.24 2.4 - 3.3 DS1233-10 4.25 4.375 4.49 2.4 - 3.3 DS1233-5 4.5 4.625 4.75 2.4 - 3.3 DS1233D-15 4.0 4.125 4.24 N/A N/A DS1233D-10 4.25 4.375 4.49 N/A N/A DS1233D-5 4.5 4.625 4.75 N/A N/A DS1833-15 4.0 4.125 4.24 N/A N/A DS1833-10 4.25 4.375 4.49 N/A N/A DS1833-5 4.5 4.625 4.75 N/A N/A DS1233A-15 2.64 2.72 2.80 1.8 - 3.0 DS1233A-10 2.8 2.88 2.97 1.8 - 3.0 5 of 5