DS1233DZ-15

DS1233D 5V EconoReset www.maxim-ic.com FEATURES § § § § § § § § § PIN ASSIGNMENT Automatically restarts microprocessor after power failure Maintains 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 5 kW pull-up resistor Compatible with Motorola 68XXX series and HC16 Microprocessors Operating temperature of -40°C to +85°C 1 DALLAS DS1233 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 DS1233D 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 state. When VCC returns to an in-tolerance 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 DS1233D 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 DS1233D BLOCK DIAGRAM Figure 1 APPLICATION EXAMPLE Figure 2 2 of 5 DS1233D POWER UP Figure 3 POWER DOWN Figure 4 3 of 5 DS1233D 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 SYMBOL VOL MIN Output Current @ 0.4V IOL +8 Operating Current ICC VCC Trip Point 5% VCCTP1 4.5 VCC Trip Point 10% VCCTP2 VCC Trip Point 15% VCCTP3 Output Capacitance COUT Low Level @ RST Internal Pull-Up Resistor RP SYMBOL tRST VCC Detect to RST tRPD MAX 0.4 UNITS V NOTES 1 mA 2 50 mA 4.625 4.74 V 1 4.25 4.375 4.49 V 1 4.0 4.125 4.24 V 1 10 pF 6.25 kW 3.75 5 (-40°C to +85°C; VCC=5V ± 10%) AC ELECTRICAL CHARACTERISTICS PARAMETER Reset Active Time TYP 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 350 450 NOTES ms NOTES: 1. All voltages are referenced to ground. 2. A 1 kW external resistor may be required for proper operation of the microprocessor reset control circuit. 4 of 5 DS1233D 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