DS1233M-3

DS1233M 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 Reduces need for discrete components Precision temperature-compensated voltage reference and voltage sensor Low-cost TO-92 package or surface mount 8-pin SOIC packages available Internal 5 kW pullup resistor Compatible with Motorola 68XXX series and HC16 Microprocessors Pin function compatible with the Motorola MC33064, MC34064, MC33164, and MC34164 Operating temperature of -40°C to +85°C DALLAS DS1233 Econo Reset RST 1 8 NC VCC 2 7 NC NC 3 6 NC GND 4 5 NC DS1233M 8-Pin SOIC (150mil) See Mech. Drawings Section on Website 1 2 3 _ 1 _ 2 _ 3 BOTTOM VIEW TO-92 PACKAGE See Mech. Drawings Section On Website PIN DESCRIPTIONS TO-92 1 RST 2 VCC 3 GND - Active Low Reset Output - Power Supply - Ground 8-Pin SOIC RST VCC NC GND - Active Low Reset Output - Power Supply - No Connect - Ground DESCRIPTION The DS1233M 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 (low) 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. 1 of 4 041002 DS1233M OPERATION - POWER MONITOR The DS1233M 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. BLOCK DIAGRAM Figure 1 APPLICATION EXAMPLE Figure 2 2 of 4 DS1233M TIMING DIAGRAM: POWER-UP Figure 3 VOLTAGE TRIP LEVELS PARAMETER Voltage High Trip Level Voltage Low Trip Level Voltage High Trip Level Voltage Low Trip Level SYMBOL MIN TYP MAX UNITS VHTL 4.75 V VLTL 4.00 V VHTL VLTL 3.14 2.48 V V TIMING DIAGRAM: POWER-DOWN Figure 4 3 of 4 NOTES DS1233M-5, DS1233M-55 DS1233M-5, DS1233M-55 DS1233M-3 DS1233M-3 DS1233M 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 PARAMETER Supply Voltage SYMBOL VCC MIN 1.2 DC ELECTRICAL CHARACTERISTICS PARAMETER Output Voltage @ -500 mA Output Current @ 0.4V Operating Current VCC Trip Point (DS1233M-5) VCC Trip Point (DS1233M-55) VCC Trip Point (DS1233M-3) Output Capacitance Internal Pullup Resistor PARAMETER Reset Active Time VCC Detect to RST VCC Slew Rate (VHTL - VLTL ) VCC Slew Rate (VLTL - VHTL ) VCC Detect to RST TYP SYMBOL MIN tRST 200 tRPD tF 300 tR 0 tRPU 200 MAX 5.5 UNITS V NOTES 1 (-40°C to +85°C; VCC = 1.2V to 5.5V) SYMBOL MIN VCC-0.5V VOH IOL +8 ICC VCCTP 4.25 VCCTP 4.5 VCCTP 2.64 COUT RP 3.75 AC ELECTRICAL CHARACTERISTICS (-40°C to +85°C) TYP MAX VCC-0.1V 4.375 4.625 2.72 5 50 4.49 4.75 2.8 10 6.50 UNITS V mA mA V V V pF kW (-40°C to +85°C; VCC = 1.2V to 5.5V) TYP 350 2 MAX 500 10 350 500 UNITS ms ms ms ns ms NOTES: 1. All voltages are referenced to ground. 2. Measured with VCC ³ 2.7V. 3. A 1 kW external resistor may be required in some applications for proper operation of the microprocessor reset control circuit. 4. Measured with outputs open. 5. tR = 5 ms. 4 of 4 NOTES 1 2,3 4 1 1 1 NOTES 5