19-0344; Rev 4; 12/99 3-Pin Microprocessor Reset Circuits These circuits perform a single function: they assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. Reset thresholds suitable for operation with a variety of supply voltages are available. The MAX803 has an open-drain output stage, while the MAX809/MAX810 have push-pull outputs. The MAX803’s open-drain RESET output requires a pull-up resistor that can be connected to a voltage higher than VCC. The MAX803/MAX809 have an active-low RESET output, while the MAX810 has an active-high RESET output. The reset comparator is designed to ignore fast transients on VCC, and the outputs are guaranteed to be in the correct logic state for VCC down to 1V. Low supply current makes the MAX803/MAX809/ MAX810 ideal for use in portable equipment. The MAX803 is available in a 3-pin SC70 package, and the MAX809/MAX810 are available in 3-pin SC70 or SOT23 packages. Applications Computers Controllers Intelligent Instruments Critical µP and µC Power Monitoring Portable/Battery-Powered Equipment Automotive ____________________________Features ♦ Precision Monitoring of +2.5V, +3V, +3.3V, and +5V Power-Supply Voltages ♦ Fully Specified Over Temperature ♦ Available in Three Output Configurations Open-Drain RESET Output (MAX803) Push-Pull RESET Output (MAX809) Push-Pull RESET Output (MAX810) ♦ 140ms min Power-On Reset Pulse Width ♦ 12µA Supply Current ♦ Guaranteed Reset Valid to VCC = +1V ♦ Power Supply Transient Immunity ♦ No External Components ♦ 3-Pin SC70 and SOT23 Packages Ordering Information PART TEMP. RANGE PIN-PACKAGE MAX803_EXR-T MAX803_EXR-T10 MAX809_EXR-T MAX809_EXR-T10 MAX809_EUR-T MAX809_EUR-T10 MAX810_EXR-T MAX810_EXR-T10 MAX810_EUR-T MAX810_EUR-T10 -40°C to +105°C -40°C to +105°C -40°C to +105°C -40°C to +105°C -40°C to +105°C -40°C to +105°C -40°C to +105°C -40°C to +105°C -40°C to +105°C -40°C to +105°C 3 SC70-3 3 SC70-3 3 SC70-3 3 SC70-3 3 SOT23-3 3 SOT23-3 3 SC70-3 3 SC70-3 3 SOT23-3 3 SOT23-3 Note: These parts are offered in 2.5k or 10k reels, and must be ordered in 2.5k or 10k increments. Order MAX803_EXR-T for 2.5k reels and MAX803_EXR-T10 for 10k reels. Insert the desired suffix letter from the Selector Guide into the blank to complete the part number. All versions of these products may not be available at the time of announcement. Contact factory for availability. Pin Configuration Typical Operating Circuit TOP VIEW VCC GND 1 VCC VCC RPULL-UP* RESET MAX803 MAX809 MAX810 µP MAX803 MAX809 RESET INPUT 3 VCC RESET (RESET) 2 GND GND SC70-3/SOT23-3 *MAX803 ONLY ( ) ARE FOR MAX810. MAX803 AVAILABLE IN SC70-3 ONLY. ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z General Description The MAX803/MAX809/MAX810 are microprocessor (µP) supervisory circuits used to monitor the power supplies in µP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V, +3.3V, +3.0V, or +2.5V-powered circuits. MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z 3-Pin Microprocessor Reset Circuits ABSOLUTE MAXIMUM RATINGS Continuous Power Dissipation (TA = +70°C) 3-Pin SC70 (derate 2.17mW/°C above +70°C) ............174mW 3-Pin SOT23 (derate 4mW/°C above +70°C)...............320mW Operating Temperature Range .........................-40°C to +105°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Terminal Voltage (with respect to GND) VCC ....................................................................-0.3V to +6.0V RESET, RESET (push-pull) .....................-0.3V to (VCC + 0.3V) RESET (open drain)...........................................-0.3V to +6.0V Input Current, VCC ..............................................................20mA Output Current, RESET, RESET ..........................................20mA Rate of Rise, VCC ............................................................100V/µs Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VCC = full range, TA = -40°C to +105°C, unless otherwise noted. Typical values are at TA = +25°C, VCC = 5V for L/M/J versions, VCC = 3.3V for T/S versions, VCC = 3V for R version, and VCC = 2.5V for Z version.) (Note 1) PARAMETER SYMBOL VCC Range Supply Current (SOT23) Supply Current (SC70) ICC ICC CONDITIONS TA = -40°C to +105°C 1.2 5.5 TA = -40°C to +85°C VCC < 5.5V, MAX8_ _J/L/M 24 60 VCC < 3.6V, MAX8_ _R/S/T 17 50 TA = +85°C to +105°C VCC < 5.5V, MAX8_ _L/M 100 VCC < 3.6V, MAX8_ _R/S/T 100 TA = -40°C to +85°C VCC < 5.5V, MAX8_ _L/M 16 35 VCC < 3.6V, MAX8_ _R/S/T/Z 12 30 TA = +85°C to +105°C VCC < 5.5V, MAX8_ _L/M MAX809J (SOT only) MAX8_ _T MAX8_ _S MAX8_ _R MAX8_ _Z (SC70 only) 2 MAX 5.5 MAX8_ _M VTH TYP 1.0 MAX8_ _L Reset Threshold MIN TA = 0°C to +70°C UNITS V µA 75 VCC < 3.6V, MAX8_ _R/S/T/Z 75 TA = +25°C 4.56 4.63 4.70 TA = -40°C to +85°C 4.50 TA = +85°C to +105°C 4.40 TA = +25°C 4.31 TA = -40°C to +85°C 4.25 TA = +85°C to +105°C 4.16 TA = +25°C 3.93 TA = -40°C to +85°C 3.89 TA = +85°C to +105°C 3.80 TA = +25°C 3.04 TA = -40°C to +85°C 3.00 3.15 TA = +85°C to +105°C 2.92 3.23 TA = +25°C 2.89 TA = -40°C to +85°C 2.85 TA = +85°C to +105°C 2.78 TA = +25°C 2.59 TA = -40°C to +85°C 2.55 TA = +85°C to +105°C 2.50 TA = +25°C 2.28 TA = -40°C to +85°C 2.25 2.38 TA = +85°C to +105°C 2.21 2.45 4.75 4.86 4.38 4.45 4.50 4.56 4.00 4.06 4.10 4.20 3.08 2.93 3.11 2.96 3.00 3.08 2.63 2.66 2.70 2.76 2.32 _______________________________________________________________________________________ 2.35 V 3-Pin Microprocessor Reset Circuits (VCC = full range, TA = -40°C to +105°C, unless otherwise noted. Typical values are at TA = +25°C, VCC = 5V for L/M/J versions, VCC = 3.3V for T/S versions, VCC = 3V for R version, and VCC = 2.5V for Z version.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP Reset Threshold Tempco MAX 30 VCC to Reset Delay (Note 2) VCC = VTH to (VTH - 100mV) Reset Active Timeout Period (SOT23) TA = -40°C to +85°C 140 TA = +85°C to +105°C 100 Reset Active Timeout Period (SC70) TA = -40°C to +85°C 140 TA = +85°C to +105°C 100 RESET Output Voltage Low (push-pull active low and opendrain active-low, MAX803 and MAX809) VOL RESET Output Voltage High (push-pull active low, MAX809) VOH RESET Output Voltage Low (push-pull active high, MAX810) VOL RESET Output Voltage High (push-pull active high, MAX810) VOH RESET Open-Drain Output Leakage Current (MAX803) 20 µs 240 560 840 240 460 840 VCC = VTH min, ISINK = 1.2mA, MAX803R/S/T/Z, MAX809R/S/T/Z 0.3 VCC = VTH min, ISINK = 3.2mA, MAX803L/M, MAX809J/L/M 0.4 VCC > 1.0V, ISINK = 50µA 0.3 VCC > VTH max, ISOURCE = 500µA, MAX809R/S/T/Z 0.8VCC VCC > VTH max, ISOURCE = 800µA, MAX809J/L/M VCC - 1.5 UNITS ppm/°C ms ms V V VCC = VTH max, ISINK = 1.2mA, MAX810R/S/T/Z 0.3 VCC = VTH max, ISINK = 3.2mA, MAX810L/M 0.4 V 1.8V < VCC < VTH min, ISOURCE = 150µA 0.8VCC V VCC > VTH, RESET deasserted 1 µA Note 1: Production testing done at TA = +25°C; limits over temperature guaranteed by design only. Note 2: RESET output for MAX803/MAX809; RESET output for MAX810. Typical Operating Characteristics (VCC = full range, TA = -40°C to +105°C, unless otherwise noted. Typical values are at TA = +25°C, VCC = +5V for L/M/J versions, VCC = +3.3V for T/S versions, VCC = +3V for R version, and VCC = +2.5V for Z version.) SUPPLY CURRENT vs. TEMPERATURE (SC70 PACKAGE, NO LOAD) SUPPLY CURRENT (µA) MAX8_ _L/M, VCC = 5V MAX8_ _R/S/T, VCC = 3.3V 10 MAX8_ _Z, VCC = 2.5V 5 VOD = VTH - VCC 80 MAX803-TOC3 100 POWER-DOWN RESET DELAY (µs) MAX803 toc01 15 POWER-DOWN RESET DELAY vs. TEMPERATURE (MAX8_ _R/S/T/Z) VOD = 10mV 60 VOD = 20mV 40 VOD = 100mV 20 MAX8_ _L/M/R/S/T/Z, VCC = 1V VOD = 200mV 0 0 -40 -20 0 20 40 TEMPERATURE (°C) 60 85 -40 -20 20 0 40 TEMPERATURE (°C) 60 85 _______________________________________________________________________________________ 40 3 MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (VCC = full range, TA = -40°C to +105°C, unless otherwise noted. Typical values are at TA = +25°C, VCC = +5V for L/M/J versions, VCC = +3.3V for T/S versions, VCC = +3V for R version, and VCC = +2.5V for Z version.) POWER-UP RESET TIMEOUT vs. TEMPERATURE 100 VOD = 20mV 80 60 40 VOD = 100mV 20 VOD = 200mV 0 -40 -20 20 0 40 TEMPERATURE (°C) 60 1.002 245 MAX8_ _J/L/M 240 MAX8_ _R/S/T/Z 235 230 1.001 1.000 0.999 0.998 225 85 1.003 MAX803-TOC6 VOD = 10mV 250 MAX803-TOC5 120 NORMALIZED RESET THRESHOLD vs. TEMPERATURE NORMALIZED THRESHOLD VOD = VTH - VCC POWER-UP RESET TIMEOUT (ms) 140 MAX803-TOC4 POWER-DOWN RESET DELAY vs. TEMPERATURE (MAX8_ _J/L/M) POWER-DOWN RESET DELAY (µs) MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z 3-Pin Microprocessor Reset Circuits 0.997 -40 -20 0 20 40 60 85 -40 TEMPERATURE (°C) -20 0 20 40 60 85 TEMPERATURE (°C) Selector Guide 4 TOP MARK PART/SUFFIX RESET THRESHOLD (V) OUTPUT TYPE MAX803L 4.63 Open-Drain RESET — AAZ MAX803M 4.38 Open-Drain RESET — ABA MAX803T 3.08 Open-Drain RESET — ABB MAX803S 2.93 Open-Drain RESET — ABC MAX803R 2.63 Open-Drain RESET — ABD MAX803Z 2.32 Open-Drain RESET — ABE MAX809L 4.63 Push-Pull RESET AAAA AAN MAX809M 4.38 Push-Pull RESET ABAA AAO SOT SC70 MAX809J 4.00 Push-Pull RESET CWAA — MAX809T 3.08 Push-Pull RESET ACAA AAP MAX809S 2.93 Push-Pull RESET ADAA AAQ MAX809R 2.63 Push-Pull RESET AFAA AAR MAX809Z 2.32 Push-Pull RESET — AAS MAX810L 4.63 Push-Pull RESET AGAA AAT MAX810M 4.38 Push-Pull RESET AHAA AAU AAV MAX810T 3.08 Push-Pull RESET AJAA MAX810S 2.93 Push-Pull RESET AKAA AAX MAX810R 2.63 Push-Pull RESET ALAA AAW MAX810Z 2.32 Push-Pull RESET — AAY _______________________________________________________________________________________ 3-Pin Microprocessor Reset Circuits PIN NAME 1 GND FUNCTION VCC Ground RESET (MAX803/ MAX809) RESET Output remains low while VCC is below the reset threshold, and for at least 140ms after VCC rises above the reset threshold. RESET (MAX810) RESET Output remains high while VCC is below the reset threshold, and for at least 140ms after VCC rises above the reset threshold. VCC Supply Voltage (+5V, +3.3V, +3.0V, or +2.5V) 2 3 MAX809 RESET GND R1 100k Figure 2. RESET Valid to VCC = Ground Circuit Applications Information MAXIMUM TRANSIENT DURATION (µs) 400 Negative-Going VCC Transients TA = +25°C 320 240 160 MAX8_ _J/L/M 80 MAX8_ _R/S/T/Z 0 1 10 100 1000 RESET COMPARATOR OVERDRIVE, VTH - VCC (mV) Figure 1. Maximum Transient Duration Without Causing a Reset Pulse vs. Reset Comparator Overdrive Detailed Description A microprocessor’s (µP’s) reset input starts the µP in a known state. The MAX803/MAX809/MAX810 assert reset to prevent code-execution errors during powerup, power-down, or brownout conditions. They assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. The MAX803 uses an open-drain output, and the MAX809/MAX810 have a push-pull output stage. Connect a pull-up resistor on the MAX803’s RESET output to any supply between 0 and 6V. In addition to issuing a reset to the µP during power-up, power-down, and brownout conditions, the MAX803/ MAX809/MAX810 are relatively immune to short-duration negative-going VCC transients (glitches). Figure 1 shows typical transient duration vs. reset comparator overdrive, for which the MAX803/MAX809/ MAX810 do not generate a reset pulse. The graph was generated using a negative-going pulse applied to VCC, starting 0.5V above the actual reset threshold and ending below it by the magnitude indicated (reset comparator overdrive). The graph indicates the maximum pulse width a negative-going VCC transient can have without causing a reset pulse. As the magnitude of the transient increases (goes farther below the reset threshold), the maximum allowable pulse width decreases. Typically, for the MAX8__L and MAX8__M, a VCC transient that goes 100mV below the reset threshold and lasts 20µs or less will not cause a reset pulse. A 0.1µF bypass capacitor mounted as close as possible to the VCC pin provides additional transient immunity. Ensuring a Valid Reset Output Down to VCC = 0 When VCC falls below 1V, the MAX809 RESET output no longer sinks current—it becomes an open circuit. Therefore, high-impedance CMOS logic inputs connected to RESET can drift to undetermined voltages. This presents no problem in most applications since most µP and other circuitry is inoperative with V CC below 1V. However, in applications where RESET must be valid down to 0V, adding a pull-down resistor to RESET causes any stray leakage currents to flow to _______________________________________________________________________________________ 5 MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z _____________________Pin Description MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z 3-Pin Microprocessor Reset Circuits +5.0V +3.3V VCC VCC VCC RPULLUP µP MAX803 RESET GND VCC VCC MOTOROLA RESET 68HCXX INPUT GND Figure 3. Interfacing to µPs with Bidirectional Reset I/O ground, holding RESET low (Figure 2). R1’s value is not critical; 100kΩ is large enough not to load RESET and small enough to pull RESET to ground. A 100kΩ pull-up resistor to VCC is also recommended for the MAX810 if RESET is required to remain valid for VCC < 1V. Interfacing to µPs with Bidirectional Reset Pins Since the RESET output on the MAX803 is open drain, this device interfaces easily with µPs that have bidirectional reset pins, such as the Motorola 68HC11. Connecting the µP supervisor’s RESET output directly to the microcontroller’s (µC’s) RESET pin with a single pull-up resistor allows either device to assert reset (Figure 3). 5V SYSTEM MAX803 RESET RESET INPUT GND GND Figure 4. MAX803 Open-Drain RESET Output Allows Use with Multiple Supplies Benefits of Highly Accurate Reset Threshold Most µP supervisor ICs have reset threshold voltages between 5% and 10% below the value of nominal supply voltages. This ensures a reset will not occur within 5% of the nominal supply, but will occur when the supply is 10% below nominal. When using ICs rated at only the nominal supply ±5%, this leaves a zone of uncertainty where the supply is between 5% and 10% low, and where the reset may or may not be asserted. The MAX8_ _L/T/Z use highly accurate circuitry to ensure that reset is asserted close to the 5% limit, and long before the supply has declined to 10% below nominal. MAX803 Open-Drain RESET Output Allows Use with Multiple Supplies Generally, the pull-up connected to the MAX803 will connect to the supply voltage that is being monitored at the IC’s VCC pin. However, some systems may use the open-drain output to level-shift from the monitored supply to reset circuitry powered by some other supply (Figure 4). Note that as the MAX803’s VCC decreases below 1V, so does the IC’s ability to sink current at RESET. Also, with any pull-up, RESET will be pulled high as VCC decays toward 0. The voltage where this occurs depends on the pull-up resistor value and the voltage to which it is connected. 6 ___________________Chip Information TRANSISTOR COUNT: 275 (SOT23) 380 (SC70) _______________________________________________________________________________________ 3-Pin Microprocessor Reset Circuits SC70, 3L.EPS _______________________________________________________________________________________ 7 MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z Package Information Package Information (continued) SOTPO3L.EPS MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z 3-Pin Microprocessor Reset Circuits Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.