19-0344; Rev 7; 2/10 3-Pin Microprocessor Reset Circuits 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. 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 pullup 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 -40°C to +125°C 3 SC70 MAX803_EXR+T -40°C to +125°C 3 SC70 MAX809_EXR-T -40°C to +125°C 3 SC70 MAX809_EXR+T -40°C to +125°C 3 SC70 MAX809_EUR-T -40°C to +105°C 3 SOT23 MAX809_EUR+T -40°C to +105°C 3 SOT23 MAX810_EXR-T -40°C to +125°C 3 SC70 MAX810_EXR+T -40°C to +125°C 3 SC70 MAX810_EUR-T -40°C to +105°C 3 SOT23 MAX810_EUR+T -40°C to +105°C 3 SOT23 Note: These parts are offered in 2.5k reels, and must be ordered in 2.5k increments. 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. Devices are available in both leaded and lead-free packaging. +Denotes a lead(Pb)-free/RoHS-compliant package. Typical Operating Circuit Pin Configuration TOP VIEW VCC VCC VCC GND 1 RPULLUP* μP MAX803 MAX809 RESET GND MAX803 MAX809 MAX810 RESET INPUT GND 3 VCC RESET (RESET) 2 SC70-3/SOT23-3 *MAX803 ONLY ( ) ARE FOR MAX810. MAX803 AVAILABLE IN SC70-3 ONLY. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z General 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 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 3-Pin SC70 .....................................................-40°C to +125°C 3-Pin SOT23...................................................-40°C to +105°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Soldering Temperature (reflow) .......................................+260°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 (SOT23) or TA = -40°C to +125°C (SC70), 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) ICC CONDITIONS ICC TA = -40°C to +105°C (MAX8_ _ _EUR) 1.2 5.5 TA = -40°C to +125°C (MAX8_ _ _EXR) 1.2 VCC < 5.5V, MAX8_ _L/M 24 60 VCC < 3.6V, MAX8_ _R/S/T/Z 17 50 TA = +85°C to +105°C VCC < 5.5V, MAX8_ _L/M 100 VCC < 3.6V, MAX8_ _R/S/T/Z 100 TA = +85°C to +125°C MAX809J (SOT only) VTH MAX8_ _T MAX8_ _S MAX8_ _R VCC < 5.5V, MAX8_ _L/M 24 VCC < 3.6V, MAX8_ _R/S/T/Z 17 35 60 VCC < 3.6V, MAX8_ _R/S/T/Z 60 TA = +25°C 4.56 TA = -40°C to +85°C 4.50 4.75 TA = -40°C to +125°C 4.40 4.86 4.63 4.31 TA = -40°C to +85°C 4.25 4.50 TA = -40°C to +125°C 4.16 4.56 3.93 3.89 TA = -40°C to +125°C 3.80 TA = +25°C 3.04 TA = -40°C to +85°C 3.00 TA = -40°C to +125°C 2.92 TA = +25°C 2.89 TA = -40°C to +85°C 2.85 4.38 4.00 μA 4.70 TA = +25°C TA = -40°C to +85°C V 30 VCC < 5.5V, MAX8_ _L/M TA = +25°C UNITS 5.5 TA = -40°C to +85°C MAX8_ _M 2 MAX 5.5 MAX8_ _L Reset Threshold (SOT only) TYP 1.0 TA = -40°C to +85°C Supply Current (SC70) MIN TA = 0°C to +70°C 4.45 4.06 4.10 4.20 3.08 3.11 3.15 3.23 2.93 2.96 3.00 TA = -40°C to +125°C 2.78 TA = +25°C 2.59 3.08 TA = -40°C to +85°C 2.55 2.70 TA = -40°C to +125°C 2.50 2.76 2.63 _______________________________________________________________________________________ 2.66 V 3-Pin Microprocessor Reset Circuits (VCC = full range, TA = -40°C to +105°C (SOT23) or TA = -40°C to +125°C (SC70), 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 MAX8_ _L MAX8_ _M MAX8_ _T Reset Threshold (SC70 only) VTH MAX8_ _S MAX8_ _R MAX8_ _Z (SC70 only) MIN TYP MAX TA = +25°C 4.56 4.63 4.70 TA = -40°C to +85°C 4.50 4.75 TA = -40°C to +125°C 4.44 4.82 TA = +25°C 4.31 TA = -40°C to +85°C 4.25 4.50 TA = -40°C to +125°C 4.20 4.56 3.04 TA = -40°C to +85°C 3.00 3.15 TA = -40°C to +125°C 2.95 3.21 TA = +25°C 2.89 TA = -40°C to +85°C 2.85 3.00 TA = -40°C to +125°C 2.81 3.05 2.63 2.96 2.59 TA = -40°C to +85°C 2.55 2.70 TA = -40°C to +125°C 2.52 2.74 2.32 2.28 TA = -40°C to +85°C 2.25 2.38 TA = -40°C to +125°C 2.22 2.42 2.35 30 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 +125°C 100 VOL VOH VOL ppm/°C 20 240 μs 560 840 240 460 840 VCC = VTH min, I SINK = 1.2mA, MAX803R/S/T/Z, MAX809R/S/T/Z 0.3 VCC = VTH min, I SINK = 3.2mA, MAX803L/M, MAX809J/L/M 0.4 VCC > 1.0V, I SINK = 50μA 0.3 VCC > VTH max, ISOURCE = 500μA, MAX803R/S/T/Z, MAX809R/S/T/Z 0.8VCC VCC > VTH max, ISOURCE = 800μA, MAX803L/M, MAX809J/L/M VCC - 1.5 V 2.66 TA = +25°C VCC = VTH to (VTH - 100mV) RESET Output Voltage Low (push-pull active high, MAX810) 2.93 3.11 TA = +25°C VCC to Reset Delay (Note 2) RESET Output Voltage High (push-pull active low MAX809) 3.08 4.45 TA = +25°C Reset Threshold Tempco RESET Output Voltage Low (push-pull active low and opendrain active low, MAX803 and MAX809) 4.38 UNITS 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 _______________________________________________________________________________________ 3 MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z ELECTRICAL CHARACTERISTICS (continued) ELECTRICAL CHARACTERISTICS (continued) (VCC = full range, TA = -40°C to +105°C (SOT23) or TA = -40°C to +125°C (SC70), 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 RESET Output Voltage High (push-pull active high, MAX810) VOH CONDITIONS MIN 1.8V < VCC < VTH min, I SOURCE = 150μA RESET Open-Drain Output Leakage Current (MAX803) (Note 3) TYP MAX UNITS 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. Note 3: Guaranteed by design, not production tested. 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.) MAX8_ _R/S/T, VCC = 3.3V 10 MAX8_ _Z, VCC = 2.5V 5 80 MAX803-TOC3 VOD = VTH - VCC VOD = 10mV 60 VOD = 20mV 40 VOD = 100mV 20 140 -40 -20 0 20 40 60 85 20 0 40 TEMPERATURE (°C) -20 -40 TEMPERATURE (°C) 60 60 40 VOD = 200mV 0 -40 85 -20 20 0 40 TEMPERATURE (°C) 1.002 NORMALIZED THRESHOLD 245 MAX8_ _J/L/M 240 MAX8_ _R/S/T/Z 235 230 MAX803-TOC6 1.003 MAX803-TOC5 250 POWER-UP RESET TIMEOUT (ms) VOD = 100mV 20 NORMALIZED RESET THRESHOLD vs. TEMPERATURE POWER-UP RESET TIMEOUT vs. TEMPERATURE 1.001 1.000 0.999 0.998 0.997 225 -40 -20 0 20 40 TEMPERATURE (°C) 4 VOD = 20mV 80 VOD = 200mV 0 VOD = 10mV 100 MAX8_ _L/M/R/S/T/Z, VCC = 1V 0 VOD = VTH - VCC 120 POWER-DOWN RESET DELAY (μs) MAX803 toc01 MAX8_ _L/M, VCC = 5V 100 POWER-DOWN RESET DELAY (μs) 15 POWER-DOWN RESET DELAY vs. TEMPERATURE (MAX8_ _J/L/M) POWER-DOWN RESET DELAY vs. TEMPERATURE (MAX8_ _R/S/T/Z) 60 85 -40 -20 MAX803-TOC4 SUPPLY CURRENT vs. TEMPERATURE (SC70 PACKAGE, NO LOAD) SUPPLY CURRENT (μA) 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 20 40 60 TEMPERATURE (°C) _______________________________________________________________________________________ 85 60 85 3-Pin Microprocessor Reset Circuits PART/SUFFIX RESET THRESHOLD (V) OUTPUT TYPE 4.63 4.38 3.08 2.93 2.63 2.32 4.63 4.38 4.00 3.08 2.93 2.63 2.32 4.63 4.38 3.08 2.93 2.63 2.32 OPEN-DRAIN RESET OPEN-DRAIN RESET OPEN-DRAIN RESET OPEN-DRAIN RESET OPEN-DRAIN RESET OPEN-DRAIN RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET MAX803L MAX803M MAX803T MAX803S MAX803R MAX803Z MAX809L MAX809M MAX809J MAX809T MAX809S MAX809R MAX809Z MAX810L MAX810M MAX810T MAX810S MAX810R MAX810Z 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 pullup resistor on the MAX803’s RESET output to any supply between 0 and 6V. Pin Description PIN NAME 1 GND 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 FUNCTION Ground TOP MARK SOT SC70 ⎯ ⎯ ⎯ ⎯ ⎯ ⎯ AAAA ABAA CWAA ACAA ADAA AFAA ⎯ AGAA AHAA AJAA AKAA ALAA ⎯ AAZ ABA ABB ABC ABD ABE AAN AAO ⎯ AAP AAQ AAR AAS AAT AAU AAV AAX AAW AAY Applications Information Negative-Going VCC Transients 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 = 0V When VCC falls below 1V, the MAX809 RESET output no longer sinks current—it becomes an open circuit. _______________________________________________________________________________________ 5 MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z Selector Guide 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 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 pullup 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 pullup resistor allows either device to assert reset (Figure 3). MAX803 Open-Drain RESET Output Allows Use with Multiple Supplies Generally, the pullup 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 400 MAXIMUM TRANSIENT DURATION (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 TA = +25°C 320 VCC 240 MAX809 RESET 160 MAX8_ _J/L/M 80 R1 100k GND MAX8_ _R/S/T/Z 0 1 10 100 1000 RESET COMPARATOR OVERDRIVE, VTH - VCC (mV) Figure 2. RESET Valid to VCC = Ground Circuit Figure 1. Maximum Transient Duration Without Causing a Reset Pulse vs. Reset Comparator Overdrive +5.0V +3.3V VCC VCC VCC VCC VCC RPULLUP μP MAX803 RESET RESET INPUT 5V SYSTEM MAX803 MOTOROLA 68HCXX RESET RESET INPUT GND GND Figure 3. Interfacing to µPs with Bidirectional Reset I/O 6 GND GND Figure 4. MAX803 Open-Drain RESET Output Allows Use with Multiple Supplies _______________________________________________________________________________________ 3-Pin Microprocessor Reset Circuits 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. Chip Information TRANSISTOR COUNT: 275 (SOT23) 380 (SC70) Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 3 SC70 X3-2 21-0075 3 SOT23 U3-1 21-0051 _______________________________________________________________________________________ 7 MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z below 1V, so does the IC’s ability to sink current at RESET. Also, with any pullup, RESET will be pulled high as VCC decays toward 0. The voltage where this occurs depends on the pullup resistor value and the voltage to which it is connected. MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z 3-Pin Microprocessor Reset Circuits Revision History REVISION NUMBER REVISION DATE 0 12/94 7 2/10 DESCRIPTION Initial release. PAGES CHANGED — Updated Ordering information, added lead-free note, and added soldering temperature in the Absolute Maximum Ratings. 1, 2 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 © 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.