19-2243; Rev 0; 10/01 Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 The MXD1810–MXD1813/MXD1815–MXD1818 family of microprocessor (µP) reset circuits monitor power supplies in µP and digital systems. These devices provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +2.5V/+3.0V/+3.3V (MXD1815–MXD1818), and +5V (MXD1810–MXD1813) systems. These circuits assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping reset asserted for at least 100ms after VCC rises above the reset threshold. The MXD1813/ MXD1818 also keep reset asserted for at least 100ms after the output is momentarily pulled to GND by an external push-button switch. The MXD1812/MXD1817 have an active-high push-pull RESET output. The MXD1810/MXD1815 (push-pull) and MXD1811/MXD1813/MXD1816/MD1818 (open-drain) have an active-low RESET output. The open-drain devices (MXD1811/MXD1813/MXD1816/MXD1818) have an internal pullup resistor to V CC . The MXD1813/MXD1818 feature a debounced manual reset feature that asserts a reset if the RESET pin is pulled low for more than 1.5µs. When used to initiate manual reset, RESET debounces signals from devices such as mechanical switches. For devices with this feature, the release of the external switch triggers the reset period. The MXD1810–MXD1813/MXD1815–MXD1818 are guaranteed to output the correct logic state for VCC down to +1V. These ICs provide a reset comparator designed to ignore fast transients on V CC . Reset thresholds are available between +2.18V and +4.62V. These small, low-power (4µA) devices are ideal for use in portable equipment. All are available in space-saving 3-pin SC70 and SOT23 packages, and are specified from -40°C to +105°C. Features ♦ Precision Monitoring of +2.5V, +3V, +3.3V, and +5V Power-Supply Voltages ♦ Available in Four Reset Output Configurations ♦ Factory-Set Reset Threshold Voltages: 2.18V, 2.31V, 2.55V, 2.88V, 3.06V, 4.12V, 4.37V, 4.62V ♦ ±2.5% Reset Threshold Accuracy Over Temperature ♦ Fixed Reset Timeout Period: 100ms (min) ♦ Guaranteed RESET/RESET Valid to VCC = +1V ♦ Debounced Manual Reset Detect (MXD1813/MXD1818) ♦ Power-Supply Transient Immunity ♦ No External Components ♦ Low Power Consumption (4µA) ♦ Pin Compatible with DS181_ Products (SOT23) ♦ 3-Pin SC70 and SOT23 Packages Ordering Information PART† TEMP. RANGE -40oC to +105oC 3 SOT23-3 MXD1810XR_ _-T -40oC to +105oC 3 SC70-3 †The MXD1810–MXD1813/MXD1815–MXD1818 are available with factory-set VCC reset thresholds from +2.18V to +3.06V (MXD1815–MXD1818) and +4.12V to +4.62V (MXD1810– MXD1813). Choose the desired reset-threshold suffix from the Reset Threshold Table and insert it in place of the “_ _” following “R” in the part number. All devices are available in tapeand-reel only in 2500 unit increments. Other threshold voltages may be available. Contact factory for availability. Ordering Information continued at end of data sheet. Applications Computers and Controllers Intelligent Instruments Set-Top Boxes Pin Configurations TOP VIEW VCC RESET 1 (RESET) 1 Printers Automotive Systems Critical µP and µC Monitoring Portable/Battery-Powered Equipment *Patent pending PIN-PACKAGE MXD1810UR_ _-T MXD181_X RESET 2 (RESET) 3 GND MXD181_U VCC SC70-3 3 GND 2 SOT23-3 () ARE FOR THE MXD1812/MXD1817 ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MXD1810–MXD1813/MXD1815–MXD1818* General Description MXD1810–MXD1813/MXD1815–MXD1818 Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +6.0V Push-Pull RESET (MXD1810/MXD1815), RESET (MXD1812/MXD1817) to GND.....-0.3V to (VCC + 0.3V) Open-Drain RESET (MXD1811/MXD1816) to GND................................................................-0.3V to +6.0V Open-Drain RESET (MXD1813/MXD1818) to GND ....................................................-0.3V to (VCC + 0.3V) Input Current (VCC, RESET) ................................................20mA Output Current (RESET, RESET).........................................20mA Continuous Power Dissipation (TA = +70°C) 3-Pin SC70 (derate 2.17mW above +70°C) ..................174mW 3-Pin SOT23 (derate 4mW/°C above +70°C) ...............320mW Operating Temperature Range .........................-40°C to +105°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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 specified. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL Supply Voltage Range VCC Supply Current ICC Reset Threshold Active Reset Timeout Period VTH tRP CONDITIONS MIN MAX 1.0 5.5 TA = -40°C to +105°C 1.2 5.5 VCC = +5.5V, VCC > VTH, no load 9 16 VCC = +3.6V, VCC > VTH, no load 4 10 UNITS V µA MXD181_ _ R46 4.50 4.62 4.75 MXD181_ _ R44 4.25 4.37 4.49 MXD181_ _ R41 4.00 4.12 4.24 MXD181_ _ R31 2.98 3.06 3.15 MXD181_ _ R29 2.80 2.88 2.97 MXD181_ _ R26 2.47 2.55 2.64 MXD181_ _ R23 2.25 2.31 2.37 MXD181_ _ R22 2.12 2.18 2.25 VCC rising 100 150 250 ms 2 5 µs 150 250 ms 150 250 ms VCC = (VTH + 100mV) falling to (VTH - 200mV) VCC to Reset Delay tRD VCC rising, tR = 5µs 100 Push-Button Detect to Reset tPB MXD1813/MXD1818 only 1.5 tPBRST MXD1813/MXD1818 only 100 Push-Button Reset Timeout Period TYP TA = 0°C to +105°C V µs TA = +25°C to +105°C 0.34 TA = -40°C to +25°C 0.15 Input Low Voltage VIL MXD1813/MXD1818 only Input High Voltage VIH MXD1813/MXD1818 only RESET Output Source Current IOH VCC ≥ VTH(MAX), reset not asserted, MXD1810/MXD1815 350 µA RESET Output Source Current IOH VCC ≤ VTH(MIN), reset asserted, MXD1812/MXD1817 350 µA RESET Output Sink Current IOL VCC ≥ 2.7V, reset asserted, VOUT = 0.4V MXD1810/MXD1811/MXD1813/MXD1815/ MXD1816/MXD1818 (Note 2) 10 mA RESET Output Sink Current IOL VCC ≥ 2.7V, reset not asserted, , VOUT = 0.4V MXD1812/MXD1817 10 mA 2 0.7 × VCC V V _______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 (VCC = full range, TA = -40°C to +105°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL Output High Voltage VOH Output Capacitance (Note 2) COUT Internal Pullup Resistor Open-Drain CONDITIONS 0 < IOH < 500µA MIN TYP VCC 0.5 VCC 0.1 MAX UNITS V 10 RP MXD1811/MXD1816 3.5 5.5 7.5 MXD1813/MXD1818 3.1 5.5 7.5 pF kΩ Note 1: Production testing done at TA = +25°C; limits over temperature guaranteed by design. Note 2: The MXD1811/MXD1813/MXD1816/MXD1818 have an internal pullup resistor which may deliver 1mA of sink current. Note 3: Guaranteed by design. Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) VCC = +3.3V VCC = +2.5V VCC = +2.5V 148 144 0 140 -10 20 50 80 110 MXD1810-13/15-18 toc03 VTH = +4.62V 1.000 VTH = +2.18V 0.995 0.990 -40 -10 20 50 80 110 -40 -10 20 50 80 110 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) POWER-DOWN RESET DELAY vs. TEMPERATURE MAXIMUM TRANSIENT DURATION vs. RESET THRESHOLD OVERDRIVE OUTPUT VOLTAGE vs. OUTPUT SINK CURRENT 2.5 VTH = +4.62V 2.0 1.5 1.0 VTH = +2.18V 0.5 100 90 80 70 60 RESET OCCURS ABOVE THIS LINE 50 40 30 20 200 MXD1810-13/15-18 toc06 MXD1810-13/15-18 toc04 3.0 MAXIMUM TRANSIENT DURATION (µs) -40 POWER-DOWN RESET DELAY (µs) 152 1.005 160 OUTPUT VOLTAGE (mV) 2 VCC = +5V 1.010 NORMALIZED RESET THRESHOLD 4 156 MXD1810-13/15 toc05 SUPPLY CURRENT (µA) 6 MXD1810-13/15-18 toc02 VCC = +5V 8 160 TIMEOUT PERIOD (ms) RESET/RESET NOT ASSERTED MXD1810-13/15-18 toc01 10 NORMALIZED RESET THRESHOLD vs. TEMPERATURE (VCC FALLING) RESET TIMEOUT PERIOD vs. TEMPERATURE (VCC RISING) SUPPLY CURRENT vs. TEMPERATURE 120 80 40 10 0 0 0 -40 -10 20 50 80 TEMPERATURE (°C) 110 10 100 1000 RESET THRESHOLD OVERDRIVE, VTH - VCC (mV) 0 3 6 9 12 15 OUTPUT CURRENT (mA) _______________________________________________________________________________________ 3 MXD1810–MXD1813/MXD1815–MXD1818 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) OUTPUT VOLTAGE vs. OUTPUT SOURCE CURRENT INPUT LOW VOLTAGE vs. VCC AND TEMPERATURE 0.3 0.2 VCC = +5.5V 0.6 0.4 VCC = +2.2V 0.1 0 MXD1810-13/15 toc08 0.4 0.8 INPUT LOW VOLTAGE (V) MXD1810-13/15-18 toc07 0.5 VCC - VOUT (V) MXD1810–MXD1813/MXD1815–MXD1818 Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 0.2 0 0.5 1.0 1.5 2.0 2.5 3.0 -40 20 -10 OUTPUT CURRENT (mA) 50 80 110 TEMPERATURE (°C) Pin Descriptions MXD1810/MXD1815 PIN NAME FUNCTION SC70 SOT23 2 1 RESET 1 2 VCC Supply Voltage and Input for Reset Threshold Monitor 3 3 GND Ground Push-Pull, Active-Low Reset Output. RESET changes from high to low when VCC drops below the selected reset threshold. RESET remains low for the reset timeout period after VCC exceeds the device reset threshold. MXD1811/MXD1816 PIN 4 NAME FUNCTION SC70 SOT23 2 1 1 2 VCC Supply Voltage and Input for Reset Threshold Monitor 3 3 GND Ground RESET Open-Drain, Active-Low Reset Output. RESET changes from high to low when VCC drops below the selected reset threshold. RESET remains low for the reset timeout period after VCC exceeds the device reset threshold. RESET has an internal 5.5kΩ pullup resistor. _______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 MXD1812/MXD1817 PIN NAME FUNCTION SC70 SOT23 2 1 1 2 VCC Supply Voltage and Input for Reset Threshold Monitor 3 3 GND Ground RESET Push-Pull, Active-High Reset Output. RESET changes from low to high when VCC drops below the selected reset threshold. RESET remains high for the reset timeout period after VCC exceeds the device reset threshold. MXD1813/MXD1818 PIN SC70 SOT23 NAME FUNCTION Open-Drain, Active-Low Reset Output with Manual Reset Detect. RESET changes from high to low when VCC drops below the selected reset threshold, or RESET is externally pulled low for at least 1.5µs. RESET remains low for the reset timeout period after VCC exceeds the device reset threshold or after the external manual reset is released. RESET has an internal 5.5kΩ pullup resistor. 2 1 RESET 1 2 VCC Supply Voltage and Input for Reset Threshold Monitor 3 3 GND Ground Detailed Description RESET/RESET Output A microprocessor’s (µP’s) reset input starts the microprocessor in a known state. The MXD1810–MXD1813/ MXD1815–MXD1818 µP supervisory circuits assert reset to prevent code-execution errors during powerup, power-down, and brownout conditions (Figure 4). Whenever VCC falls below the reset threshold, the reset output asserts. Once VCC exceeds the reset threshold, an internal timer keeps the reset output asserted for the specified reset timeout period (tRP). Reset is also triggered by an externally initiated rising edge on the RESET pin (MXD1813/MXD1818), following a low signal of 1.5µs minimum duration. Push-Button Reset (MXD1813/MXD1818) Many µP-based products require push-button reset capability (Figure 5), allowing the operator, a test technician, or external logic circuitry to initiate reset. On the MXD1813/MXD1818, a logic-low on RESET held for greater than 1.5µs asserts a reset. RESET deasserts following a 100ms minimum reset timeout delay (tPBRST). A manual reset input shorter than 1.5µs may release RESET without the 100ms minimum reset timeout delay. To facilitate use with mechanical switches, the MXD1813/MXD1818 contain internal debouncing circuitry. A debounced waveform is shown in Figure 6. Applications Information Interfacing to µPs with Bidirectional Reset Pins Since the RESET output on the MXD1811/MXD1816 is open drain, these devices interface 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 allows either device to assert reset (Figure 7). No external pullup resistor is required, as it is contained within the MXD1811/MXD1816. Negative-Going VCC Transients In addition to issuing a reset to the µP during power-up, power-down, and brownout conditions, these devices are relatively immune to short-duration, negative-going VCC transients (glitches). _______________________________________________________________________________________ 5 MXD1810–MXD1813/MXD1815–MXD1818 Pin Descriptions (continued) MXD1810–MXD1813/MXD1815–MXD1818 Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 Functional Diagram MXD1810 MXD1812 MXD1815 MXD1817 MXD1811 MXD1816 VCC VCC RESET RESET GENERATOR RESET GENERATOR RESET OR RESET VREF VREF Figure 1. Functional Diagram, Push-Pull Output Figure 2. Functional Diagram, Open-Drain Active-Low Output The Typical Operating Characteristics show the Maximum Transient Duration vs. Reset Threshold Overdrive for which reset pulses are not generated. The graph shows the maximum pulse width that a negativegoing VCC transient may typically have without issuing a reset signal. As the amplitude of the transient increases, the maximum allowable pulse width decreases. MXD1813 MXD1818 VCC Ensuring a Valid Reset Output Down to VCC = 0 MR MONITOR RESET GENERATOR RESET VREF Figure 3. Functional Diagram, Open-Drain Active-Low Output with Manual Reset Detection 6 When VCC falls below the minimum operating voltage, push-pull structured reset sinking (or sourcing) capabilities decrease dramatically. High-impedance CMOSlogic inputs connected to the RESET/RESET pin can drift to indeterminate voltages. This does not present a problem in most cases, since most µPs and circuitry do not operate at V CC below +1V. For MXD1810/ MXD1815 applications where RESET must be valid down to VCC = 0, adding a pulldown resistor between RESET and GND removes stray leakage currents, holding RESET low (Figure 8). The pulldown resistor value is not critical; 100kΩ is large enough not to load RESET and small enough to pull RESET low. For MXD1812/ _______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 MXD1810–MXD1813/MXD1815–MXD1818 VCC VTH VCC VCC MXD1813 MXD1818 tRP RESET RESET VCC(MIN) RESET GND MANUAL RESET tRP RESET Figure 5. Push-Button Manual Reset Figure 4. Power-Up Reset Timing Diagram VCC tPBRST tPBRST (OPEN) SWITCH BOUNCE EXTERNAL PUSH BUTTON (CLOSED) RESET Figure 6. Manual Reset Timing Diagram MXD1817 applications where RESET must be valid to VCC = 0, a 100kΩ pullup resistor between RESET and VCC holds RESET high when VCC falls below the minimum operating voltage (Figure 9). The MXD1811/MXD1813/MXD1816/MXD1818 have open-drain, active-low outputs with a pullup resistor included internal to the devices. While using these devices RESET will most likely not maintain an active condition when the supply voltage drops below the minimum VCC, but will drift to a nonactive level due to the pullup resistor and the reduced sinking capability of the open-drain output. Therefore, these devices are not recommended for applications where the RESET pin is required to be valid at VCC = 0. _______________________________________________________________________________________ 7 MXD1810–MXD1813/MXD1815–MXD1818 Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 Table 1. Device Marking Codes VCC PART SC70 MXD1810_R46 FZIV AEK MXD1810_R44 FZKD AHU MXD1810_R41 FZKC AHT MXD1811_R46 FZKF AHW MXD1811_R44 FZIW AEL MXD1811_R41 FZKE AHV MXD1812_R46 FZKH AHY MXD1812_R44 FZKG AHX MXD1812_R41 FZIX AEM MXD1813_R46 FZIY AEN MXD1813_R44 FZKJ AIA MXD1813_R41 FZKI AHZ MXD1815_R31 FZKN AIE MXD1815_R29 FZIZ AEO MXD1815_R26 FZKM AID MXD1815_R23 FZKL AIC MXD1815_R22 FZKK AIB VCC VCC MXD1811 MXD1816 µP RESET RESET GND GND Figure 7. Interfacing to Microprocessors with Bidirectional Reset Pins VCC VCC VCC MXD1810 MXD1815 µP RESET RESET GND RPULLDOWN* GND *MXD1810/MXD1815 ONLY Figure 8. Ensuring Valid RESET Output Down to VCC = 0 (MXD1810/MXD1815 only) VCC VCC RPULLUP* MXD1812 MXD1817 RESET VCC RESET µP TOP MARK SOT23 MXD1816_R31 FZKR AII MXD1816_R29 FZKQ AIH MXD1816_R26 FZKP AIG MXD1816_R23 FZKO AIF MXD1816_R22 FZJA AEP MXD1817_R31 FZJB AEQ MXD1817_R29 FZKV AIM MXD1817_R26 FZKU AIL MXD1817_R23 FZKT AIK MXD1817_R22 FZKS AIJ MXD1818_R31 FZKY AIP MXD1818_R29 FZKX AIO MXD1818_R26 FZJC AER MXD1818_R23 FZKW AIN MXD1818_R22 FZJE AEV GND GND *MXD1812/MXD1817 ONLY Figure 9. Ensuring Valid RESET Output Down to VCC = 0 (MXD1812/MXD1817 only) 8 _______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 PUSH-PULL RESET OPEN-DRAIN RESET PUSH-PULL RESET — ✔ — — OPEN-DRAIN RESET WITH PUSHBUTTON DETECT — — — ✔ — — ✔ — — — ✔ — MXD1813 ✔ — — — — ✔ MXD1815 — ✔ ✔ — — — MXD1816 — ✔ — ✔ — — MXD1817 — ✔ — — ✔ — MXD1818 — ✔ — — — ✔ PART 5V SYSTEMS 2.5V/3.0V/3.3V SYSTEMS MXD1810 ✔ MXD1811 ✔ MXD1812 Reset Threshold Table Ordering Information (continued) PART† TEMP. RANGE o o PIN-PACKAGE PART SUFFIX (_ _) TYP. RESET THRESHOLD (V) * 3 SC70-3 MXD1810–MXD1813 46 4.62 3 SOT23-3 MXD1810–MXD1813 44 4.37 41 4.12 MXD1811UR_ _-T -40 C to +105 C 3 SOT23-3 MXD1811XR_ _-T -40oC to +105oC MXD1812UR_ _-T -40oC to +105oC MXD1812XR_ _-T MXD1813UR_ _-T MXD1813XR_ _-T MXD1815UR_ _-T MXD1815XR_ _-T MXD1816UR_ _-T o o 3 SC70-3 MXD1810–MXD1813 o o 3 SOT23-3 MXD1815–MXD1818 31 3.06 o o 3 SC70-3 MXD1815–MXD1818 29 2.88 o o 3 SOT23-3 MXD1815–MXD1818 26 2.55 o o 3 SC70-3 MXD1815–MXD1818 23 2.31 o o 3 SOT23-3 MXD1815–MXD1818 22 2.18 o o -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 MXD1816XR_ _-T -40 C to +105 C 3 SC70-3 MXD1817UR_ _-T -40oC to +105oC 3 SOT23-3 MXD1817XR_ _-T -40oC to +105oC 3 SC70-3 o o MXD1818UR_ _-T -40 C to +105 C 3 SOT23-3 MXD1818XR_ _-T -40oC to +105oC 3 SC70-3 †The MXD1810–MXD1813/MXD1815–MXD1818 are available with factory-set VCC reset thresholds from +2.18V to +3.06V (MXD1815–MXD1818) and +4.12V to +4.62V (MXD1810– MXD1813). Choose the desired reset-threshold suffix from the Reset Threshold Table and insert it in place of the “_ _” following “R” in the part number. All devices are available in tapeand-reel only in 2500 unit increments. Other threshold voltages may be available. Contact factory for availability. *Factory-trimmed reset thresholds are nominally ±1.5% at room temperature. Chip Information TRANSISTOR COUNT: 709 PROCESS TECHNOLOGY: BiCMOS _______________________________________________________________________________________ 9 MXD1810–MXD1813/MXD1815–MXD1818 Selector Guide Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 SC70, 3L.EPS MXD1810–MXD1813/MXD1815–MXD1818 Package Information 10 ______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 SOTPO3L.EPS 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 11 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MXD1810–MXD1813/MXD1815–MXD1818 Package Information (continued)