MXD1815XR

19-2243; Rev 0; 10/01 Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 General Description 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 R ESET 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 o Precision Monitoring of +2.5V, +3V, +3.3V, and +5V Power-Supply Voltages o Available in Four Reset Output Configurations o Factory-Set Reset Threshold Voltages: 2.18V, 2.31V, 2.55V, 2.88V, 3.06V, 4.12V, 4.37V, 4.62V o ±2.5% Reset Threshold Accuracy Over Temperature o Fixed Reset Timeout Period: 100ms (min) o Guaranteed RESET/RESET Valid to VCC = +1V o Debounced Manual Reset Detect (MXD1813/MXD1818) o Power-Supply Transient Immunity o No External Components o Low Power Consumption (4µA) o Pin Compatible with DS181_ Products (SOT23) o 3-Pin SC70 and SOT23 Packages MXD1810–MXD1813/MXD1815–MXD1818* Ordering Information PART† MXD1810UR_ _-T MXD1810XR_ _-T †The TEMP. RANGE -40oC to +105oC -40oC to +105oC PIN-PACKAGE 3 SOT23-3 3 SC70-3 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 Printers Automotive Systems Critical µP and µC Monitoring Portable/Battery-Powered Equipment *Patent pending MXD181_X RESET 2 (RESET) Pin Configurations TOP VIEW VCC 1 3 GND VCC 2 RESET 1 (RESET) MXD181_U 3 GND SC70-3 SOT23-3 () ARE FOR THE MXD1812/MXD1817 ________________________________________________________________ Maxim Integrated Products 1 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. Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 MXD1810–MXD1813/MXD1815–MXD1818 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 Supply Voltage Range Supply Current SYMBOL VCC ICC CONDITIONS TA = 0°C to +105°C TA = -40°C to +105°C VCC = +5.5V, VCC > VTH, no load VCC = +3.6V, VCC > VTH, no load MXD181_ _ R46 MXD181_ _ R44 MXD181_ _ R41 Reset Threshold VTH MXD181_ _ R31 MXD181_ _ R29 MXD181_ _ R26 MXD181_ _ R23 MXD181_ _ R22 Active Reset Timeout Period VCC to Reset Delay Push-Button Detect to Reset Push-Button Reset Timeout Period Input Low Voltage Input High Voltage RESET Output Source Current RESET Output Source Current tRP tRD tPB tPBRST VIL VIH IOH IOH VCC rising VCC = (VTH + 100mV) falling to (VTH - 200mV) VCC rising, tR = 5µs MXD1813/MXD1818 only MXD1813/MXD1818 only MXD1813/MXD1818 only TA = +25°C to +105°C TA = -40°C to +25°C 0.7 × VCC 350 350 100 1.5 100 150 250 0.34 0.15 4.50 4.25 4.00 2.98 2.80 2.47 2.25 2.12 100 MIN 1.0 1.2 9 4 4.62 4.37 4.12 3.06 2.88 2.55 2.31 2.18 150 2 150 TYP MAX 5.5 5.5 16 10 4.75 4.49 4.24 3.15 2.97 2.64 2.37 2.25 250 5 250 ms µs ms µs ms V V µA µA V UNITS V µA MXD1813/MXD1818 only VCC ≥ VTH(MAX), reset not asserted, MXD1810/MXD1815 VCC ≤ VTH(MIN), reset asserted, MXD1812/MXD1817 VCC ≥ 2.7V, reset asserted, VOUT = 0.4V MXD1810/MXD1811/MXD1813/MXD1815/ MXD1816/MXD1818 (Note 2) VCC ≥ 2.7V, reset not asserted, , VOUT = 0.4V MXD1812/MXD1817 RESET Output Sink Current IOL 10 mA RESET Output Sink Current IOL 10 mA 2 _______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 ELECTRICAL CHARACTERISTICS (continued) (VCC = full range, TA = -40°C to +105°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note 1) PARAMETER Output High Voltage Output Capacitance (Note 2) Internal Pullup Resistor Open-Drain SYMBOL VOH COUT RP MXD1811/MXD1816 MXD1813/MXD1818 3.5 3.1 5.5 5.5 CONDITIONS 0 < IOH < 500µA MIN VCC 0.5 TYP VCC 0.1 10 7.5 7.5 MAX UNITS V pF kΩ MXD1810–MXD1813/MXD1815–MXD1818 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.) SUPPLY CURRENT vs. TEMPERATURE MXD1810-13/15-18 toc01 RESET TIMEOUT PERIOD vs. TEMPERATURE (VCC RISING) MXD1810-13/15-18 toc02 NORMALIZED RESET THRESHOLD vs. TEMPERATURE (VCC FALLING) MXD1810-13/15-18 toc03 10 RESET/RESET NOT ASSERTED 8 SUPPLY CURRENT (µA) VCC = +5V 1.010 NORMALIZED RESET THRESHOLD 160 TIMEOUT PERIOD (ms) 156 152 148 144 140 VCC = +2.5V VCC = +5V 1.005 VTH = +4.62V 1.000 VTH = +2.18V 0.995 6 4 VCC = +3.3V 2 VCC = +2.5V 0 -40 -10 20 50 80 110 TEMPERATURE (°C) 0.990 -40 -10 20 50 80 110 -40 -10 20 50 80 110 TEMPERATURE (°C) TEMPERATURE (°C) POWER-DOWN RESET DELAY vs. TEMPERATURE MXD1810-13/15-18 toc04 MAXIMUM TRANSIENT DURATION vs. RESET THRESHOLD OVERDRIVE MXD1810-13/15 toc05 OUTPUT VOLTAGE vs. OUTPUT SINK CURRENT MXD1810-13/15-18 toc06 3.0 POWER-DOWN RESET DELAY (µs) 2.5 VTH = +4.62V 2.0 1.5 1.0 0.5 0 -40 -10 20 50 80 110 TEMPERATURE (°C) 100 MAXIMUM TRANSIENT DURATION (µs) 90 80 70 60 50 40 30 20 10 0 RESET OCCURS ABOVE THIS LINE 200 160 OUTPUT VOLTAGE (mV) 120 80 VTH = +2.18V 40 0 10 100 1000 RESET THRESHOLD OVERDRIVE, VTH - VCC (mV) 0 3 6 9 12 15 OUTPUT CURRENT (mA) _______________________________________________________________________________________ 3 Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 MXD1810–MXD1813/MXD1815–MXD1818 Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) OUTPUT VOLTAGE vs. OUTPUT SOURCE CURRENT MXD1810-13/15-18 toc07 INPUT LOW VOLTAGE vs. VCC AND TEMPERATURE MXD1810-13/15 toc08 0.5 0.8 INPUT LOW VOLTAGE (V) 0.4 VCC - VOUT (V) VCC = +5.5V 0.6 0.3 0.2 0.4 VCC = +2.2V 0.1 0 0 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT CURRENT (mA) 0.2 -40 -10 20 50 80 110 TEMPERATURE (°C) Pin Descriptions MXD1810/MXD1815 PIN SC70 2 1 3 SOT23 1 2 3 RESET VCC GND 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. Supply Voltage and Input for Reset Threshold Monitor Ground NAME FUNCTION MXD1811/MXD1816 PIN SC70 2 1 3 SOT23 1 2 3 NAME FUNCTION 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. Supply Voltage and Input for Reset Threshold Monitor Ground RESET VCC GND 4 _______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 Pin Descriptions (continued) MXD1812/MXD1817 PIN SC70 2 1 3 SOT23 1 2 3 NAME FUNCTION 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. Supply Voltage and Input for Reset Threshold Monitor Ground MXD1810–MXD1813/MXD1815–MXD1818 RESET VCC GND 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. Supply Voltage and Input for Reset Threshold Monitor Ground 2 1 RESET 1 3 2 3 VCC GND 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. (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. 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 R ESET held for greater than 1.5µs asserts a reset. RESET deasserts following a 100ms minimum reset timeout delay 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 _______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 MXD1810–MXD1813/MXD1815–MXD1818 Functional Diagram MXD1810 MXD1812 MXD1815 MXD1817 VCC MXD1811 MXD1816 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 MXD1813 MXD1818 VCC The T ypical 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. MR MONITOR Ensuring a Valid Reset Output Down to VCC = 0 RESET RESET GENERATOR VREF Figure 3. Functional Diagram, Open-Drain Active-Low Output with Manual Reset Detection 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 R ESET 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/ 6 _______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 MXD1810–MXD1813/MXD1815–MXD1818 VCC VTH VCC MXD1813 MXD1818 tRP VCC(MIN) RESET VCC RESET RESET GND RESET tRP MANUAL RESET Figure 4. Power-Up Reset Timing Diagram Figure 5. Push-Button Manual Reset VCC tPBRST (OPEN) SWITCH BOUNCE EXTERNAL PUSH BUTTON (CLOSED) tPBRST 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 Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 MXD1810–MXD1813/MXD1815–MXD1818 VCC Table 1. Device Marking Codes PART VCC VCC MXD1811 MXD1816 µP RESET RESET GND GND TOP MARK SOT23 FZIV FZKD FZKC FZKF FZIW FZKE FZKH FZKG FZIX FZIY FZKJ FZKI FZKN FZIZ FZKM FZKL FZKK FZKR FZKQ FZKP FZKO FZJA FZJB FZKV FZKU FZKT FZKS FZKY FZKX FZJC FZKW FZJE SC70 AEK AHU AHT AHW AEL AHV AHY AHX AEM AEN AIA AHZ AIE AEO AID AIC AIB AII AIH AIG AIF AEP AEQ AIM AIL AIK AIJ AIP AIO AER AIN AEV MXD1810_R46 MXD1810_R44 MXD1810_R41 MXD1811_R46 MXD1811_R44 MXD1811_R41 MXD1812_R46 MXD1812_R44 MXD1812_R41 Figure 7. Interfacing to Microprocessors with Bidirectional Reset Pins VCC MXD1813_R46 MXD1813_R44 MXD1813_R41 MXD1815_R31 MXD1815_R29 VCC VCC MXD1810 MXD1815 µP RESET RPULLDOWN* GND RESET GND MXD1815_R26 MXD1815_R23 MXD1815_R22 MXD1816_R31 MXD1816_R29 MXD1816_R26 MXD1816_R23 MXD1816_R22 *MXD1810/MXD1815 ONLY MXD1817_R31 MXD1817_R29 MXD1817_R26 MXD1817_R23 MXD1817_R22 MXD1818_R31 Figure 8. Ensuring Valid RESET Output Down to VCC = 0 (MXD1810/MXD1815 only) VCC VCC RPULLUP* VCC µP GND GND MXD1818_R29 MXD1818_R26 MXD1818_R23 MXD1818_R22 MXD1812 MXD1817 RESET RESET *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 Selector Guide OPEN-DRAIN RESET WITH PUSHBUTTON DETECT — — — ✔ — — — ✔ MXD1810–MXD1813/MXD1815–MXD1818 PART 5V SYSTEMS 2.5V/3.0V/3.3V SYSTEMS — — — — ✔ ✔ ✔ ✔ PUSH-PULL RESET ✔ — — — ✔ — — — OPEN-DRAIN RESET — ✔ — — — ✔ — — PUSH-PULL RESET — — ✔ — — — ✔ — MXD1810 MXD1811 MXD1812 MXD1813 MXD1815 MXD1816 MXD1817 MXD1818 ✔ ✔ ✔ ✔ — — — — Ordering Information (continued) PART† MXD1811UR_ _-T MXD1811XR_ _-T MXD1812UR_ _-T MXD1812XR_ _-T MXD1813UR_ _-T MXD1813XR_ _-T MXD1815UR_ _-T MXD1815XR_ _-T MXD1816UR_ _-T MXD1816XR_ _-T MXD1817UR_ _-T MXD1817XR_ _-T MXD1818UR_ _-T MXD1818XR_ _-T TEMP. RANGE -40 C to +105 C -40oC to +105oC -40oC to +105oC -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 -40oC to +105oC -40oC to +105oC -40 C to +105 C -40oC to +105oC o o o o o o o o o o o o o o o o o o Reset Threshold Table PART MXD1810–MXD1813 MXD1810–MXD1813 MXD1810–MXD1813 MXD1815–MXD1818 MXD1815–MXD1818 MXD1815–MXD1818 MXD1815–MXD1818 MXD1815–MXD1818 SUFFIX (_ _) 46 44 41 31 29 26 23 22 TYP. RESET THRESHOLD (V) * 4.62 4.37 4.12 3.06 2.88 2.55 2.31 2.18 PIN-PACKAGE 3 SOT23-3 3 SC70-3 3 SOT23-3 3 SC70-3 3 SOT23-3 3 SC70-3 3 SOT23-3 3 SC70-3 3 SOT23-3 3 SC70-3 3 SOT23-3 3 SC70-3 3 SOT23-3 3 SC70-3 *Factory-trimmed reset thresholds are nominally ±1.5% at room temperature. †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. Chip Information TRANSISTOR COUNT: 709 PROCESS TECHNOLOGY: BiCMOS _______________________________________________________________________________________ 9 Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 MXD1810–MXD1813/MXD1815–MXD1818 Package Information SC70, 3L.EPS 10 ______________________________________________________________________________________ Low-Power µP Reset Circuits in 3-Pin SC70/SOT23 Package Information (continued) SOTPO3L.EPS MXD1810–MXD1813/MXD1815–MXD1818 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.