19-1946; Rev 1; 2/01 4-Pin, Low-Power µP Reset Circuits with Manual Reset These devices perform a single function: they assert a reset signal whenever the VCC supply voltage declines below a preset threshold or whenever manual reset is asserted. Reset remains asserted for a preset timeout period after VCC has risen above the reset threshold or after manual reset is deasserted. The only difference among the three devices is their output. The MAX6804 (push/pull) and MAX6805 (open-drain) have an activelow RESET output, while the MAX6803 (push/pull) has an active-high RESET output. The MAX6803/MAX6804 are guaranteed to be in the correct state for VCC down to 0.7V. The MAX6805 is guaranteed to be in the correct state for VCC down to 1.0V. The reset comparator in these ICs is designed to ignore fast transients on VCC. Reset thresholds are factorytrimmable between 2.63V and 4.80V, in approximately 100mV increments. These devices are available with a 1ms min, 20ms min, or 100ms min reset timeout period. Ideal for space-critical applications, the MAX6803/ MAX6804/MAX6805 come packaged in a 4-pin SOT143. For a lower threshold voltage version, see the MAX6335/MAX6336/MAX6337. Features ♦ Ultra-Low 0.7V Operating Supply Voltage ♦ Low 4.0µA Supply Current ♦ Precision Monitoring of 2.85V to 5.0V PowerSupply Voltages ♦ Reset Thresholds Available from 2.63V to 4.80V, in Approximately 100mV Increments ♦ Debounced Manual Reset Input ♦ Fully Specified over Temperature ♦ Three Power-On Reset Timeout Periods Available (1ms min, 20ms min, 100ms min) ♦ Low Cost ♦ Three Available Output Structures: Push/Pull RESET, Push/Pull RESET, Open-Drain RESET ♦ Guaranteed RESET/RESET Valid to VCC = 0.7V (MAX6803/MAX6804) ♦ Power-Supply Transient Immunity ♦ No External Components Required ♦ 4-Pin SOT143 Package ♦ Pin Compatible with MAX811/MAX812 and MAX6314/MAX6315 Ordering Information Applications Computers PART* TEMP. RANGE PIN-PACKAGE Controllers MAX6803US_ _D_-T -40°C to +125°C 4 SOT143 Intelligent Instruments MAX6804US_ _D_-T Critical µP/µC Power Monitoring MAX6805US_ _D_-T -40°C to +125°C -40°C to +125°C 4 SOT143 4 SOT143 Portable/Battery-Powered Equipment Automotive Typical Operating Circuit and Pin Configuration appear at end of data sheet. *These devices are available in factory-set VCC reset thresholds from 2.63V to 4.80V, in approximately 0.1V increments. Choose the desired reset threshold suffix from Table 1 and insert it in the blanks following “US” in the part number. Factory-programmed reset timeout periods are also available. Insert the number corresponding to the desired nominal reset timeout period (1 = 1ms min, 2 = 20ms min, 3 = 100ms min) in the blank following “D” in the part number. There are 15 standard versions with a required order increment of 2500 pieces. Sample stock is generally held on the standard versions only (see Selector Guide). Contact the factory for availability of nonstandard versions (required order increment is 10,000 pieces). All devices available in tape-and-reel only. Selector Guide appears at end of data sheet. ________________________________________________________________ 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 MAX6803/MAX6804/MAX6805 General Description The MAX6803/MAX6804/MAX6805 microprocessor (µP) supervisory circuits monitor the power supplies in 2.85V to 5.0V µP and digital systems. They increase circuit reliability and reduce cost by eliminating external components and adjustments. They also feature a debounced manual reset input. MAX6803/MAX6804/MAX6805 4-Pin, Low-Power µP Reset Circuits with Manual Reset ABSOLUTE MAXIMUM RATINGS Terminal Voltage (with respect to GND) VCC ......................................................................-0.3V to +6V Push/Pull RESET or RESET, MR ............-0.3V to (VCC + 0.3V) Open-Drain RESET ..............................................-0.3V to +6V Input Current (VCC) .............................................................20mA Output Current (RESET, RESET).........................................20mA Continuous Power Dissipation (TA = +70°C) 4-Pin SOT143 (derate 4mW/°C above +70°C) ............320mW Operating Temperature Range .........................-40°C to +125°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 +125°C, unless otherwise noted. Typical values are at VCC = +5.0V and TA = +25°C, reset not asserted.) (Note 1) PARAMETER Supply Voltage Range (Note 1) SYMBOL CONDITIONS TA = 0°C to +125°C VCC TA = -40°C to +125°C Supply Current Reset Threshold MAX6803/MAX6804 MAX6805 1.0 5.5 0.78 5.5 MAX6805 1.2 5.5 4 10 5 12 VTH VTH + 1.8% VTH - 3% VTH VTH + 3% MAX680_US_ _D1-T 1 1.5 2 MAX680_US_ _D2-T 20 30 40 MAX680_US_ _D3-T 100 150 200 VTH MAX680_US_ _D_-T, Table 1 TA = +25°C V µA V VCC falling at 10V/ms MR Minimum Pulse Width 30 µs 1 ms µs MR Glitch Immunity 50 ns MR Reset Delay 0.1 µs MR Input Voltage 0.3 ✕ VCC VIL 0.7 ✕ VCC VIH MR Pullup Resistance RESET Output Low Voltage (MAX6804/MAX6805) RESET Output High Voltage (MAX6804) 2 VTH - 1.8% UNITS 5.5 VCC = +5.0V No load tRP MAX MAX6803/MAX6804 TA = -40°C to +125°C Reset Active Timeout Period TYP 0.7 VCC = +3.0V ICC VCC Falling Reset Delay MIN 12 VOL VOH Reset asserted Reset not asserted 20 30 ISINK = 50µA, VCC ≥ 1.0V 0.4 ISINK = 1.2mA, VCC ≥ 2.5V 0.3 ISINK = 3.2mA, VCC ≥ 4.25V 0.4 ISOURCE = 500µA, VCC ≥ 3.0V 0.8 ✕ VCC ISOURCE = 800µA, VCC ≥ 5.0V 0.8 ✕ VCC _______________________________________________________________________________________ V kΩ V V 4-Pin, Low-Power µP Reset Circuits with Manual Reset (VCC = full range, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VCC = +5.0V and TA = +25°C, reset not asserted.) (Note 1) PARAMETER SYMBOL CONDITIONS Reset asserted VOH RESET Output Voltage (MAX6803) Reset not asserted VOL RESET Output Leakage Current (MAX6805) MIN TYP ISOURCE = 1µA, VCC ≥ 1.0V 0.8 ✕ VCC ISOURCE = 200µA, VCC ≥ 1.8V 0.8 ✕ VCC ISOURCE = 800µA, VCC ≥ 4.25V 0.8 ✕ VCC MAX UNITS V ISINK = 1.2mA, VCC ≥ 3.0V 0.3 ISINK = 3.2mA, VCC ≥ 5.0V 0.4 VCC > VTH, RESET not asserted V 0.5 µA Note 1: All parts are production tested at TA = +25°C. Over temperature limits are guaranteed by design and not production tested. Note 2: ISOURCE for the MAX6803 is 100nA; ISINK for the MAX6804 is 100nA; ISINK for the MAX6805 is 50µA. __________________________________________Typical Operating Characteristics (Reset not asserted, TA = +25°C, unless otherwise noted.) 5.0 4.5 VCC = +3.3V 4.0 3.5 1.010 1.000 0.990 0.980 0.970 VTH = 2.93V ISINK = 500µA RESET 60 MAX6803/04/05 toc03 1.020 80 +125°C +85°C +25°C 40 -40°C 20 0.960 3.0 0.950 0 25 50 75 100 125 0 -50 -25 0 25 50 75 100 1.5 2.5 2.0 3.0 TEMPERATURE (°C) TEMPERATURE (°C) VCC (V) OUTPUT VOLTAGE HIGH vs. SUPPLY VOLTAGE MAXIMUM TRANSIENT DURATION vs. RESET COMPARATOR OVERDRIVE VCC FALLING PROPAGATION DELAY vs. TEMPERATURE 75 +125°C 50 +85°C +25°C 25 600 500 400 RESET OCCURS 300 200 RESET DOES NOT OCCUR 100 2.0 VCC (V) 2.5 3.0 80 70 VCC = FALLING AT 1V/ms 60 50 40 30 VCC = FALLING AT 10V/ms 10 0 0 1.5 90 20 -40°C 0 100 MAX6803/04/05 toc06 VTH = 2.93V ISINK = 100µA RESET ASSERTED (MAX6803) POROPAGATION DELAY (µs) 100 1.0 1.0 125 MAX6803/04/05 toc05 -25 MAX6803/04/05 toc04 -50 OUTPUT VOLTAGE HIGH (VCC - VOH) (mV) 1.030 MAXIMUM TRANSIENT DURATION (µs) ICC (µA) VCC = +5.0V 1.040 OUTPUT VOLTAGE LOW (mV) 5.5 MAX6803/04/05 toc02 6.0 1.050 NORMALIZED RESET TIMEOUT PERIOD MAX6803/04/05 toc01 6.5 OUTPUT VOLTAGE LOW vs. SUPPLY VOLTAGE NORMALIZED RESET TIMEOUT PERIOD vs. TEMPERATURE SUPPLY CURRENT vs. TEMPERATURE 0.1 1 10 100 1000 RESET COMPARATOR OVERDRIVE (mV) -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) _______________________________________________________________________________________ 3 MAX6803/MAX6804/MAX6805 ELECTRICAL CHARACTERISTICS (continued) MAX6803/MAX6804/MAX6805 4-Pin, Low-Power µP Reset Circuits with Manual Reset Pin Description PIN MAX6803 1 — MAX6804 MAX6805 1 2 NAME GND FUNCTION Ground RESET Active-Low Reset Output. RESET is asserted while VCC is below the reset threshold, or while MR is asserted. RESET remains asserted for a reset timeout period (tRP) after VCC rises above the reset threshold or MR is deasserted. RESET on the MAX6804 is push/pull. RESET on the MAX6805 is open-drain. Active-High Reset Output. RESET is asserted high while VCC is below the reset threshold or while MR is asserted, and RESET remains asserted for a reset timeout period (tRP) after VCC rises above the reset threshold or MR is deasserted. RESET on the MAX6803 is push/pull. 2 — RESET 3 3 MR Manual Reset Input. A logic low on MR asserts reset. Reset remains asserted as long as MR is low, and for the reset timeout period (tRP) after MR goes high. Leave unconnected or connect to VCC if not used. 4 4 VCC Supply Voltage Input Applications Information Manual Reset Input Many µP-based products require manual reset capability, allowing the operator, a test technician, or external logic circuitry to initiate a reset. A logic low on MR asserts reset. Reset remains asserted while MR is low, and for the reset active timeout period after MR returns high. MR has an internal 20kΩ pullup resistor, so it can be left unconnected if not used. Connect a normally open momentary switch from MR to GND to create a manual reset function; external debounce circuitry is not required. Interfacing to µPs with Bidirectional Reset Pins Since the RESET output on the MAX6805 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 1). 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 V CC transients (glitches). The Typical Operating Characteristics show the Maximum Transient Duration vs. Reset Comparator Overdrive graph. The graph 4 shows the maximum pulse width that a negative-going VCC transient may typically have without issuing a reset signal. As the amplitude of the transient increases, the maximum allowable pulse width decreases. Ensuring a Valid Reset Output down to VCC = 0 When VCC falls below 1V and approaches the minimum operating voltage of 0.7V, push/pull-structured reset sinking (or sourcing) capabilities decrease drastically. High-impedance CMOS-logic inputs connected to the RESET pin can drift to indeterminate voltages. This does not present a problem in most cases, since most VCC 100kΩ VCC VCC µP MOTOROLA 68HCXX MAX6805 MR RESET RESET GND GND Figure 1. Interfacing to µPs with Bidirectional Reset Pins _______________________________________________________________________________________ 4-Pin, Low-Power µP Reset Circuits with Manual Reset Since the MAX6805 has an open-drain, active-low output, it typically uses a pullup resistor. With this device, RESET will most likely not maintain an active condition, but will drift to a non-active level due to the pullup resistor and the reduced sinking capability of the opendrain device. Therefore, this device is not recommended for applications where the RESET pin is required to be valid down to VCC = 0. Pin Configuration VCC TOP VIEW MAX6804 MR 1 100kΩ GND (a) GND RESET 4 VCC 3 MR MAX6803 MAX6804 MAX6805 VCC RESET (RESET) 2 100kΩ* MAX6803 RESET MR (b) SOT143 ( ) ARE FOR MAX6803 GND Typical Operating Circuit *ASSUMES HIGH-Z RESET INPUT TO THE µP Figure 2. Ensuring Reset Valid down to VCC = 0 VCC VCC VCC MAX6804 µP MR RESET GND RESET GND PUSHBUTTON SWITCH _______________________________________________________________________________________ 5 MAX6803/MAX6804/MAX6805 µPs and circuitry do not operate when VCC drops below 1V. For the MAX6804 application where RESET must be valid down to 0, adding a pulldown resistor between RESET and GND removes stray leakage currents, holding RESET low (Figure 2a). The pulldown resistor value is not critical; 100kΩ is large enough not to load RESET, and small enough to pull it low. For the MAX6803, where RESET must be valid to VCC = 0, a 100kΩ pullup resistor between RESET and VCC will hold RESET high when VCC falls below 0.7V (Figure 2b). MAX6803/MAX6804/MAX6805 4-Pin, Low-Power µP Reset Circuits with Manual Reset Table 1. Factory-Trimmed Reset Thresholds 6 RESET THRESHOLD SUFFIX MIN TYP (VTH) MAX MIN MAX 48 4.714 4.80 4.886 4.656 4.944 47 4.615 4.70 4.785 4.559 4.841 46 4.547 4.63 4.713 4.491 4.769 45 4.419 4.50 4.581 4.365 4.635 44 4.301 4.38 4.459 4.249 4.511 43 4.223 4.30 4.377 4.171 4.429 42 4.124 4.20 4.276 4.074 4.326 41 4.026 4.10 4.174 3.977 4.223 40 3.928 4.00 4.072 3.880 4.120 39 4.830 3.90 3.970 3.783 4.017 38 3.732 3.80 3.868 3.686 3.914 37 3.633 3.70 3.767 3.589 3.811 36 3.535 3.60 3.665 3.492 3.708 35 3.437 3.50 3.563 3.395 3.605 34 3.339 3.40 3.461 3.298 3.502 33 3.241 3.30 3.359 3.201 3.399 32 3.142 3.20 3.258 3.104 3.296 31 3.025 3.08 3.135 2.988 3.172 30 2.946 3.00 3.054 2.910 3.090 29 2.877 2.93 2.983 2.842 3.018 28 2.750 2.80 2.850 2.716 2.884 27 2.651 2.70 2.749 2.619 2.781 26 2.583 2.63 2.677 2.551 2.709 TA = +25°C TA = -40°C to +125°C _______________________________________________________________________________________ 4-Pin, Low-Power µP Reset Circuits with Manual Reset PART OUTPUT STAGE NOMINAL VTH (V) MIN RESET TIMEOUT (ms) SOT TOP MARK MAX6803US26D3-T Push/Pull RESET 2.63 100 KACH MAX6803US29D3-T Push/Pull RESET 2.93 100 KACI MAX6803US31D3-T Push/Pull RESET 3.08 100 KACJ MAX6803US44D3-T Push/Pull RESET 4.38 100 KACK MAX6803US46D3-T Push/Pull RESET 4.63 100 KACL MAX6804US26D3-T Push/Pull RESET 2.63 100 KACN MAX6804US29D3-T Push/Pull RESET 2.93 100 KACP MAX6804US31D3-T Push/Pull RESET 3.08 100 KACQ MAX6804US44D3-T Push/Pull RESET 4.38 100 KACR MAX6804US46D3-T Push/Pull RESET 4.63 100 KACS MAX6805US26D3-T Open-Drain RESET 2.63 100 KACO MAX6805US29D3-T Open-Drain RESET 2.93 100 KACU MAX6805US31D3-T Open-Drain RESET 3.08 100 KACV MAX6805US44D3-T Open-Drain RESET 4.38 100 KACW MAX6805US46D3-T Open-Drain RESET 4.63 100 KACX *Sample stock is generally held on all standard versions. Chip Information TRANSISTOR COUNT: 505 PROCESS: BiCMOS _______________________________________________________________________________________ 7 MAX6803/MAX6804/MAX6805 Selector Guide (Standard Versions*) 4-Pin, Low-Power µP Reset Circuits with Manual Reset SOT1434.EPS MAX6803/MAX6804/MAX6805 Package Information 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 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.