19-1412; Rev 0; 12/98 4-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits with Manual Reset The MAX6335/MAX6336/MAX6337 microprocessor (µP) supervisory circuits monitor the power supplies in 1.8V to 3.3V 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. 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 MAX6336 (push/pull) and MAX6337 (open-drain) have an activelow RESET output, while the MAX6335 (push/pull) has an active-high RESET output. The MAX6335/MAX6336 are guaranteed to be in the correct state for VCC down to 0.7V. The MAX6337 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 1.6V and 2.5V, in approximately 100mV increments. There are 15 standard versions available (2500 piece minimum-order quantity); contact the factory for availability of nonstandard versions (10,000 piece minimum-order quantity). For space-critical applications, the MAX6335/MAX6336/MAX6337 come packaged in a 4-pin SOT143. Features ♦ Ultra-Low 0.7V Operating Supply Voltage ♦ Low 3.3µA Supply Current ♦ Precision Monitoring of 1.8V and 2.5V PowerSupply Voltages ♦ Reset Thresholds Available from 1.6V to 2.5V, in Approximately 100mV Increments ♦ Debounced Manual Reset ♦ Fully Specified over Temperature ♦ Three Power-On Reset Pulse Widths 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 (MAX6335/MAX6336) ♦ Power-Supply Transient Immunity ♦ No External Components ♦ 4-Pin SOT143 Package ♦ Pin-Compatible with MAX811/MAX812 and MAX6314/MAX6315 Applications Ordering Information Pentium II™ Computers Computers PART* TEMP. RANGE PIN-PACKAGE Controllers MAX6335US__D_-T -40°C to +85°C 4 SOT143 Intelligent Instruments MAX6336US__D_-T Critical µP/µC Power Monitoring MAX6337US__D_-T -40°C to +85°C -40°C to +85°C 4 SOT143 4 SOT143 Portable/Battery-Powered Equipment Automotive Typical Operating Circuit and Pin Configuration appear at end of data sheet. Selector Guide appears at end of data sheet. * These devices are available in factory-set VCC reset thresholds from 1.6V to 2.5V, 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. Pentium II is a trademark of Intel Corp. ________________________________________________________________ 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. MAX6335/MAX6336/MAX6337 General Description MAX6335/MAX6336/MAX6337 4-Pin, Ultra-Low-Voltage, 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 Rate of Rise, VCC ............................................................100V/µs Continuous Power Dissipation (TA = +70°C) SOT143 (derate 4mW/°C above +70°C) .....................320mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+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, MR = VCC or unconnected, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C and VCC = 3V, reset not asserted.) PARAMETER SYMBOL CONDITIONS TA = 0°C to +85°C Supply Voltage Range VCC TA = -40°C to +85°C Supply Current Reset Threshold No load VTH MAX633_US_ _D_-T, Table 1 MAX 1.0 5.5 0.78 5.5 MAX6337 1.2 6.0 3.3 7.0 TA = +25°C VTH 1.8% VTH VTH + 1.8% TA = -40°C to +85°C VTH 3% VTH VTH + 3% 1 1.5 20 30 40 100 150 200 VOL Reset asserted ISINK = 50µA, VCC ≥ 1.0V 0.4 ISINK = 500µA, VCC ≥ 1.8V 0.3 RESET Output High Voltage (MAX6336) VOH Reset not asserted ISOURCE = 200µA, VCC ≥ 1.8V 0.8VCC ISOURCE = 500µA, VCC ≥ 2.7V 0.8VCC VOH Reset asserted ISOURCE = 1µA, VCC ≥ 1.0V 0.8VCC ISOURCE = 200µA, VCC ≥ 1.8V 0.8VCC VOL Reset not asserted ISINK = 500µA, VCC ≥ 1.8V 0.3 ISINK = 1.2mA, VCC ≥ 2.7V 0.3 1 MR Reset Delay VCC = 2.6V 0.42 RESET Output Leakage Current (MAX6337) 2 V µs 160 0.3VCC 12 V V VCC = 2.6V MR Pull-Up Resistance ms V MR Glitch Immunity MR Threshold V 2 MAX633_US_ _D3-T V MR µA µs 24 MAX633_US_ _D2-T MR Minimum Pulse Width V 5.5 3.0 RESET Output Low Voltage (MAX6336/MAX6337) RESET Output Voltage (MAX6335) UNITS 5.5 MAX6335/MAX6336 VCC falling at 10V/ms tRP TYP 0.7 MAX6337 MAX633_US_ _D1-T Reset Active Timeout Period MIN VCC = 1.8V VCC = 2.5V ICC VCC Falling Reset Delay MAX6335/MAX6336 20 VCC > VTH, RESET deasserted _______________________________________________________________________________________ ns µs 0.7VCC V 30 kΩ 0.5 µA 4-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits with Manual Reset NORMALIZED RESET TIMEOUT PERIOD vs. TEMPERATURE VCC = 2.5V 3.0 2.8 VCC = 1.8V 2.6 2.4 2.2 1.010 1.000 0.990 0.980 0.970 -20 0 20 40 60 80 100 50 40 TA = +25°C TA = +85°C 30 20 TA = -40°C 0 -60 -40 -20 0 20 40 60 80 100 0.50 1.00 1.50 2.00 2.50 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 140 120 100 80 60 TA = +25°C TA = -40°C 40 20 600 500 400 RESET OCCURS 300 200 RESET DOES NOT OCCUR 100 80 70 PROPAGATION DELAY (µs) VTH = 2.2V ISOURCE = 100µA RESET ASSERTED MAX6335/36/37 toc-5 160 MAX6335/36/37 toc-4 -40 60 10 0.950 -60 VTH = 2.5V ISINK = 500µA RESET ASSERTED 70 0.960 RESET NOT ASSERTED 2.0 OUTPUT VOLTAGE HIGH (VCC - VOH) (mV) 1.020 80 3.00 MAX6332/33/34 toc-6 3.2 1.030 MAXIMUM TRANSIENT DURATION (µs) ICC (µA) 3.4 VTH = 2.2V 1.040 MAX6335/36/37 toc-3 3.6 1.050 MAX6335/36/37-2 3.8 NORMALIZED RESET TIMEOUT PERIOD MAX6335/36/37 toc-1 4.0 OUTPUT VOLTAGE LOW vs. SUPPLY VOLTAGE OUTPUT VOLTAGE LOW (mV) SUPPLY CURRENT vs. TEMPERATURE 60 VCC FALLING AT 1V/ms 50 40 30 VCC FALLING AT 10V/ms 20 TA = +85°C 10 0 0 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5 VCC (V) 0.1 1 10 100 1000 RESET COMPARATOR OVERDRIVE (mV) -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) _______________________________________________________________________________________ 3 MAX6335/MAX6336/MAX6337 __________________________________________Typical Operating Characteristics (Reset not asserted, TA = +25°C, unless otherwise noted.) MAX6335/MAX6336/MAX6337 4-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits with Manual Reset Pin Description PIN MAX6335 1 — MAX6336 MAX6337 1 2 NAME GND FUNCTION Ground RESET Active-Low Reset Output. RESET remains low while VCC is below the reset threshold, or MR is asserted and for a reset timeout period (tRP) after VCC rises above the reset threshold, or MR is deasserted. RESET on the MAX6337 is open-drain. Active-High Reset Output. RESET remains high while VCC is below the reset threshold, or MR is asserted and for a reset timeout period (tRP) after VCC rises above the reset threshold, or MR is deasserted. RESET also asserts when MR is low. 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 (0.7V to 5.5V) Applications Information Manual-Reset Inputs 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 pull-up 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 MAX6337 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 1). 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 µPs and circuitry do not operate at VCC below 1V. For the MAX6336, where RESET must be valid down to 0, adding a pull-down resistor between RESET and GND removes stray leakage currents, holding RESET low VCC VCC VCC MAX6337 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 shows the maximum pulse width that a negative-going VCC transient may typically have without issuing a reset 4 MR RESET µP MOTOROLA 68HCXX RESET INPUT GND GND Figure 1. Interfacing to µPs with Bidirectional Reset Pins _______________________________________________________________________________________ 4-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits with Manual Reset MAX6336 MR RESET 100k GND (a) VCC 100k* MAX6335 RESET MR (b) GND RESET THRESHOLD SUFFIX MAX633_US25D_ MIN TYP MAX MIN MAX 2.46 2.50 2.55 2.43 2.58 MAX633_US24D_ 2.36 2.40 2.44 2.33 2.47 MAX633_US23D_ 2.26 2.30 2.34 2.23 2.37 MAX633_US22D_ 2.16 2.20 2.24 2.13 2.27 MAX633_US21D_ 2.06 2.10 2.14 2.04 2.16 MAX633_US20D_ 1.96 2.00 2.04 1.94 2.06 MAX633_US19D_ 1.87 1.90 1.93 1.84 1.96 MAX633_US18D_ 1.77 1.80 1.83 1.75 1.85 MAX633_US17D_ 1.67 1.70 1.73 1.65 1.75 MAX633_US16D_ 1.57 1.60 1.55 1.65 TA = +25°C 1.63 TA = -40°C to +85°C * Factory-trimmed reset thresholds are available in approximately 100mV increments, with a ±1.8% room-temperature variance. *ASSUMES HIGH-Z RESET INPUT TO THE µP Figure 2. Ensuring Reset Valid down to VCC = 0 (Figure 2a). The pull-down resistor value is not critical; 100kΩ is large enough not to load RESET, and small enough to pull it low. For the MAX6335, where RESET must be valid to VCC = 0, a 100kΩ pull-up resistor between RESET and VCC will hold RESET high when VCC falls below 0.7V (Figure 2b). Since the MAX6337 has an open-drain, active-low output, it typically uses a pull-up resistor. With this device, RESET will most likely not maintain an active condition, but will drift to a non-active level due to the pull-up 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. _______________________________________________________________________________________ 5 MAX6335/MAX6336/MAX6337 Table 1. Factory-Trimmed Reset Thresholds* VCC MAX6335/MAX6336/MAX6337 4-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits with Manual Reset Selector Guide (standard versions*) PART OUTPUT STAGE NOMINAL VTH (V) MINIMUM RESET TIMEOUT (ms) SOT TOP MARK MAX6335US23D3-T Push/Pull RESET 2.30 100 KABQ MAX6335US22D3-T Push/Pull RESET 2.20 100 KAAR MAX6335US20D3-T Push/Pull RESET 2.00 100 KABP MAX6335US18D3-T Push/Pull RESET 1.80 100 KAAQ MAX6335US16D3-T Push/Pull RESET 1.60 100 KAAP MAX6336US23D3-T Push/Pull RESET 2.30 100 KAAW MAX6336US22D3-T Push/Pull RESET 2.20 100 KAAV MAX6336US20D3-T Push/Pull RESET 2.00 100 KAAU MAX6336US18D3-T Push/Pull RESET 1.80 100 KAAT MAX6336US16D3-T Push/Pull RESET 1.60 100 KAAS MAX6337US23D3-T Open-Drain RESET 2.30 100 KABS MAX6337US22D3-T Open-Drain RESET 2.20 100 KAAZ MAX6337US20D3-T Open-Drain RESET 2.00 100 KABR MAX6337US18D3-T Open-Drain RESET 1.80 100 KAAY MAX6337US16D3-T Open-Drain RESET 1.60 100 KAAX * Sample stock is generally held on all standard versions. Pin Configuration TOP VIEW Typical Operating Circuit VCC GND 1 4 VCC MAX6335 MAX6336 MAX6337 RESET (RESET) 2 VCC MAX6335 MAX6336 µP MR 3 SOT143 VCC MR RESET (RESET) RESET GND PUSHBUTTON SWITCH ( ) ARE FOR MAX6335 6 GND _______________________________________________________________________________________ ( ) ARE FOR MAX6335 4-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits with Manual Reset TRANSISTOR COUNT: 505 SOT1434.EPS Package Information _______________________________________________________________________________________ 7 MAX6335/MAX6336/MAX6337 Chip Information 4-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits with Manual Reset MAX6335/MAX6336/MAX6337 NOTES 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 © 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.