MAX6421XS25+T

Click here for production status of specific part numbers. MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay General Description The MAX6340/MAX6421–MAX6426 low-power microprocessor supervisor circuits monitor system voltages from 1.6V to 5V. These devices perform a single function: they assert a reset signal whenever the VCC supply voltage falls below its reset threshold. The reset output remains asserted for the reset timeout period after VCC rises above the reset threshold. The reset timeout is externally set by a capacitor to provide more flexibility. Benefits and Features ●● Monitor System Voltages from 1.6V to 5V ●● Capacitor-Adjustable Reset Timeout Period ●● Low Quiescent Current (1.6µA typ) ●● Three RESET Output Options Push-Pull RESET Push-Pull RESET Open-Drain RESET The MAX6421/MAX6424 have an active-low, pushpull reset output. The MAX6422 has an active-high, pushpull reset output and the MAX6340/MAX6423/ MAX6425/ MAX6426 have an active-low, open-drain reset output. The MAX6421/MAX6422/MAX6423 are offered in 4-pin SC70 or SOT143 packages. The MAX6340/MAX6424/ MAX6425/MAX6426 are available in 5-pin SOT23-5 packages. ●● Guaranteed Reset Valid to VCC = 1V ●● Immune to Short VCC Transients Applications ●● MAX6426 Pin Compatible with PST92XX ●● ●● ●● ●● ●● ●● ●● ●● ●● Portable Equipment Battery-Powered Computers/Controllers Automotive Medical Equipment Intelligent Instruments Embedded Controllers Critical µP Monitoring Set-Top Boxes Computers Pin Configurations TOP VIEW VCC 1 MAX6421X MAX6422X MAX6423X GND 2 4 RESET (RESET) 3 SRT SC70 ( ) ARE FOR THE MAX6422 Pin Configurations continued at end of data sheet. 19-2440; Rev 10; 5/18 ●● Small 4-Pin SC70, 4-Pin SOT143, and 5-Pin SOT23 Packages ●● MAX6340 Pin Compatible with LP3470 ●● MAX6424/MAX6425 Pin Compatible with NCP300–NCP303, MC33464/MC33465, S807/S808/S809, and RN5VD ●● AEC-Q100 Qualified (MAX6340UK31/V+T) Typical Operating Circuit, Selector Guide, and Ordering Information appear at end of data sheet. MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Absolute Maximum Ratings All Voltages Referenced to GND VCC........................................................................-0.3V to +6.0V SRT, RESET, RESET (push-pull).............. -0.3V to (VCC + 0.3V) RESET (open drain)..............................................-0.3V to +6.0V Input Current (all pins).......................................................±20mA Output Current (RESET, RESET).....................................±20mA Continuous Power Dissipation (TA = +70°C) 4-Pin SC70 (derate 3.1mW/°C above +70°C)..............245mW 4-Pin SOT143 (derate 4mW/°C above +70°C)............320mW 5-Pin SOT23 (derate 7.1mW/°C above +70°C)...........571mW Operating Temperature Range.......................... -40°C to +125°C Storage Temperature Range............................ .-65°C to +150°C Junction Temperature.......................................................+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 = 1V to 5.5V, TA = TMIN to TMAX, unless otherwise specified. Typical values are at VCC = 5V and TA = +25°C.) (Note 1) PARAMETER Supply Voltage Range Supply Current VCC Reset Threshold Accuracy Hysteresis VCC to Reset Delay Reset Timeout Period VSRT Ramp Current VSRT Ramp Threshold SYMBOL VCC ICC VTH VHYST tRD tRP IRAMP VTH-RAMP RAMP Threshold Hysteresis RESET Output Voltage Low VOL VOH RESET Output Leakage Current, Open-Drain ILKG VOH VOL TYP 1.0 MAX UNITS 5.5 V VCC ≤ 5.0V 2.5 4.2 VCC ≤ 3.3V 1.9 3.4 VCC ≤ 2.0V 1.6 2.5 TA = +25°C TA = -40°C to +125°C VCC falling at 1mV/µs CSRT = 1500pF VTH - 1.5% VTH + 1.5% VTH - 2.5% VTH + 2.5% 4 x VTH 80 3.00 4.375 µA V mV µs 5.75 ms CSRT = 0 0.275 VCC = 1.6V to 5V (VRAMP rising) 0.65 V 33 mV VSRT = 0 to 0.65V; VCC = 1.6V to 5V 240 nA VCC ≥ 1.0V, ISINK = 50µA 0.3 VCC ≥ 4.5V, ISINK = 3.2mA 0.4 VCC ≥ 2.7V, ISINK = 1.2mA 0.3 VCC ≥ 1.8V, ISOURCE = 200µA 0.8 x VCC VCC ≥ 4.5V, ISOURCE = 800µA 0.8 x VCC VCC ≥ 2.25V, ISOURCE = 500µA 0.8 x VCC VCC > VTH, reset not asserted 0.8 x VCC VCC ≥ 2.7V, ISOURCE = 500µA 0.8 x VCC VCC ≥ 1.8V, ISOURCE = 150µA VCC ≥ 1.8V, ISINK = 500µA 0.8 x VCC 0.8 x VCC VCC ≥ 2.7V, ISINK = 1.2mA VCC ≥ 4.5V, ISINK = 3.2mA V V 1.0 VCC ≥ 1.0V, ISOURCE = 1µA VCC ≥ 4.5V, ISOURCE = 800µA RESET Output Voltage Low MIN VRAMP falling threshold RESET Output Voltage High, Push-Pull RESET Output Voltage High CONDITIONS µA V 0.3 0.3 V 0.4 Note 1: Devices production tested at +25°C. Overtemperature limits are guaranteed by design. www.maximintegrated.com Maxim Integrated │  2 MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Typical Operating Characteristics (VCC = 5V, CSRT = 1500pF, TA = +25°C, unless otherwise noted.) 2.0 TA = -40°C 1.5 1.0 0.5 0 0 1 2 3 4 5 100 10 1 0.1 0.001 6 0.01 500 400 350 300 200 0 50 25 75 100 125 TEMPERATURE (°C) 160 150 0 200 400 600 800 RESET 400s/div 100 140 125 130 120 110 100 80 1000 -50 -25 0 25 75 50 TEMPERATURE (°C) 100 125 MAX6421/26 toc08 1.006 NORMALIZED RESET THRESHOLD 1V/div 75 NORMALIZED RESET THRESHOLD vs. TEMPERATURE MAX6421/26 toc07 VTH = 1.6V 50 VCC FALLING AT 1mVs RESET THRESHOLD OVERDRIVE (mV) VCC 25 90 VTH = 2.95V POWER-UP/POWER-DOWN CHARACTERISTIC 1V/div -25 VCC TO RESET DELAY vs. TEMPERATURE (VCC FALLING) RESET OCCURS ABOVE THE CURVE 0 -50 MAXIMUM TRANSIENT DURATION vs. RESET THRESHOLD OVERDRIVE 50 250 0 4.10 1000 100 75 4.15 TEMPERATURE (°C) 125 25 -25 100 150 450 -50 10 MAX6421/26 toc05 RESET TIMEOUT PERIOD (µs) 550 175 TRANSIENT DURATION (s) CSRT = 0 MAX6421/26 toc04 600 1 4.20 CSRT (nF) SUPPLY VOLTAGE (V) RESET TIMEOUT PERIOD vs. TEMPERATURE 0.1 4.25 MAX6421/26 toc06 TA = +25°C 2.5 CSRT = 1500pF RESET TIMEOUT PERIOD (ms) 3.0 1000 VCC TO RESET DELAY Sµs) TA = +125°C RESET TIMEOUT PERIOD vs. TEMPERATURE 4.30 MAX6421/26 toc02 10,000 RESET TIMEOUT PERIOD (ms) SUPPLY CURRENT (µA) 3.5 MAX6421/26 toc01 4.0 RESET TIMEOUT PERIOD vs. CSRT MAX6421/26 toc03 SUPPLY CURRENT vs. SUPPLY VOLTAGE 1.004 1.002 1.000 0.998 0.996 0.994 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) www.maximintegrated.com Maxim Integrated │  3 MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Pin Description PIN MAX6340 SOT23 MAX6421 MAX6422 MAX6423 SOT143 SC70 MAX6424 MAX6425 MAX6426 SOT23 SOT23 NAME FUNCTION 1 3 3 5 1 SRT Set Reset Timeout Input. Connect a capacitor between SRT and ground to set the timeout period. Determine the period as follows: tRP = 2.73 × 106 × CSRT + 275µs with tRP in seconds and CSRT in farads 2 1 2 3 2, 3 GND Ground 3 — — 4 — N.C. Not Internally Connected. Can be connected to GND 4 2 1 2 5 VCC Supply Voltage and Reset Threshold Monitor Input 5 4 1 4 RESET RESET changes from high to low whenever VCC drops below the selected reset threshold voltage. RESET remains low for the reset timeout period after VCC exceeds the reset threshold — — RESET RESET changes from low to high whenever VCC drops below the selected reset threshold voltage. RESET remains high for the reset timeout period after V CC exceeds the reset threshold 4 — Detailed Description 3.3V Reset Output The reset output is typically connected to the reset input of a µP. A µP’s reset input starts or restarts the µP in a known state. The MAX6340/MAX6421–MAX6426 µP supervisory circuits provide the reset logic to prevent code-execution errors during power-up, power-down, and brownout conditions (see Typical Operating Characteristics). RESET changes from high to low whenever VCC drops below the threshold voltage. Once VCC exceeds the threshold voltage, RESET remains low for the capacitor-adjustable reset timeout period. The MAX6422 active-high RESET output is the inverse logic of the active-low RESET output. All device outputs are guaranteed valid for VCC > 1V. The MAX6340/MAX6423/MAX6425/MAX6426 are opendrain RESET outputs. Connect an external pullup resistor to any supply from 0 to 5.5V. Select a resistor value large enough to register a logic low when RESET is asserted and small enough to register a logic high while supplying all input current and leakage paths connected to the RESET line. A 10kΩ to 100kΩ pullup is sufficient in most applications. www.maximintegrated.com VCC 5.0V LASER-TRIMMED RESISTORS VREF SRT CSRT RESET TIMEOUT 10kΩ RESET N MAX6340 MAX6423 MAX6425 MAX6426 5V SYSTEM GND Figure 1. MAX6340/MAX6423/MAX6425/MAX6426 Open-Drain RESET Output Allows Use with Multiple Supplies Selecting a Reset Capacitor The reset timeout period is adjustable to accommodate a variety of µP applications. Adjust the reset timeout period (tRP) by connecting a capacitor (CSRT) between SRT and ground. Calculate the reset timeout capacitor as follows: Maxim Integrated │  4 MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay CSRT = (tRP - 275µs) / (2.73 5 106) where tRP is in seconds and CSRT is in farads. The reset delay time is set by a current/capacitor-controlled ramp compared to an internal 0.65V reference. An internal 240nA ramp current source charges the external capacitor. The charge to the capacitor is cleared when a reset condition is detected. Once the reset condition is removed, the voltage on the capacitor ramps according to the formula: dV/dt = I/C. The CSRT capacitor must ramp to 0.65V to deassert the reset. CSRT must be a low-leakage (