MAX6746MAX6753 P Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay General Description Benefits and Features Configurable Reset and Watchdog Options Enables The MAX6746MAX6753 low-power microprocessor Wide Variety of Applications (P) supervisory circuits monitor single/dual system Factory-Set Reset Threshold Options from 1.575V supply voltages from 1.575V to 5V and provide maximum to 5V in ~100mV Increments adjustability for reset and watchdog functions. These Adjustable Reset Threshold Options devices assert a reset signal whenever the V CC Single/Dual Voltage Monitoring supply voltage or RESET IN falls below its reset threshold Capacitor-Adjustable Reset Timeout or when manual reset is pulled low. The reset output Capacitor-Adjustable Watchdog Timeout remains asserted for the reset timeout period after V CC Min/Max (Windowed) Watchdog Option and RESET IN rise above the reset threshold. The reset Manual-Reset Input Option function features immunity to power-supply transients. Push-Pull or Open-Drain RESET Output Options The MAX6746MAX6753 have 2% factory-trimmed 3.7A Supply Current Reduces System Power reset threshold voltages in approximately 100mV Consumption increments from 1.575V to 5.0V and/or adjustable reset threshold voltages using external resistors. Integrated Power Supply Protection Increases Robustness The reset and watchdog delays are adjustable with Power-Supply Transient Immunity external capacitors. The MAX6746MAX6751 contain a watchdog select input that extends the watchdog Guaranteed RESET Valid for V 1V CC timeout period by 128x. The MAX6752/MAX6753 contain 8-Pin SOT23 Packages Saves Board Space a window watchdog timer that looks for activity outside an Selector Guide and Ordering Information appear at end of expected window of operation. data sheet. The MAX6746MAX6753 are available with a push-pull or open-drain active-low RESET output. The MAX6746 Typical Operating Circuit MAX6753 are available in an 8-pin SOT23 package and are fully specified over the automotive temperature range V IN MAX6749 (-40C to +125C). MAX4751 Applications V CC Medical Equipment Automotive R1 Intelligent Instruments RESET IN V CC Portable Equipment P Battery-Powered Computers/Controllers MAX6748 Embedded Controllers MAX6749 Critical P Monitoring R2 MAX6750 Set-Top Boxes MAX6751 RESET RESET Computers GND SRT C SRT WDI I/O SWT WDS C SWT WDS = 0 FOR NORMAL MODE WDS = V FOR EXTENDED MODE CC 19-2530 Rev 15 1/17MAX6746MAX6753 P Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay Absolute Maximum Ratings V to GND...........................................................-0.3V to +6.0V Continuous Power Dissipation (T = +70C) CC A SRT, SWT, SET0, SET1, RESET IN, WDS, MR, 8-Pin SOT23 (derate 8.9mW/C above +70C)...........714mW WDI, to GND......................................-0.3V to (V + 0.3V) Operating Temperature Range .........................-40C to +125C CC RESET (Push-Pull) to GND....................-0.3V to (V + 0.3V) Storage Temperature Range ............................-65C to +150C CC RESET (Open-Drain) to GND.............................-0.3V to +6.0V Junction Temperature......................................................+150C Input Current (All Pins).....................................................20mA Lead Temperature (soldering, 10s) .................................+300C Output Current (RESET) ...................................................20mA Soldering Temperature (reflow) .......................................+260C 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 (V = +1.2V to +5.5V, T = T to T , unless otherwise specified. Typical values are at V = +5V and T = +25C.) (Note 1) CC A MIN MAX CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS T = 0C to +125C 1.0 5.5 A Supply Voltage V V CC T = -40C to 0C 1.2 5.5 A V 5.5V 5 10 CC Supply Current I V 3.3V 4.2 9 A CC CC V 2.0V 3.7 8 CC See V V - V + TH TH TH V Reset Threshold V T = -40C to +125C V CC TH A selection table 2% 2% Hysteresis V 0.8 % HYST V Reset Threshold CC TA = -40C to +125C 3.136 3.224 V (MAX6752AKA32 Only) Hysteresis V 0.65 0.80 0.90 % HYST (MAX6752AKA32 Only) V falling from V + 100mV to V CC TH TH V to Reset Delay 20 s CC -100mV at 1mV/s C = 1500pF 5.692 7.590 9.487 SRT Reset Timeout Period t ms RP C = 100pF 0.506 SRT SRT Ramp Current I V = 0 to 1.23V V = 1.6V to 5V 200 250 300 nA RAMP SRT CC SRT Ramp Threshold V V = 1.6V to 5V (V rising) 1.173 1.235 1.297 V RAMP CC RAMP C = 1500pF 5.692 7.590 9.487 Normal Watchdog Timeout Period SWT t ms WD (MAX6746MAX6751) C = 100pF 0.506 SWT C = 1500pF 728.6 971.5 1214.4 Extended Watchdog Timeout SWT t ms WD (MAX6746MAX6751) C = 100pF 64.77 SWT C = 1500pF 728.6 971.5 1214.4 Slow Watchdog Period SWT t ms WD2 (MAX6752/MAX6753) C = 100pF 64.77 SWT Fast Watchdog Timeout Period, C = 1500pF 91.08 121.43 151.80 SWT SET Ratio = 8, t ms WD1 C = 100pF 8.09 (MAX6752/MAX6753) SWT Fast Watchdog Timeout Period, C = 1500pF 45.53 60.71 75.89 SWT SET Ratio = 16, t ms WD1 C = 100pF 4.05 (MAX6752/MAX6753) SWT Maxim Integrated 2 www.maximintegrated.com