MAX16997/MAX16998 High-Voltage Watchdog Timers with Adjustable Timeout Delay General Description Features The MAX16997/MAX16998 are microprocessor (P) Wide 5V to 40V Input Voltage Range supervisory circuits for high-input-voltage and low- 18A Quiescent Current (Typical at +125C) quiescent-current applications. These devices detect Capacitor-Adjustable Timeout Period for Watchdog downstream circuit failures and provide switchover to and Reset redundant circuitry. See the Selector Guide for the Windowed Watchdog Timer Options (MAX16998B/D) different versions of this product family. External Voltage Monitoring (RESETIN for the The MAX16997/MAX16998 family has four independent inputs for reset and watchdog functions. SWT and SRT MAX16998A/B/D and EN for the MAX16997A) inputs independently set the timeout periods of watchdog Car Battery-Compatible EN Input and reset timers through external capacitors. RESETIN/ TTL- and CMOS-Compatible Open-Drain Outputs EN monitor voltages at respective inputs. A resistive 18V Maximum Open-Drain Reset Output Voltage voltage-divider sets the reset threshold. 28V Maximum Open-Drain Enable Output Voltage The MAX16998A/B/D generate two output signals, RESET and ENABLE. RESET asserts whenever RESETIN drops Power-On/Power-Off Reset Functionality below its threshold voltage or when the watchdog timer (MAX16998A/B/D Only) detects a timing fault at WDI. Once asserted, and after AEC-Q100 Qualified all reset conditions are removed, RESET remains low -40C to +125C Operating Temperature Range for the reset timeout period, t , and then goes high. RESET The MAX16997A generates one output signal (ENABLE) Small (3mm x 3mm) MAX Package based on the voltage level at EN and the signal at WDI. WDI Narrow Pulse Immunity The MAX16997A does not have a RESET output. The watchdog is disabled if the voltage at EN is below its Ordering Information threshold. The MAX16997A watchdog timer starts timing when the voltage at EN becomes higher than the preset PART TEMP RANGE PIN-PACKAGE threshold voltage level. Each time EN rises above the pre- MAX16997AAUA+ -40C to +125C 8 MAX set threshold voltage, the initial watchdog timeout period MAX16998AAUA+ -40C to +125C 8 MAX is 8 times the normal watchdog timeout period (t ). WP MAX16998AAUA/V+ -40C to +125C 8 MAX The MAX16997/MAX16998 are available in 8-pin MAX16998BAUA+ -40C to +125C 8 MAX lead(Pb)-free MAX packages and are fully specified MAX16998BAUA/V+ -40C to +125C 8 MAX over the -40C to +125C automotive temperature range. MAX16998DAUA+ -40C to +125C 8 MAX MAX16998DAUA/V+ -40C to +125C 8 MAX Applications +Denotes a lead(Pb)-free/RoHS-compliant package. Automotive /V denotes an automotive qualified part. Industrial Pin Configurations appear at end of data sheet. Selector Guide WATCHDOG PART ENABLE RESET EN RESETIN WINDOW SIZE (%) MAX16997A 100 MAX16998A 100 MAX16998B 50 MAX16998D 75 MAX is a registered trademark of Maxim Integrated Products, Inc. 19-4000 Rev 5 4/19MAX16997/MAX16998 High-Voltage Watchdog Timers with Adjustable Timeout Delay Absolute Maximum Ratings (All pins referenced to GND, unless otherwise noted.) Continuous Power Dissipation (T = +70C) A IN, ENABLE............................................................-0.3V to +45V 8-Pin MAX (derate 4.8mW/C above +70C)..........387.8mW WDI, RESET, EN.....................................................-0.3V to +20V Operating Temperature Range (T )...................-40C to +125C A RESETIN................................................................-0.3V to +20V Junction Temperature (T )................................................+150C J SRT, SWT................................................................-0.3V to +12V Storage Temperature Range..............................-65C to +150C Maximum Current (all pins).................................................30mA Lead Temperature (soldering, 10s)...................................+300C 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. Package Thermal Characteristics (Note 1) Junction-to-Case Thermal Resistance ( ....................42C/W JC Junction-to-Ambient Thermal Resistance ( ) .............206.3C/W JA Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. Electrical Characteristics (V = 14V, T = T = -40C to +125C, unless otherwise noted. Typical values are at T = +25C.) (Note 2) IN A J A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Operating Voltage Range V 5.0 40.0 V IN T = -40C to +85C 18 30 A Supply Current I A IN T = -40C to +125C 18 60 A SWT Ramp Current I V = 1.0V 450 500 550 nA RAMP SWT SWT SRT Ramp Current I V = 1.0V 410 500 600 nA RAMP SRT SRT SWT/SRT Ramp Threshold V 1.115 1.235 1.363 V RAMP Voltage RESET TIMER V rising 1.135 1.255 1.383 Power-On Reset Input Threshold RESETIN V V PON Voltage V falling 1.115 1.235 1.363 RESETIN RESETIN Input Leakage Current I V = 2V 0.1 A LPON RESETIN RESET asserted, I = 1mA 0.9 SINK RESET Output Low Voltage V V = 1.1V, I = 160A, RESET asserted 0.4 V OLRST IN SINK RESET asserted, I = 0.4mA 0.4 SINK RESET Leakage Current I V = 20V, RESET not asserted 0.1 A LKGR RESET ENABLE Output Low Voltage V ENABLE asserted, I = 5mA 0.4 V OLEN SINK ENABLE Leakage Current I V = 14V, ENABLE not asserted 0.1 A LKGE ENABLE Minimum Reset Timeout Period t C = 390pF (Note 3) 1 ms RESETmin SRT Reset Timeout Period t C = 2000pF (Note 3) 5 ms RESET SRT Maximum Reset Time Period t C = 47nF 116.09 ms RESETmax SRT RESET to ENABLE Delay t 1.5 s REDL RESETIN falling below V to RESET PON RESETIN to RESET Delay t 1 s RRDL falling edge Maxim Integrated 2 www.maximintegrated.com