LTC694-3.3/LTC695-3.3 3.3V Microprocessor Supervisory Circuits FEATURES DESCRIPTION n Guaranteed Reset Assertion at V = 1V The LTC 694-3.3/LTC695-3.3 provide complete 3.3V power CC n Pin Compatible with LTC694/LTC695 for 3.3V Systems supply monitoring and battery control functions. These n 200A Typical Supply Current include power-on reset, battery back-up, RAM write pro- n Fast (30ns Typ) Onboard Gating of tection, power failure warning and watchdog timing. The RAM Chip Enable Signals devices are pin compatible upgrades of the LTC694/LTC695 n SO-8 and S16 Packages that are optimized for 3.3V systems. Operating power n 2.90V Precision Voltage Monitor consumption has been reduced to 0.6mW (typical) and n Power OK/Reset Time Delay: 200ms or Adjustable 3W maximum in battery back-up mode. Microprocessor n Minimum External Component Count reset and memory write protection are provided when the n 1A Maximum Standby Current supply falls below 2.9V. The RESET output is guaranteed n Voltage Monitor for Power-Fail or to remain logic low with V as low as 1V. CC Low-Battery Warning The LTC694-3.3/LTC695-3.3 power the active RAMs with n Thermal Limiting a charge pumped NMOS power switch to achieve low n Performance Specified Over Temperature dropout and low supply current. When primary power is lost, auxiliary power, connected to the battery input pin, APPLICATIONS powers the RAMs in standby through an efficient PMOS switch. n 3.3V Low Power Systems n For an early warning of impending power failure, the Critical P Power Monitoring n LTC694-3.3/LTC695-3.3 provide an internal comparator Intelligent Instruments n with a user-defined threshold. An internal watchdog timer Battery-Powered Computers and Controllers n is also available, which forces the reset pins to active states Automotive Systems when the watchdog input is not toggled prior to a preset L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. timeout period. TYPICAL APPLICATION RESET Output Voltage vs Supply Voltage V 5V LT1129-3.3 IN 5 3.3V V V V V POWER TO P IN OUT CC OUT + + CMOS RAM POWER 0.1F 100F 0.1F 1F OUT SENSE LTC695-3.3 P 4 SYSTEM SHDN CE IN DECODER OUTPUT V GND BATT 3 CE OUT RAM CS 2.4V RESET P RESET 51k PFO P NMI PFI WDI I/O LINE 2 GND MICROPROCESSOR RESET, BATTERY BACK-UP, 18k 100 RAM WRITE PROTECTION, POWER WARNING AND 1 WATCHDOG TIMING ARE ALL IN A SINGLE CHIP FOR 3.3V MICROPROCESSOR SYSTEM 0.1F 0 694/5-3.3 TA01 0 1 2 3 4 5 SUPPLY VOLTAGE (V) 694/5-3.3 TA02 69453fb 1 RESET OUTPUT VOLTAGE (V)LTC694-3.3/LTC695-3.3 ABSOLUTE MAXIMUM RATINGS (Notes 1 and 2) Terminal Voltage V Output Current ................. Short-Circuit Protected OUT V .......................................................... 0.3V to 6V Power Dissipation ............................................. 500mW CC V ...................................................... 0.3V to 6V Operating Temperature Range BATT All Other Inputs ..................... 0.3V to (V + 0.3V) LTC694C-3.3/LTC695C-3.3 ...................... 0C to 70C OUT Input Current LTC694I-3.3/LTC695I-3.3 ....................40C to 85C V ..................................................................100mA Storage Temperature Range .................. 65C to 150C CC V .................................................................25mA Lead Temperature (Soldering, 10 sec)...................300C BATT GND ...................................................................10mA PIN CONFIGURATION TOP VIEW TOP VIEW V 1 16 RESET BATT V 1 16 RESET BATT V OUT V 2 15 RESET OUT 2 15 RESET V CC V 3 14 CC WDO 3 14 WDO GND 13 4 13 GND 4 CE IN CE IN BATT ON 5 12 BATT ON 5 12 CE OUT CE OUT LOW LINE 6 11 11 WDI WDI LOW LINE 6 OSC IN 7 10 PFO PFO 10 OSC IN 7 OSC SEL 8 9 PFI PFI OSC SEL 9 8 SW PACKAGE N PACKAGE 16-LEAD PLASTIC WIDE SO 16-LEAD PDIP T = 110C, = 130C/W JMAX JA T = 110C, = 130C/W JMAX JA TOP VIEW TOP VIEW V V OUT 1 8 V 1 BATT 8 V OUT BATT V 2 7 RESET V 2 7 RESET CC CC WDI GND 3 6 GND 3 6 WDI PFI 4 5 PFO PFI 4 5 PFO N8 PACKAGE S8 PACKAGE 8-LEAD PDIP 8-LEAD PLASTIC SO T = 110C, = 130C/W T = 110C, = 180C/W JMAX JA JMAX JA 69453fb 2