Microprocessor a Supervisory Circuits ADM696/ADM697 FUNCTIONAL BLOCK DIAGRAMS FEATURES Superior Upgrade for MAX696/MAX697 BATT ON Specified Over Temperature Adjustable Low Line Voltage Monitor V BATT Power OK/Reset Time Delay Reset Assertion Down to 1 V V V CC OUT Watchdog Timer100 ms, 1.6 s, or Adjustable V CC Low Switch On Resistance 1.5 V Normal, 20 V in Backup LL LOW LINE IN 600 nA Standby Current RESET Automatic Battery Backup Switching (ADM696) RESET GENERATOR Fast On-Board Gating of Chip Enable Signals (ADM697) RESET Voltage Monitor for Power Fail or Low Battery Warning OSC IN TIMEBASE FOR RESET APPLICATIONS AND WATCHDOG OSC SEL WATCHDOG WATCHDOG Microprocessor Systems TIMER OUTPUT (WDO) Computers WATCHDOG WATCHDOG Controllers TRANSITION DETECTOR INPUT (WDI) Intelligent Instruments ADM696 Automotive Systems POWER FAIL INPUT (PFI) POWER FAIL Critical mP Power Monitoring OUTPUT (PFO) 1.3V GENERAL DESCRIPTION The ADM696/ADM697 supervisory circuits offer complete CE IN CE OUT single chip solutions for power supply monitoring and battery LL IN control functions in microprocessor systems. These functions LOW LINE include P reset, backup-battery switchover, watchdog timer, RESET CMOS RAM write protection, and power failure warning. RESET GENERATOR The ADM696/ADM697 are available in 16-pin DIP and small RESET outline packages and provide the following functions: OSC IN TIMEBASE FOR RESET 1. Power-On Reset output during power-up, power-down and AND WATCHDOG OSC SEL WATCHDOG WATCHDOG brownout conditions. The RESET voltage threshold is TIMER OUTPUT (WDO) adjustable using an external voltage divider. The RESET WATCHDOG WATCHDOG output remains operational with V as low as 1 V. TRANSITION DETECTOR CC INPUT (WDI) 2. A Reset pulse if the optional watchdog timer has not been ADM697 POWER FAIL toggled within specified time. INPUT (PFI) POWER FAIL OUTPUT (PFO) 1.3V 3. Separate watchdog time-out and low line status outputs. 4. Adjustable reset and watchdog timeout periods. 5. A 1.3 V threshold detector for power fail warning, low bat- The ADM696/ADM697 is fabricated using an advanced epitaxial tery detection, or to monitor a power supply other than V . CC CMOS process combining low power consumption (5 mW), 6. Battery backup switching for CMOS RAM, CMOS micro- extremely fast Chip Enable gating (5 ns) and high reliability. processor or other low power logic (ADM696). RESET assertion is guaranteed with V as low as 1 V. In CC addition, the power switching circuitry is designed for minimal 7. Write protection of CMOS RAM or EEPROM (ADM697). voltage drop thereby permitting increased output current drive of up to 100 mA without the need for an external pass transistor. REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Tel: 617/329-4700 Fax: 617/326-8703(V = Full Operating Range, V = +2.8 V, T = T to T CC BATT A MIN MAX unless otherwise noted.) ADM696/ADM697SPECIFICATIONS Parameter Min Typ Max Units Test Conditions/Comments V Operating Voltage Range 3.0 5.5 V CC V Operating Voltage Range 2.0 V 0 3 V BATT CC BATTERY BACKUP SWITCHING (ADM696) V Output Voltage V 0.05 V 0.025 V I = 1 mA OUT CC CC OUT V 0.5 V 0.25 V I 100 mA CC CC OUT V in Battery Backup Mode V 0.05 V 0.02 V I = 250 A, V < V 0.2 V OUT BATT BATT OUT CC BATT Supply Current (Excludes I ) 1 1.95 mA I = 100 mA OUT OUT Supply Current in Battery Backup Mode 0.6 1 AV = 0 V, V = 2.8 V CC BATT Battery Standby Current 5.5 V > V > V + 0.2 V CC BATT (+ = Discharge, = Charge) 0.1 +0.02 AT = +25C A 1 +0.02 A Battery Switchover Threshold 70 mV Power-Up V V 50 mV Power-Down CC BATT Battery Switchover Hysteresis 20 mV BATT ON Output Voltage 0.4 V I = 1.6 mA SINK BATT ON Output Short Circuit Current 7 mA BATT ON = V = 2.4 V Sink Current OUT 0.5 1 25 A BATT ON = V , V = 0 V, Source Current OUT CC RESET AND WATCHDOG TIMER Low Line Threshold (LL ) 1.25 1.3 1.35 V V = +5 V, +3 V IN CC Reset Timeout Delay 35 50 70 ms OSC SEL = HIGH, V = 5 V, T = +25C CC A Watchdog Timeout Period, Internal Oscillator 1.0 1.6 2.25 s Long Period, V = 5 V, T = +25C CC A 70 100 140 ms Short Period, V = 5 V, T = +25C CC A Watchdog Timeout Period, External Clock 4032 4097 Cycles Long Period 960 1025 Cycles Short Period Minimum WDI Input Pulse Width 50 ns V = 0.4, V = 3.5 V, V = 5 V IL IH CC RESET Output Voltage V = +1 V 4 200 mV I = 10 A, V = 1 V CC SINK CC RESET, RESET Output Voltage 0.4 V I = 400 A, V = 2 V, V = 0 V SINK CC BATT 0.4 V I = 1.6 mA, 3 V < V < 5.5 V SINK CC 3.5 V I = 1 A, V = 5 V SOURCE CC LOW LINE, WDO Output Voltage 0.4 V I = 1.6 mA, SINK 3.5 V I = 1 A, V = 5 V SOURCE CC Output Short Circuit Source Current 1 3 25 A 1 WDI Input Threshold V = 5 V CC Logic Low 0.8 V Logic High 3.5 V WDI Input Current 20 50 A WD1 = V , (V ) T = +25C OUT CC A 50 15 A WD1 = 0 V, T = +25C A POWER FAIL DETECTOR PFI Input Threshold 1.2 1.3 1.4 V V = +3 V, +5 V CC PFILL Threshold Difference 50 15 +50 mV V = +3 V, +5 V IN CC PFI Input Current 25 0.01 +25 nA LL Input Current 50 0.01 +50 nA IN PFO Output Voltage 0.4 V I = 1.6 mA SINK 3.5 V I = 1 A, V = 5 V SOURCE CC PFO Short Circuit Source Current 1 3 25 A PFI = Low, PFO = 0 V CHIP ENABLE GATING (ADM697) CE Threshold 0.8 V V IN IL 3.0 V V , V = 5 V IH CC CE Pullup Current 3 A IN CE Output Voltage 0.4 V I = 1.6 mA OUT SINK V 0.5 V I = 800 A CC SOURCE CE Propagation Delay 5 25 ns OSCILLATOR OSC IN Input Current 2 A OSC SEL Input Pullup Current 5 A OSC IN Frequency Range 0 250 kHz OSC SEL = 0 V OSC IN Frequency with Ext. Capacitor 4 kHz OSC SEL = 0 V, C = 47 pF OSC NOTE 1 WDI is a three-level input which is internally biased to 38% of V and has an input impedance of approximately 125 k. CC Specifications subject to change without notice. 2 REV. 0