Microprocessor a Supervisory Circuits ADM8696/ADM8697 FUNCTIONAL BLOCK DIAGRAMS FEATURES Upgrade for ADM696/ADM697, MAX696/MAX697 BATT ON Specified Over Temperature V Adjustable Low Line Voltage Monitor BATT Power OK/Reset Time Delay V OUT Reset Assertion Down to 1 V V CC Watchdog Timer100 ms, 1.6 s, or Adjustable V CC Low Switch On Resistance LL IN LOW LINE 0.7 V Normal, 7 V in Backup 400 nA Standby Current RESET Automatic Battery Backup Switching (ADM8696) RESET GENERATOR Fast On-Board Gating of Chip Enable Signals (ADM8697) RESET Voltage Monitor for Power Fail or Low Battery Warning OSC IN TIMEBASE FOR RESET Also Available in TSSOP Package AND WATCHDOG OSC SEL WATCHDOG WATCHDOG TIMER OUTPUT (WDO) WATCHDOG WATCHDOG INPUT (WDI) TRANSITION DETECTOR ADM8696 POWER FAIL INPUT (PFI) POWER FAIL OUTPUT (PFO) 1.3V GENERAL DESCRIPTION CE IN The ADM8696/ADM8697 supervisory circuits offer complete CE OUT single chip solutions for power supply monitoring and battery LL IN LOW LINE control functions in microprocessor systems. These functions include P reset, backup battery switchover, watchdog timer, RESET CMOS RAM write protection and power failure warning. RESET GENERATOR RESET The ADM8696/ADM8697 are available in 16-pin DIP and small OSC IN outline packages (including TSSOP) and provide the following TIMEBASE FOR RESET AND WATCHDOG OSC SEL functions: WATCHDOG WATCHDOG 1. Power-On Reset output during power-up, power-down and TIMER OUTPUT (WDO) brownout conditions. The RESET voltage threshold is WATCHDOG WATCHDOG adjustable using an external voltage divider. The RESET out- INPUT (WDI) TRANSITION DETECTOR put remains operational with V as low as 1 V. ADM8697 CC POWER FAIL INPUT (PFI) POWER FAIL 2. A Reset pulse if the optional watchdog timer has not been OUTPUT (PFO) 1.3V toggled within specified time. 3. Separate watchdog timeout and low line status outputs. 4. Adjustable reset and watchdog timeout periods. The ADM8696/ADM8697 is fabricated using an advanced epitaxial CMOS process combining low power consumption 5. A 1.3 V threshold detector for power fail warning, low battery (0.7 mW), extremely fast Chip Enable gating (2 ns) and high re- detection or to monitor a power supply other than V . CC liability. RESET assertion is guaranteed with V as low as 1 V. CC 6. Battery backup switching for CMOS RAM, CMOS micro- In addition, the power switching circuitry is designed for mini- processor or other low power logic (ADM8696). mal voltage drop thereby permitting increased output current drive 7. Write protection of CMOS RAM or EEPROM (ADM8697). of up to 100 mA without the need for an external pass transistor. 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 Tel: 617/329-4700 World Wide Web Site: (V = Full Operating Range, V = +2.8 V, T = T to T CC BATT A MIN MAX ADM8696/ADM8697SPECIFICATIONS unless otherwise noted.) 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 (ADM8696) V Output Voltage V 0.005 V 0.0025 V I = 1 mA OUT CC CC OUT V 0.2 V 0.125 V I 100 mA CC CC OUT V in Battery Backup Mode V 0.005 V 0.002 V I = 250 A, V < V 0.2 V OUT BATT BATT OUT CC BATT Supply Current (Excludes I ) 115 200 AI = 100 mA OUT OUT Supply Current in Battery Backup Mode 0.4 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 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 0.3 V I = 3.2 mA SINK BATT ON Output Short Circuit Current 30 mA BATT ON = V = 2.4 V Sink Current OUT 0.5 2.5 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 IN Reset Timeout Delay 35 50 70 ms OSC SEL = HIGH Watchdog Timeout Period, Internal Oscillator 1.0 1.6 2.25 s Long Period 70 100 140 ms Short Period Watchdog Timeout Period, External Clock 4032 4063 4097 Cycles Long Period 960 1011 1025 Cycles Short Period Minimum WDI Input Pulse Width 50 ns V = 0.8, V = 3.75 V, V = 5 V IL IH CC 100 ns V = 0.8, V = 3.5 V, V = 5 V IL IH CC 100 ns V = 0.8, V = 2.6 V, V = 3 V IL IH CC RESET Output Voltage V = +1 V 4 20 mV I = 10 A, V = 1 V CC SINK CC RESET, RESET Output Voltage 0.1 0.4 V I = 400 A, V = 2 V, V = 0 V SINK CC BATT 0.1 0.4 V I = 3.2 mA, 3 V < V < 5.5 V SINK CC 3.5 V I = 1 A, V = 5 V SOURCE CC 2.7 V I = 1 A, V = 3 V SOURCE CC LOW LINE, WDO Output Voltage 0.4 V I = 3.2 mA, SINK 3.5 V I = 1 A, V = 5 V SOURCE CC 2.7 V I = 1 A, V = 3 V SOURCE CC Output Short Circuit Source Current 1 10 25 AV = 5 V CC 1 WDI Input Threshold Logic Low 0.8 V Logic High 3.5 V V = 5 V CC 1.2 V V = 3 V CC WDI Input Current 1 10 A WD1 = V , (V ) OUT CC 10 1 A WD1 = 0 V POWER FAIL DETECTOR PFI Input Threshold 1.2 1.3 1.4 V PFILL Threshold Difference 50 15 +50 mV IN PFI Input Current 25 0.01 +25 nA LL Input Current 50 0.01 +50 nA IN PFO Output Voltage 0.4 V I = 3.2 mA SINK 3.5 V I = 1 A SOURCE 2.7 V I = 1 A, V = 3 V SOURCE CC PFO Short Circuit Source Current 1 10 25 A PFI = Low, PFO = 0 V CHIP ENABLE GATING (ADM8697) CE Threshold 0.8 V V IN IL 3.0 V V IH 1.2 V V = 3 V CC CE Pull-Up Current 3 A IN CE Output Voltage 0.4 V I = 3.2 mA OUT SINK V 0.5 V I = 800 A CC SOURCE CE Propagation Delay 2 7 ns V = 5.0 V CC 4nsV = 3.0 V CC OSCILLATOR OSC IN Input Current 2 A OSC SEL Input Pull-Up Current 5 A OSC IN Frequency Range 0 500 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 internally biased to 38% of V and has an input impedance of approximately 5 M. CC Specifications subject to change without notice. REV. A 2