MAX818M

19-0494; Rev 1; 3/96 +5V Microprocessor Supervisory Circuits _______________General Description The MAX817/MAX818/MAX819 microprocessor (µP) supervisory circuits simplify power-supply monitoring, battery control, and chip-enable gating in µP systems by reducing the number of components required. These devices are designed for use in +5V-powered systems. Low supply current (11µA typical) and small package size make these devices ideal for portable applications. The MAX817/MAX818/MAX819 are specifically designed to ignore fast transients on VCC. Other supervisory functions include active-low reset, backupbattery switchover, watchdog input, battery freshness seal, and chip-enable gating. The Selector Guide below lists the specific functions available from each device. These devices offer two pretrimmed reset threshold voltages for ±5% or ±10% power supplies: 4.65V for the L versions and 4.40V for the M versions. The MAX817/ MAX818/MAX819 are available in space-saving µMAX packages, as well as 8-pin DIP/SO. ____________________________Features o Precision Supply-Voltage Monitor: 4.65V (MAX81_L) 4.40V (MAX81_M) o 11µA Quiescent Supply Current o 200ms Reset Time Delay o Watchdog Timer with 1.6sec Timeout (MAX817/MAX818) o Battery-Backup Power Switching; Battery Voltage Can Exceed VCC o Battery Freshness Seal o On-Board, 3ns Gating of Chip-Enable Signals (MAX818) o Uncommitted Voltage Monitor for Power-Fail or Low-Battery Warning (MAX817/MAX819) o Manual Reset Input (MAX819) MAX8...