+5V Microprocessor Supervisory Circuits

 

Part Number	Replacement	Explanation

Description

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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 V_CC. Other supervisory functions include active-low reset, backup-battery switchover, watchdog input, battery freshness seal, and chip-enable gating. The Selector Guide in the full data sheet 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.

MAX817L, M, MAX818L, M, MAX819L, M: Typical Operating Circuit Enlarge+

Key Features

• Precision Supply-Voltage Monitor:
• 4.65V (MAX81_L)
• 4.40V (MAX81_M)
• 11µA Quiescent Supply Current
• 200ms Reset Time Delay
• Watchdog Timer with 1.6sec Timeout (MAX817/MAX818)
• Battery-Backup Power Switching; Battery Voltage Can Exceed V_CC
• Battery Freshness Seal
• On-Board, 3ns Gating of Chip-Enable Signals (MAX818)
• Uncommitted Voltage Monitor for Power-Fail or Low-Battery Warning (MAX817/MAX819)
• Manual Reset Input (MAX819)

Applications/Uses

• Battery-Powered Computers/Controllers
• Critical µP Monitoring
• Embedded Controllers
• Intelligent Instruments
• Portable Equipment