Maxim MAX6877 Power Supply User Manual


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Maxim > App Notes > MICROPROCESSOR SUPERVISOR CIRCUITS
Keywords: sequencing, sequencer, monitor, reset, voltage tracking, voltage tracker
Sep 20, 2006
APPLICATION NOTE 3918
User's Guide for the MAX6877 Power-Supply Tracker/Sequencer
Abstract: This application note is a step-by-step User's Guide for designing with the MAX6877 voltage tracker and
sequencer. The note explains how to make suitable component calculations.
Figure 1. The basic circuit for the MAX6877.
MAX6877 Overview
● Tracks or sequences up to three voltages
● Closed-loop tracking control with programmable slew rate
● Program thresholds with resistors
● Program slew rate and timing delays with capacitors
● Fault output and power-good output
Description
The MAX6877 voltage tracker/sequencer can track or sequence up to three voltages. Use the TRACK/SEQ pin to select
tracking or sequencing. The device will either track or sequence the three voltages, but it cannot track and sequence
simultaneously. Power-up begins when EN/active-low UV is asserted and all three input voltages are above their
thresholds. In the example circuit in Figure 1, EN/active-low UV is connected to the 12V bus, so the circuit will turn
on when the bus exceeds its threshold and turn off when it falls under its threshold.
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