MAX6838

Features:

`Factory-Set Reset Threshold Voltages for Nominal Supplies from 1.2V to 1.8V
`Low Power Consumption: 7.5µA (typ)
`Space-Saving 3- and 4-Pin SC70 Packages
`±2.5% Reset Threshold Accuracy Over Temperature
`Five Different Timeout Periods Available: 70µs (voltage detector), 1.5ms, 30ms, 210ms, and 1.68s
`Three Reset Output Configurations Push-Pull RESET Push-Pull RESET Open-Drain RESET
`Guaranteed Reset Valid to V<sub>CC</sub> = 0.55V-Active-Low 0.75V-Active-High
`Adjustable Threshold Reset-In Option
`Manual Reset Input Option
`Immune to Short Negative VCC Transients
`Pin Compatible with MAX803/MAX809/MAX810, MAX6711/MAX6712/MAX6713, and MAX6381MAX6390 Series


Application

·Computers
·Controllers
·Intelligent Instruments
·Critical µP and µC Power Monitoring
·Portable/Battery-Powered Equipment


Pinout




Specifications

V_CC.............................................................................................-0.3V to +6.0V
Open-Drain RESET, MR ...............................................................-0.3V to +6.0V
RESET-IN, Push-Pull RESET and RESET .............................-0.3V to (V_CC + 0.3V)
Input/Output Current (all pins) .................................................................20mA
3-Pin SC70 (derate 2.9mW/°C above +70°C)......................................235mW
4-Pin SC70 (derate 3.1mW/°C above +70°C)......................................245mW
Operating Temperature Range ...............................................-40°C to +85°C
Junction Temperature............................................................................+150°C
Storage Temperature Range .................................................-65°C to +150°C
Lead Temperature (soldering, 10s) .......................................................+300°C


Description

The MAX6838 are microprocessor (µP) supervisory circuits used to monitor low-voltage power supplies in µP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +1.2V to +1.8V powered circuits.

These MAX6838 assert a reset signal whenever the V_CC supply voltage declines below a preset threshold or whenever manual reset (MR) is asserted. Reset remains asserted for a fixed timeout delay after V_CC has risen above the reset threshold or when manual reset is deasserted. Five different timeout periods of MAX6838 are available: 70µs (voltage detector), 1.5ms, 30ms, 210ms, and 1.68s. Reset thresholds suitable for operation with a variety of supply voltages are available.

The MAX6832/MAX6835/MAX6838 have a push-pull active-low reset output (RESET ). The MAX6833/ MAX6836/MAX6839 have a push-pull active-high reset output (RESET ) and the MAX6834/MAX6837/MAX6840 have an open-drain active-low reset output (RESET ). The open-drain active-low reset output requires a pullup resistor that can be connected to a voltage higher than V_CC.

The MAX6835/MAX6836/MAX6837 feature a debounced manual reset input (MR ), while the MAX6838/MAX6839/ MAX6840 provide a RESET-IN input allowing the user to externally adjust the reset threshold. The reset comparator is designed to ignore fast transients on V_CC.

Low supply current of 7.5µA makes the MAX6838 ideal for use in portable equipment. These devices are available in 3- and 4-pin SC70 packages.