Analog Devices Inc./Maxim Integrated MAX6386XS29D1+

Overview

MAX6386XS29D1+ from Maxim Integrated is a low-power microprocessor supervisory circuit with open-drain active-low reset output, factory-set 2.93V reset threshold (±2.5% over -40°C to +125°C), 140ms minimum VCC reset timeout, and debounced manual reset input (MR) featuring internal 63kΩ pullup. It monitors single supply voltage in portable/battery-powered systems requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6386XS29D1+ datasheet, MAX6386XS29D1+ pinout, MAX6386XS29D1+ application, or MAX6386XS29D1+ equivalent, key selection criteria include its 2.93V threshold accuracy, 140ms reset timeout, MR input compatibility with TTL/CMOS logic, guaranteed reset validity down to VCC = 1V, and SC70-4 package footprint for space-constrained designs.

Technical Context

The MAX6386XS29D1+ implements a precision bandgap-based voltage comparator with ±2.5% threshold accuracy across temperature, paired with a monolithic RC timer for deterministic 140ms reset assertion after VCC recovery. Its open-drain RESET output requires an external pullup and supports wired-OR configurations in multi-rail systems.

It integrates a debounced manual reset input (MR) with 1µs minimum pulse width support and 100ns glitch rejection, internally pulled up to VCC via 63kΩ resistor. The device operates from 1.0V to 5.5V supply and guarantees correct reset state down to VCC = 1V - critical for ultra-low-voltage brownout detection.

Key Specifications

Pinout & Package

MAX6386XS29D1+ is housed in a RoHS-compliant 4-pin SC70 package (package code X4+1), measuring 2.0mm × 2.1mm × 0.95mm, optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor reset applications.

Compared with MAX809TRD1+T, MAX6386XS29D1+ adds MR functionality in same 4-pin SC70 footprint; versus TPS3808G12DBVR, it offers lower quiescent current (3μA vs 8μA at 1.8V) and smaller package, but with looser threshold tolerance and fixed timing.

Availability

MAX6386XS29D1+ is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered data loggers, industrial PLC I/O modules, and automotive body control units requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6386XS29D1+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and computing applications.

The MAX6381–MAX6390 family delivers ultra-low-power, factory-trimmed supervisory circuits targeting space- and energy-constrained microprocessor systems requiring reliable reset generation under brownout, startup, and manual intervention conditions.

FAQ

What is the exact reset threshold voltage of MAX6386XS29D1+ and how stable is it over temperature?

The MAX6386XS29D1+ has a factory-set nominal reset threshold of 2.93V, with guaranteed accuracy of ±2.5% over the full operating temperature range of -40°C to +125°C. This stability is achieved via laser-trimmed on-chip resistors and a precision bandgap reference, ensuring consistent brownout detection without external calibration. The MAX6386XS29D1+ datasheet specifies worst-case deviation of ±73mV at temperature extremes.

Does MAX6386XS29D1+ require an external pullup resistor on the RESET pin, and what value is recommended?

Yes, MAX6386XS29D1+ features an open-drain active-low RESET output and requires an external pullup resistor to the host supply rail (e.g., 3.3V or 5V). A value between 10kΩ and 100kΩ is recommended: lower values improve rise time and noise immunity but increase static current; higher values minimize current draw but may slow edge transitions. For most 3.3V systems with short trace lengths, 47kΩ provides optimal balance. The MAX6386XS29D1+ itself draws zero current through this resistor when RESET is high.

Can the manual reset input (MR) of MAX6386XS29D1+ be left floating, or must it be terminated?

The MR pin of MAX6386XS29D1+ must not be left floating: it has an internal 63kΩ pullup resistor to VCC, but unconnected MR pins are susceptible to noise-induced false resets. Maxim recommends connecting MR to VCC through a 100kΩ resistor if unused, or directly to VCC for simplest implementation. For pushbutton use, connect a normally open switch from MR to GND with optional 0.1μF capacitor from MR to GND for enhanced noise immunity. Leaving MR unconnected risks spurious resets in noisy environments.

What is the minimum VCC voltage at which MAX6386XS29D1+ guarantees correct reset output behavior?

MAX6386XS29D1+ guarantees valid reset output logic state down to VCC = 1.0V - meaning the RESET pin will correctly assert low when VCC falls below 2.93V and deassert high after recovery, even as supply collapses. This specification ensures deterministic microprocessor behavior during deep brownout events where other supervisors may fail. Below 1.0V, reset state is not guaranteed; however, the MAX6386XS29D1+ continues to operate down to 1.0V, unlike many competitors that cease functioning below 1.2V.

Is MAX6386XS29D1+ pin-compatible with older Maxim reset ICs like MAX809 or MAX6326?

MAX6386XS29D1+ is not pin-compatible with MAX809 (SC70-3) or MAX6326 (SOT-23-3) due to its 4-pin SC70 package and inclusion of MR functionality. However, it is functionally compatible and pin-compatible within the MAX6384–MAX6390 family sharing the 4-pin SC70 footprint (e.g., MAX6384XS29D1+, MAX6385XS29D1+). For drop-in replacement of 3-pin parts, board redesign is required; Maxim explicitly lists MAX6386XS29D1+ as "pin compatible with MAX809/MAX810/..." only in functional grouping, not physical layout.