Analog Devices Inc./Maxim Integrated MAX6387XS29D3+

Overview

MAX6387XS29D3+ from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with active-low push-pull reset output, factory-set 2.93V VCC reset threshold (±2.5% over –40°C to +125°C), 140ms minimum reset timeout, and auxiliary RESET IN input for monitoring a second voltage source. It consumes only 3µA at +1.8V and guarantees valid reset state down to VCC = 1V, used in portable battery-powered equipment and dual-voltage systems requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6387XS29D3+ datasheet, MAX6387XS29D3+ pinout, MAX6387XS29D3+ application, or MAX6387XS29D3+ equivalent, key selection criteria include its dual-monitoring capability (VCC + RESET IN), precise 2.93V threshold, 140ms timeout, SC70-4 package footprint, and compatibility with low-power µP-based embedded control systems.

Technical Context

The MAX6387XS29D3+ integrates two independent voltage comparators: one monitors VCC against a factory-trimmed 2.93V threshold with ±2.5% accuracy across –40°C to +125°C, and the other compares an external voltage at RESET IN to a stable +1.27V internal reference. Its reset assertion logic triggers when either monitored voltage falls below its respective threshold.

It features a precision internal timer that holds the active-low push-pull RESET output asserted for exactly 140ms (minimum) after VCC or RESET IN recovers above threshold. The device operates from 1.0V to 5.5V supply and maintains guaranteed reset output validity down to VCC = 1V - critical for low-voltage brownout detection in modern SoC and MCU power domains.

Key Specifications

Pinout & Package

MAX6387XS29D3+ is housed in a lead-free 4-pin SC70 package (X4-1), measuring 1.0mm × 1.25mm × 0.75mm, optimized for space-constrained portable and wearable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6387XS29D3+, the LT variant offers identical functionality in a thermally superior package ideal for dense layouts, while TPS3808G33DBVR trades dual-monitoring capability for ultra-low current - making MAX6387XS29D3+ the optimal choice when secondary rail supervision is required in minimal area.

Availability

MAX6387XS29D3+ is available at Aetrix Electronics and suitable for portable/battery-powered equipment, dual-voltage systems, and critical µP and µC applications requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6387XS29D3+ 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 and mixed-signal ICs for power, sensing, and connectivity applications in industrial, automotive, and computing markets.

The MAX6381–MAX6390 family delivers low-power, high-accuracy µP supervisory circuits targeting space- and energy-constrained embedded systems needing dual-rail monitoring and guaranteed reset behavior across extreme temperatures.

FAQ

What is the exact reset threshold voltage for MAX6387XS29D3+ and how stable is it over temperature?

The MAX6387XS29D3+ has a factory-set VCC reset threshold of 2.93V, with a guaranteed range of 2.85V (min) to 3.00V (max) over the full operating temperature range of –40°C to +125°C. Its threshold accuracy is ±2.5%, and its tempco is 60ppm/°C - meaning total drift across temperature is less than 20mV, ensuring consistent brownout detection in automotive and industrial environments where MAX6387XS29D3+ is deployed.

Does MAX6387XS29D3+ support monitoring of a second voltage rail, and how is it implemented?

Yes, MAX6387XS29D3+ supports secondary voltage monitoring via its dedicated RESET IN pin, which compares an external voltage to a precise +1.27V internal reference. To configure it for a target threshold (e.g., 2.5V), connect a resistor divider (R1/R2) to RESET IN using R1 = R2 × [(V_INTH/1.27V) – 1]. The input leakage is ≤±1nA, enabling use of high-value resistors without accuracy loss - a key feature distinguishing MAX6387XS29D3+ from single-rail supervisors.

What is the function of the RESET output on MAX6387XS29D3+, and what drive strength does it provide?

The RESET output of MAX6387XS29D3+ is an active-low push-pull driver, meaning it actively pulls low during reset assertion and actively drives high when deasserted - no external pull-up is needed. At VCC ≥ 2.5V and ISINK = 1.2mA, VOL is guaranteed ≤0.3V; at VCC ≥ 4.5V and ISOURCE = 3.2mA, VOH is ≥0.8×VCC. This robust drive capability ensures reliable interfacing with diverse µP reset inputs without signal integrity concerns in MAX6387XS29D3+ designs.

Can MAX6387XS29D3+ operate reliably during severe supply voltage droop, and down to what VCC level does it guarantee correct reset behavior?

Yes, MAX6387XS29D3+ guarantees correct reset output logic state down to VCC = 1.0V - well below typical µP minimum operating voltages. This ensures deterministic behavior during deep brownout events where VCC collapses gradually. Unlike many supervisors that lose functionality near 1.5V, MAX6387XS29D3+ continues asserting reset until VCC reaches 1V, then holds last valid state, preventing spurious release that could crash the system - a critical reliability feature confirmed in MAX6387XS29D3+ characterization data.

What package type and dimensions does MAX6387XS29D3+ use, and is it RoHS-compliant?

MAX6387XS29D3+ is supplied in a lead-free 4-pin SC70 package (X4-1), with body dimensions of 1.0mm × 1.25mm × 0.75mm and a standard 0.65mm pin pitch. The "+" suffix explicitly denotes RoHS-compliant, halogen-free construction per JEDEC J-STD-020. This compact, thermally efficient package supports high-density layouts in wearables, hearing aids, and other miniaturized electronics where MAX6387XS29D3+ is commonly applied.