Analog Devices Inc./Maxim Integrated MAX6387XS28D2+T

Overview

MAX6387XS28D2+T from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with active-low push-pull reset output, factory-set 2.80V VCC reset threshold (±2.5% over –40°C to +125°C), 20ms 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 battery-powered instrumentation and dual-rail embedded systems.

For engineers reviewing the MAX6387XS28D2+T datasheet, MAX6387XS28D2+T pinout, MAX6387XS28D2+T application, or MAX6387XS28D2+T equivalent, key selection criteria include its 2.80V reset threshold accuracy, 20ms VCC timeout, 4-pin SC70 package, auxiliary voltage monitoring capability, and compatibility with dual-supply microcontroller power domains requiring independent brownout detection.

Technical Context

The MAX6387XS28D2+T integrates two independent reset comparators: one monitors VCC against a precision 2.80V internal threshold, while the second compares an external voltage applied to RESET IN against a stable +1.27V reference. Reset asserts when either input falls below its respective threshold, and remains asserted for exactly 20ms after recovery.

Its auxiliary RESET IN input accepts high-impedance signals (leakage ±1nA) and supports user-defined thresholds via external resistor dividers; the device guarantees correct reset logic state across full VCC range (1.0V–5.5V) and operates reliably from –40°C to +125°C without requiring external components beyond a pullup for open-drain variants (not applicable here).

Key Specifications

Pinout & Package

MAX6387XS28D2+T is housed in a RoHS-compliant 4-pin SC70 package (outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm, with thermal resistance θ_JA = 322.6°C/W on multilayer board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6387XS28D2+T, the LT28D2 variant offers identical functionality in a thermally superior μDFN package but occupies more board area, while the TPS3808G125DBVR provides lower-cost single-rail supervision at the expense of missing the integrated auxiliary voltage monitor essential for true dual-supply coordination.

Availability

MAX6387XS28D2+T is available at Aetrix Electronics and suitable for industrial sensor nodes, battery-powered data loggers, dual-rail microcontroller systems, and automotive body control modules requiring stable component supply and long-term lifecycle support.

Supply support for MAX6387XS28D2+T 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 management, sensing, and interface applications in industrial, automotive, and computing markets.

The MAX6381–MAX6390 family delivers ultra-low-power, high-accuracy voltage supervision for microprocessor-based systems where reliable power-up sequencing and brownout protection are mission-critical.

FAQ

What is the exact reset threshold voltage of MAX6387XS28D2+T and how stable is it over temperature?

The MAX6387XS28D2+T has a factory-set nominal VCC reset threshold of 2.80V, with guaranteed accuracy of ±2.5% over the full operating temperature range of –40°C to +125°C. This stability is achieved through laser-trimmed internal references and BiCMOS process design, eliminating the need for external calibration. The MAX6387XS28D2+T maintains this tolerance without derating or additional compensation circuits.

Does MAX6387XS28D2+T support monitoring of a second voltage rail, and how is it implemented?

Yes, MAX6387XS28D2+T includes a dedicated RESET IN input that compares an external voltage to an internal +1.27V reference. To monitor a second rail (e.g., 3.3V), connect it to RESET IN through a resistor divider configured so that the divided voltage equals 1.27V at the desired trip point. The MAX6387XS28D2+T asserts reset if either VCC drops below 2.80V or the voltage at RESET IN falls below 1.27V.

What is the reset timeout duration for MAX6387XS28D2+T and is it adjustable?

The MAX6387XS28D2+T provides a fixed minimum reset timeout of 20ms after VCC or RESET IN recovers above their respective thresholds. This value is factory-programmed and not user-adjustable; it corresponds to the "D2" suffix in the part number. The timeout is guaranteed over temperature and supply voltage, ensuring consistent microprocessor initialization timing without external timing components.

What package type and pin count does MAX6387XS28D2+T use, and are there alternative packages?

MAX6387XS28D2+T uses a 4-pin SC70 package (outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm, with RoHS-compliant lead-free finish. An alternative package is the 6-pin μDFN (L611+1) version, designated MAX6387LT28D2+T, which shares identical electrical specifications but offers improved thermal performance (θ_JA = 477°C/W) and larger PCB footprint.

Can MAX6387XS28D2+T operate reliably at very low supply voltages, and what is its minimum functional VCC?

Yes, MAX6387XS28D2+T guarantees correct reset output logic state down to VCC = 1.0V, enabling robust operation during deep brownout conditions typical in lithium battery discharge profiles. Its internal circuitry remains fully functional across the full 1.0V–5.5V operating range, and the reset output remains valid and noise-immune even as VCC approaches 1V - a key differentiator from many competing supervisors.