Analog Devices Inc./Maxim Integrated MAX6387XS29D3+T

Overview

MAX6387XS29D3+T 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 VCC 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 MAX6387XS29D3+T datasheet, MAX6387XS29D3+T pinout, MAX6387XS29D3+T application, or MAX6387XS29D3+T equivalent, key selection criteria include its 2.93V fixed VCC threshold, 140ms reset timeout, auxiliary voltage monitoring capability via RESET IN, push-pull active-low output architecture, and 4-pin SC70 package compatibility with space-constrained designs.

Technical Context

The MAX6387XS29D3+T integrates two independent voltage comparators: one monitors VCC against a precision +2.93V threshold (±2.5% over temperature), while the other compares an external voltage at RESET IN to a +1.27V internal reference. Reset asserts when either comparator trips, and remains asserted for 140ms after recovery.

Its push-pull active-low RESET output drives directly without external pullup, supports sink currents up to 3.2mA at VCC ≥ 4.5V (VOL ≤ 0.4V), and maintains logic validity down to VCC = 1V. The RESET IN input features ±1nA leakage and 4.5μs propagation delay from threshold crossing to RESET assertion.

Key Specifications

Pinout & Package

MAX6387XS29D3+T is housed in a RoHS-compliant 4-pin SC70 package (outline 21-0098, land pattern 90-0187), measuring 2.0mm × 2.1mm × 0.95mm, suitable 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 MAX6387XS29D3+T, the μDFN variant offers better thermal handling but requires PCB redesign, while the TPS3808G33DBVR adds manual reset at the cost of higher current and loss of dual-supply capability - making MAX6387XS29D3+T optimal for compact, dual-rail, battery-sensitive designs.

Availability

MAX6387XS29D3+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, automotive body control units, and dual-rail FPGA configuration circuits requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6387XS29D3+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 demanding industrial, automotive, and computing applications, with emphasis on low-power, high-reliability solutions.

The MAX6381–MAX6390 family delivers ultra-low-power microprocessor supervisory circuits optimized for battery-operated equipment and multi-rail embedded systems requiring dual-voltage monitoring and guaranteed reset behavior across extreme temperatures.

FAQ

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

The MAX6387XS29D3+T has a factory-set VCC reset threshold of 2.93V (nominal), 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 on-chip references and BiCMOS process matching, ensuring consistent brownout detection without external calibration. The MAX6387XS29D3+T maintains this specification across all production lots and environmental conditions specified in the datasheet.

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

Yes, MAX6387XS29D3+T supports dual-voltage supervision via its dedicated RESET IN pin, which connects to an internal +1.27V comparator reference. To monitor a second rail, apply the target voltage through a resistor divider network to RESET IN so that the divided voltage equals +1.27V at the desired trip point. The MAX6387XS29D3+T asserts reset if either VCC falls below 2.93V or the voltage at RESET IN drops below +1.27V, enabling coordinated reset across multiple power domains.

What is the function and electrical behavior of the RESET output on MAX6387XS29D3+T?

The RESET output of MAX6387XS29D3+T is an active-low push-pull driver, meaning it actively pulls low during reset and actively drives high when deasserted - eliminating the need for an external pullup resistor. It sinks up to 3.2mA at VCC ≥ 4.5V (VOL ≤ 0.4V) and sources sufficient current to drive standard CMOS inputs. The MAX6387XS29D3+T guarantees correct logic state down to VCC = 1V, ensuring deterministic reset behavior even during severe brownout conditions.

How does the 140ms reset timeout period of MAX6387XS29D3+T impact system startup timing?

The 140ms minimum reset timeout of MAX6387XS29D3+T ensures the microprocessor remains held in reset long enough for all power rails to stabilize, clock circuits to lock, and internal registers to clear - meeting typical μP initialization requirements for ARM Cortex-M and RISC-V devices. This fixed timeout is internally generated and independent of external components, providing repeatable, jitter-free reset release timing. The MAX6387XS29D3+T guarantees this duration across voltage and temperature variations per the datasheet's tRP specification.

Is MAX6387XS29D3+T suitable for automotive applications, and what qualifications does it meet?

The MAX6387XS29D3+T is offered in an AEC-Q100 qualified version (denoted by /V suffix), tested to Grade 1 (–40°C to +125°C) for automotive body electronics applications. While the base MAX6387XS29D3+T is RoHS-compliant and operates across the same temperature range, the /V variant undergoes additional stress testing including HTOL, ESD, and mechanical shock validation. For automotive use, specify MAX6387XS29D3/V+T; the MAX6387XS29D3+T itself is rated for industrial applications but shares identical electrical performance and reliability characteristics.