Analog Devices Inc./Maxim Integrated MAX6387XS26D3+T

Overview

MAX6387XS26D3+T from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with active-low push-pull reset output, factory-set 2.63V 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 output down to VCC = 1V - used in battery-powered instrumentation and dual-rail embedded systems requiring reliable power-up sequencing.

For engineers reviewing the MAX6387XS26D3+T datasheet, MAX6387XS26D3+T pinout, MAX6387XS26D3+T application, or MAX6387XS26D3+T equivalent, key selection criteria include its 2.63V reset threshold accuracy, 140ms timeout, 4-pin SC70 package, dual-supply monitoring capability via RESET IN, and compatibility with low-voltage core/I/O rail architectures.

Technical Context

The MAX6387XS26D3+T integrates two independent voltage comparators: one monitors VCC against a precision 2.63V internal reference, while the other compares an external voltage applied to RESET IN against a fixed 1.27V internal reference. Reset asserts if either monitored voltage falls below its respective threshold.

It features a monolithic timer that holds the active-low push-pull RESET output asserted for ≥140ms after VCC or RESET IN recovers above threshold. The device operates across 1.0V–5.5V supply range and maintains guaranteed logic state on RESET down to VCC = 1V - critical for brownout resilience in portable systems.

Key Specifications

Pinout & Package

MAX6387XS26D3+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 - optimized for space-constrained portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6387LT26D3+T, the MAX6387XS26D3+T offers superior board-area efficiency and lower thermal resistance in SC70, while MAX6389XS26D3+T trades push-pull convenience for bus flexibility - making the XS26D3+T optimal for compact, single-load reset applications.

Availability

MAX6387XS26D3+T is available at Aetrix Electronics and suitable for battery-powered medical sensors, dual-rail industrial controllers, automotive body modules, and portable test equipment requiring stable component supply with guaranteed long-term manufacturability.

Supply support for MAX6387XS26D3+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, sensing, and connectivity applications - with emphasis on low-power, high-reliability solutions for harsh environments.

The MAX6381–MAX6390 family delivers single/dual low-voltage μP reset circuits targeting space- and power-constrained embedded systems where deterministic power-on reset and brownout protection are mission-critical.

FAQ

What is the exact reset threshold voltage of MAX6387XS26D3+T and how stable is it over temperature?

The MAX6387XS26D3+T has a factory-set nominal VCC reset threshold of 2.63V, with guaranteed accuracy of ±2.5% across the full operating temperature range of -40°C to +125°C. This corresponds to a min/max threshold window of 2.56V to 2.69V at temperature extremes. The device achieves this stability using laser-trimmed references and a BiCMOS process with low tempco design - eliminating need for external calibration in production systems.

Does MAX6387XS26D3+T support monitoring of a second voltage rail, and how is it implemented?

Yes, MAX6387XS26D3+T supports dual-rail supervision via its dedicated RESET IN pin. This pin connects to an internal 1.27V comparator reference; applying an external voltage - typically set by a resistor divider from a secondary supply - allows user-defined reset triggering. For example, connecting a 1.2V core rail through a matched divider yields precise 1.2V supervision. Input leakage is ≤50nA, enabling use of high-value resistors without accuracy loss.

What is the function of the RESET output on MAX6387XS26D3+T, and what load can it drive?

The RESET output of MAX6387XS26D3+T is an active-low push-pull driver, meaning it actively pulls low during reset and actively drives high when deasserted - requiring no external pullup. It can sink up to 3.2mA at VCC ≥ 4.5V (VOL ≤ 0.4V) and source sufficient current to drive standard CMOS/TTL reset inputs. This architecture ensures fast, robust reset signaling without passive components or timing uncertainty from RC networks.

How does the 140ms reset timeout period of MAX6387XS26D3+T benefit system design?

The 140ms minimum reset timeout of MAX6387XS26D3+T ensures the microcontroller or FPGA remains held in reset long enough for all internal power domains to stabilize, clocks to lock, and configuration memory to load - especially critical for modern low-voltage SoCs with complex power sequencing. Unlike shorter timeouts, this value accommodates worst-case ramp times of 1.0V–1.2V cores and eliminates need for external timing components or software workarounds.

Is MAX6387XS26D3+T compatible with AEC-Q100 automotive requirements?

The MAX6387XS26D3+T itself is not automotive-qualified; however, the MAX6387XS26D3/V+T variant (with /V suffix) is AEC-Q100 qualified for Grade 1 (-40°C to +125°C). The +T suffix indicates tape-and-reel packaging, and the RoHS-compliant SC70 package meets automotive assembly standards. For automotive applications, specify the /V version - the electrical and functional behavior of MAX6387XS26D3+T and MAX6387XS26D3/V+T is identical except for qualification testing and traceability documentation.