Analog Devices Inc./Maxim Integrated MAX6390XS34D4+T

Overview

MAX6390XS34D4+T from Maxim Integrated is a low-power microprocessor supervisory circuit with open-drain active-low reset output, factory-set 3.40V reset threshold (±2.5% over –40°C to +125°C), and dual timeout periods: 1120ms VCC reset timeout and 140ms manual reset timeout. It operates from 1.0V to 5.5V supply and consumes only 3μA at +1.8V, enabling reliable power monitoring in battery-powered embedded controllers.

For engineers reviewing the MAX6390XS34D4+T datasheet, MAX6390XS34D4+T pinout, MAX6390XS34D4+T application, or MAX6390XS34D4+T equivalent, key selection criteria include its 4-pin SC70 package, guaranteed reset validity down to VCC = 1V, open-drain output requiring external pullup, and distinct MR timeout (140ms) vs. VCC timeout (1120ms) timing behavior.

Technical Context

The MAX6390XS34D4+T implements a precision voltage comparator with ±2.5% threshold accuracy across temperature, paired with independent internal timers for VCC-initiated and MR-initiated reset assertion. Its reset logic asserts low on VCC drop below 3.40V or MR pull-down, holding for fixed timeout durations before deassertion.

Unlike push-pull variants, this device uses an open-drain RESET output requiring external pullup, ensuring compatibility with mixed-voltage systems and wired-OR configurations. The MR input features a low-value internal pullup resistor (500–3000Ω), optimized for fast release and noise immunity in manual reset applications.

Key Specifications

Pinout & Package

MAX6390XS34D4+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 MAX6326XR34D4+T and TPS3808G33DBVR, MAX6390XS34D4+T uniquely combines open-drain output, integrated MR with fast-release pullup, and asymmetric timeout periods - making it optimal for space-constrained, manually resettable systems requiring flexible reset bus architecture.

Availability

MAX6390XS34D4+T is available at Aetrix Electronics and suitable for industrial PLC controllers, battery-powered data loggers, automotive body control modules, and medical point-of-care devices requiring stable component supply and AEC-Q100–qualified performance.

Supply support for MAX6390XS34D4+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 industrial, automotive, and computing applications, with emphasis on low-power, high-reliability solutions.

The MAX6381–MAX6390 family delivers single-supply microprocessor supervisory circuits optimized for battery-sensitive and thermally demanding environments, featuring factory-trimmed thresholds, dual timeout options, and compact SC70/μDFN packaging.

FAQ

What is the exact reset threshold voltage of MAX6390XS34D4+T and how stable is it over temperature?

The MAX6390XS34D4+T has a factory-set nominal reset threshold of 3.40V, 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 resistors and a precision bandgap reference, eliminating the need for external calibration. The MAX6390XS34D4+T maintains this tolerance without drift, making it suitable for automotive and industrial applications where thermal cycling is common.

Does MAX6390XS34D4+T support manual reset, and what is the behavior of its MR pin?

Yes, MAX6390XS34D4+T includes a dedicated MR (manual reset) input that is active-low. When pulled low, it forces reset assertion for a fixed 140ms minimum timeout after release - independent of the 1120ms VCC timeout. The MR pin features an internal pullup resistor of 500–3000Ω, enabling direct connection to a momentary switch without external components. The MAX6390XS34D4+T also rejects glitches shorter than 100ns, ensuring noise immunity in harsh environments.

What package type and pin count does MAX6390XS34D4+T use, and is it RoHS-compliant?

MAX6390XS34D4+T is supplied in a 4-pin SC70 package (outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm, with lead(Pb)-free and RoHS-compliant construction indicated by the "+" suffix in the part number. This compact footprint supports high-density PCB layouts in portable and automotive electronics. The MAX6390XS34D4+T pinout is standardized across the MAX6384–MAX6390 SC70 variants, simplifying design reuse.

How does the open-drain RESET output of MAX6390XS34D4+T differ from push-pull alternatives?

The MAX6390XS34D4+T features an open-drain active-low RESET output, requiring an external pullup resistor to define the high-state voltage - enabling interoperability with mixed-voltage systems (e.g., 3.3V RESET bus driving a 5V-tolerant MCU input). Unlike push-pull outputs, it supports wired-OR configurations for multi-source reset arbitration. The MAX6390XS34D4+T sinks up to 3.2mA at VCC ≥ 4.5V, ensuring robust drive strength while maintaining compatibility with standard logic families.

What is the minimum supply voltage at which MAX6390XS34D4+T guarantees correct reset output behavior?

MAX6390XS34D4+T guarantees valid reset output logic states down to VCC = 1.0V - meaning the RESET pin remains correctly asserted or deasserted even during deep brownout conditions. This capability ensures reliable microprocessor initialization in low-voltage battery scenarios where other supervisors may fail. The MAX6390XS34D4+T achieves this via internal charge-pump-assisted biasing, and no external components are required to maintain functionality at 1V.