Analog Devices Inc./Maxim Integrated MAX6389XS20D1-T

Overview

MAX6389XS20D1-T from Maxim Integrated is a low-power microprocessor supervisory circuit with open-drain active-low reset output, factory-set 2.0V reset threshold (±2.5% over −40°C to +125°C), 1ms minimum reset timeout, and auxiliary RESET IN input for dual-voltage monitoring. It operates from 1.0V to 5.5V supply and consumes only 3μA at 1.8V, targeting battery-powered embedded systems requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6389XS20D1-T datasheet, MAX6389XS20D1-T pinout, MAX6389XS20D1-T application, or MAX6389XS20D1-T equivalent, key selection criteria include its 2.0V V_TH, 1ms t_RP, open-drain output architecture, RESET IN comparator compatibility, and 4-pin SC70 package - all critical for space-constrained, dual-rail power monitoring in portable instrumentation and industrial controllers.

Technical Context

The MAX6389XS20D1-T integrates a precision voltage comparator referenced to an internal 1.27V bandgap for the RESET IN input, enabling user-configurable secondary reset thresholds via external resistor dividers. Its primary V_CC monitor uses a factory-trimmed threshold with ±2.5% accuracy across temperature and 60ppm/°C tempco.

Reset assertion occurs on V_CC fall below 2.0V or RESET IN fall below 1.27V, with guaranteed valid reset state down to V_CC = 1.0V. The 1ms minimum timeout is generated by an internal RC timer, immune to negative-going V_CC transients up to 100mV overdrive for durations under ~35µs.

Key Specifications

Pinout & Package

MAX6389XS20D1-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 high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6389XS20D1-T, MAX6389XS20D2-T extends reset hold time for slower peripherals but sacrifices fast-response capability, while TLV803EB20DBZR reduces supply current by 40% but removes dual-voltage supervision - making MAX6389XS20D1-T uniquely suited for compact, battery-operated dual-rail systems needing 1ms timing precision.

Availability

MAX6389XS20D1-T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, automotive body control units, and smart energy meters requiring stable component supply with AEC-Q100-aligned reliability.

Supply support for MAX6389XS20D1-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, emphasizing low power, high reliability, and small form factor.

The MAX6381–MAX6390 family delivers single/dual low-voltage supervisory circuits targeting space-constrained, battery-powered systems where guaranteed reset behavior across wide temperature ranges and supply voltages is critical.

FAQ

What is the exact reset threshold voltage and tolerance for MAX6389XS20D1-T?

The MAX6389XS20D1-T has a factory-set reset threshold of 2.00V with ±2.5% accuracy over the full operating temperature range of −40°C to +125°C. This specification is guaranteed by design and applies to both V_CC monitoring and the internal reference used for the RESET IN comparator. The MAX6389XS20D1-T achieves this stability via laser-trimmed BiCMOS process technology, ensuring consistent performance without external calibration.

Does MAX6389XS20D1-T support monitoring of two independent power rails?

Yes, the MAX6389XS20D1-T supports dual-rail supervision: its V_CC pin monitors the primary supply (2.0V threshold), while the dedicated RESET IN pin compares an external voltage against an internal 1.27V reference. By connecting a resistor divider to RESET IN, users can set a custom threshold for a second rail - for example, configuring a 5V rail to trigger reset at 4.75V. This dual-monitoring capability is intrinsic to the MAX6389XS20D1-T and requires no additional components beyond the divider resistors.

What is the function and electrical behavior of the RESET output on MAX6389XS20D1-T?

The RESET output of the MAX6389XS20D1-T is an open-drain, active-low signal that pulls low when V_CC falls below 2.0V or RESET IN falls below 1.27V, and remains low for the full 1ms reset timeout period after recovery. It requires an external pullup resistor (typically 10kΩ to V_CC) and can sink up to 3.2mA at V_CC ≥ 4.5V. This architecture enables wired-OR reset buses and level-shifting - a key feature distinguishing the MAX6389XS20D1-T from push-pull alternatives.

Can MAX6389XS20D1-T operate reliably during deep brownout conditions?

Yes, the MAX6389XS20D1-T guarantees valid reset output state down to V_CC = 1.0V, meaning it continues to assert or deassert RESET correctly even as the supply collapses. This is achieved through proprietary low-voltage biasing and comparator design. Unlike many supervisors that become indeterminate below 1.5V, the MAX6389XS20D1-T maintains functional integrity through the entire brownout event - a critical requirement for safe shutdown in battery-powered systems where V_CC may dip to 1.0V before cutoff.

What package type and dimensions does MAX6389XS20D1-T use?

The MAX6389XS20D1-T is supplied in a 4-pin SC70 package (outline 21-0098) measuring 2.0mm × 2.1mm × 0.95mm with a 0.65mm pin pitch. It features RoHS-compliant matte-tin lead finish and thermal characteristics of θ_JA = 322.6°C/W on a multilayer board. This compact, surface-mount package enables high-density layouts in portable electronics - a defining physical attribute of the MAX6389XS20D1-T that directly impacts PCB area and thermal management decisions.