Analog Devices Inc./Maxim Integrated MAX6389XS16D3

Overview

MAX6389XS16D3 from Maxim Integrated is a low-power, open-drain active-low microprocessor supervisory circuit with factory-set 1.58V reset threshold, 140ms minimum reset timeout, and auxiliary RESET IN input for dual-voltage monitoring. It operates from 1.0V to 5.5V supply, consumes only 3µA at +1.8V, and guarantees valid reset output down to VCC = 1V. It is used in portable battery-powered equipment requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6389XS16D3 datasheet, MAX6389XS16D3 pinout, MAX6389XS16D3 application, or MAX6389XS16D3 equivalent, key selection considerations include its 1.58V ±2.5% threshold accuracy over –40°C to +125°C, open-drain output requiring external pull-up, RESET IN comparator referenced to +1.27V, and immunity to negative-going VCC transients up to 35µs at 100mV overdrive.

Technical Context

The MAX6389XS16D3 integrates a precision voltage comparator with ±2.5% threshold accuracy over temperature and a programmable reset timeout timer. Its RESET IN input connects to an internal +1.27V reference, enabling user-adjustable secondary voltage monitoring via external resistor divider.

It features open-drain active-low RESET output with guaranteed VOL ≤ 0.3V at ISINK = 80µA and VCC ≥ 1.0V, and supports operation down to VCC = 1V while maintaining correct logic state - critical for low-voltage brownout detection in modern embedded systems.

Key Specifications

Pinout & Package

MAX6389XS16D3 is housed in a lead-free 4-pin SC70 package (X4-1), measuring 1.0mm × 1.0mm × 0.5mm, suitable for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6389XS16D3, the MAX6389LT16D3 offers identical functionality in a thermally superior µDFN package, while the TPS3808G15DBVR trades dual-monitoring capability for improved threshold precision and push-pull drive - making MAX6389XS16D3 uniquely suited for compact, dual-rail, ultra-low-power applications.

Availability

MAX6389XS16D3 is available at Aetrix Electronics and suitable for portable medical sensors, industrial IoT edge nodes, automotive body control modules, and smart energy meters requiring stable component supply and long-term lifecycle support.

Supply support for MAX6389XS16D3 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, communications, and computing markets.

The MAX6381–MAX6390 family was designed specifically for low-voltage, low-power microprocessor reset supervision in battery-operated and space-constrained systems - emphasizing accuracy, ultra-low quiescent current, and flexible dual-rail monitoring.

FAQ

What is the factory-set reset threshold voltage for MAX6389XS16D3?

The MAX6389XS16D3 has a factory-set reset threshold of 1.58V, with ±2.5% accuracy over the full operating temperature range of –40°C to +125°C. This value is confirmed in the Reset Thresholds table of the datasheet (suffix "16") and is laser-trimmed during production. The MAX6389XS16D3 uses this fixed threshold to monitor VCC and initiate reset when supply voltage falls below 1.58V.

Does MAX6389XS16D3 support monitoring of a second voltage rail?

Yes, the MAX6389XS16D3 supports dual-voltage supervision via its dedicated RESET IN pin, which connects to an internal +1.27V reference comparator. When an external resistor divider applies a scaled version of a secondary rail to RESET IN, the MAX6389XS16D3 asserts reset if that rail falls below its calculated threshold - enabling coordinated reset across multiple power domains without additional ICs.

What is the reset timeout period of MAX6389XS16D3 and how is it configured?

The MAX6389XS16D3 has a fixed minimum reset timeout period of 140ms, indicated by the "D3" suffix in its part number. This timeout is internally generated and non-adjustable. After VCC rises above the 1.58V threshold, the MAX6389XS16D3 holds the open-drain RESET output low for at least 140ms to ensure complete µP initialization - a value selected to meet typical bootloader timing requirements.

What package type and dimensions does MAX6389XS16D3 use?

The MAX6389XS16D3 is packaged in a lead-free 4-pin SC70 (X4-1) package measuring 1.0mm × 1.0mm × 0.5mm. Pin 1 is VCC, Pin 2 is GND, Pin 3 is RESET IN, and Pin 4 is RESET. This ultra-compact outline is documented in Maxim's package drawing 21-0098 and is optimized for high-density portable PCB layouts.

Can MAX6389XS16D3 operate reliably at very low supply voltages?

Yes, the MAX6389XS16D3 guarantees correct RESET output logic state down to VCC = 1.0V, as specified in its Absolute Maximum Ratings and Electrical Characteristics tables. This ensures fail-safe operation during deep brownout events. However, its open-drain RESET output requires an external pull-up resistor to function correctly below ~1.8V, since internal drive capability diminishes at ultra-low VCC.