Analog Devices Inc./Maxim Integrated MAX6389XS31D3-T

Overview

MAX6389XS31D3-T from Maxim Integrated is a low-power, open-drain active-low microprocessor supervisory circuit designed for dual-voltage system monitoring. It features a factory-set 3.08V reset threshold (±2.5% over -40°C to +125°C), 140ms minimum VCC reset timeout, and auxiliary RESET IN input for secondary voltage monitoring. It operates from 1.0V to 5.5V supply and consumes only 3μA at 1.8V - ideal for battery-powered instrumentation and automotive control modules.

For engineers reviewing the MAX6389XS31D3-T datasheet, MAX6389XS31D3-T pinout, MAX6389XS31D3-T application, or MAX6389XS31D3-T equivalent, key selection criteria include its open-drain active-low reset output with guaranteed valid state down to VCC = 1V, ±2.5% threshold accuracy across temperature, 140ms reset timeout, and dedicated RESET IN comparator referenced to 1.27V for user-adjustable secondary monitoring.

Technical Context

The MAX6389XS31D3-T integrates a precision bandgap reference and comparator for VCC monitoring plus a separate high-impedance RESET IN input compared against an internal 1.27V reference. Its reset assertion logic triggers when either VCC falls below 3.08V or RESET IN drops below its derived threshold (e.g., via external resistor divider), with independent timing control.

It uses BiCMOS process technology to achieve ultra-low quiescent current (3μA at 1.8V) while maintaining robust negative-going transient immunity and guaranteed reset validity down to VCC = 1V - enabling reliable brownout detection in low-voltage embedded systems without external support circuitry.

Key Specifications

Pinout & Package

MAX6389XS31D3-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 PCB layouts in portable and automotive electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6389XS31D3-T, MAX6387XS31D3-T offers identical electrical supervision but in a thermally superior μDFN package, while TPS3808G33DBVR provides higher threshold accuracy at the cost of losing dual-voltage capability - making MAX6389XS31D3-T optimal for compact, dual-rail, low-power designs.

Availability

MAX6389XS31D3-T is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, portable medical glucose meters, and battery-powered smart sensor nodes requiring stable component supply and long-term lifecycle support.

Supply support for MAX6389XS31D3-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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications applications.

The MAX6381–MAX6390 family was engineered for low-power, dual-voltage microprocessor supervision in space- and energy-constrained systems - emphasizing precision threshold accuracy, ultra-low quiescent current, and robust transient immunity.

FAQ

What is the exact reset threshold voltage of MAX6389XS31D3-T and how stable is it over temperature?

The MAX6389XS31D3-T has a factory-set nominal reset threshold of 3.08V, 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 internal resistors and a precision bandgap reference, eliminating the need for external calibration in automotive and industrial applications where thermal drift must be minimized.

Does MAX6389XS31D3-T support monitoring of a second voltage rail, and how is it implemented?

Yes, MAX6389XS31D3-T supports secondary voltage monitoring via its dedicated RESET IN pin, which compares the applied voltage against an internal 1.27V reference. To monitor a second rail (e.g., 3.3V), connect it to RESET IN through a resistor divider - for example, R1 = 162kΩ and R2 = 100kΩ yields a 2.08V threshold. The input leakage is ≤±1nA, ensuring minimal error from divider loading.

What is the function of the open-drain RESET output in MAX6389XS31D3-T, and what pullup value is recommended?

The open-drain RESET output in MAX6389XS31D3-T allows wired-OR connection with other reset sources and level translation across voltage domains. An external pullup resistor is mandatory; 10kΩ to 100kΩ is typical. At VCC ≥ 4.5V and ISINK = 3.2mA, VOL ≤ 0.4V ensures solid logic-low assertion. Lower values improve noise immunity but increase static current - 47kΩ balances speed and power in most 3.3V systems.

How does MAX6389XS31D3-T handle power supply transients, and what protection does it offer against false resets?

MAX6389XS31D3-T incorporates inherent immunity to short-duration negative-going VCC transients (glitches). Its reset comparator requires sustained overdrive - e.g., a 100mV drop below threshold must persist >35µs to trigger reset. This prevents spurious resets from ESD events or switching noise. Adding a 0.1µF ceramic capacitor near the VCC pin further enhances immunity per the datasheet recommendation.

Is MAX6389XS31D3-T qualified for automotive applications, and what evidence supports this claim?

MAX6389XS31D3-T carries the "/V" suffix in its ordering information (e.g., MAX6389XS31D3/V+T), indicating AEC-Q100 qualification. The device meets Grade 1 temperature requirements (-40°C to +125°C), undergoes stress testing per AEC-Q100 Rev H, and is manufactured in an IATF 16949-certified facility - confirmed in Maxim's official ordering guide and package documentation.