Analog Devices Inc./Maxim Integrated MAX6389XS23D3-T

Overview

MAX6389XS23D3-T from Maxim Integrated is a low-power microprocessor supervisory circuit with open-drain active-low reset output, factory-set 2.31V VCC reset threshold (±2.5% over –40°C to +125°C), 140ms 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, serving in battery-powered instrumentation and embedded controllers requiring reliable brownout detection.

For engineers reviewing the MAX6389XS23D3-T datasheet, MAX6389XS23D3-T pinout, MAX6389XS23D3-T application, or MAX6389XS23D3-T equivalent, key selection criteria include its 2.31V reset threshold accuracy, 140ms timeout, open-drain output requiring external pullup, RESET IN comparator referenced to 1.27V, and guaranteed valid reset state down to VCC = 1V.

Technical Context

The MAX6389XS23D3-T integrates a precision voltage comparator for VCC monitoring and a separate high-impedance RESET IN comparator referenced to an internal 1.27V bandgap. Reset asserts when either VCC falls below 2.31V or RESET IN drops below its user-defined threshold (set via external resistor divider), with propagation delay under 4.5µs across temperature.

Its open-drain RESET output supports wired-OR configurations and level-shifting, while the device guarantees correct logic state down to VCC = 1V - enabling robust operation during deep brownout. The 140ms reset timeout is generated by an internal RC timer with ±20% tolerance, normalized to ±1.5% variation over temperature.

Key Specifications

Pinout & Package

MAX6389XS23D3-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, 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 MAX6389XS23D3-T, the μDFN variant offers better thermal dissipation but requires PCB redesign, while the TPS3808G33DBVR sacrifices dual-monitoring flexibility and adjustable timing for lower unit cost in fixed-threshold designs.

Availability

MAX6389XS23D3-T is available at Aetrix Electronics and suitable for industrial sensor nodes, battery-powered data loggers, automotive body control modules, and medical point-of-care devices requiring stable component supply and long-term production continuity.

Supply support for MAX6389XS23D3-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 interface applications, with emphasis on low-power, high-reliability solutions for industrial and automotive markets.

The MAX6381–MAX6390 family delivers ultra-low-power microprocessor supervisory circuits optimized for battery longevity and dual-rail fault detection in space-constrained embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6389XS23D3-T and how stable is it over temperature?

The MAX6389XS23D3-T has a factory-set nominal VCC reset threshold of 2.31V, with guaranteed accuracy of ±2.5% over the full operating temperature range of –40°C to +125°C. This stability is achieved using a trimmed bandgap reference and low-drift comparator design, ensuring consistent brownout detection in automotive and industrial environments where ambient temperature varies widely. The MAX6389XS23D3-T maintains this specification without external calibration.

Does MAX6389XS23D3-T support monitoring of a second voltage rail, and how is it implemented?

Yes, MAX6389XS23D3-T supports dual-voltage monitoring via its dedicated RESET IN pin, which connects to an internal comparator referenced to a precise 1.27V bandgap. To monitor a second rail (e.g., 2.5V or 3.3V), users configure an external resistor divider between that rail and ground, connecting the midpoint to RESET IN. The MAX6389XS23D3-T asserts reset if either VCC falls below 2.31V or the divided voltage at RESET IN drops below 1.27V - enabling independent supervision of core and I/O supplies.

What is the function of the open-drain RESET output in MAX6389XS23D3-T, and what external component is required?

MAX6389XS23D3-T features an open-drain active-low RESET output, meaning it can only sink current to pull the line low and requires an external pullup resistor to establish a high logic level. A typical value is 10kΩ to 100kΩ connected between RESET and the target logic supply (e.g., 3.3V). This configuration allows wired-OR connection with other reset sources and level translation across different voltage domains - a key advantage over push-pull outputs in multi-supply systems.

How does MAX6389XS23D3-T behave during deep brownout conditions where VCC drops below 1.0V?

MAX6389XS23D3-T guarantees correct RESET output logic state down to VCC = 1.0V, meaning it will assert or deassert reset predictably even as supply voltage collapses. However, below 1.0V, internal circuitry cannot maintain defined operation. For applications requiring valid reset signaling all the way to 0V, external passive components (e.g., pullup for open-drain) are needed - though MAX6389XS23D3-T itself does not support sub-1V reset assertion due to its open-drain architecture and internal voltage reference limitations.

Is MAX6389XS23D3-T qualified for automotive applications, and what evidence supports this?

MAX6389XS23D3-T is not explicitly automotive-qualified; its ordering code lacks the "/V" suffix required for AEC-Q100 qualification per the MAX6381–MAX6390 datasheet. While it operates across –40°C to +125°C and meets industrial reliability standards, only variants like MAX6389XS23D3/V+T are certified for automotive use. Engineers selecting MAX6389XS23D3-T for automotive designs must perform additional qualification testing, as the MAX6389XS23D3-T part number itself carries no AEC-Q100 validation.