Analog Devices Inc./Maxim Integrated MAX6389XS33D1+T

Overview

MAX6389XS33D1+T from Maxim Integrated is a low-power microprocessor supervisory circuit with open-drain active-low reset output, factory-set 3.30V ±2.5% reset threshold, and 140ms minimum VCC reset timeout. It monitors VCC from +1.0V to +5.5V, features auxiliary RESET IN input for dual-voltage monitoring, and operates across -40°C to +125°C - used in automotive-grade dual-rail power systems requiring reliable brownout detection.

For engineers reviewing the MAX6389XS33D1+T datasheet, MAX6389XS33D1+T pinout, MAX6389XS33D1+T application, or MAX6389XS33D1+T equivalent, key selection criteria include its 3.30V threshold accuracy over temperature, 140ms reset timeout, open-drain output requiring external pullup, auxiliary voltage monitor capability, and AEC-Q100-qualified 4-pin SC70 package.

Technical Context

The MAX6389XS33D1+T implements a precision bandgap-based reset comparator with ±2.5% threshold tolerance over -40°C to +125°C and 60ppm/°C tempco. Its auxiliary RESET IN input compares against an internal 1.27V reference, enabling user-defined secondary voltage monitoring via external resistor divider.

Reset assertion occurs when either VCC falls below 3.30V or RESET IN drops below its derived threshold; deassertion follows a guaranteed 140ms minimum timeout after recovery. The open-drain RESET output supports rail-to-rail compatibility and level-shifting, with VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.5V) and leakage < 1.0µA when inactive.

Key Specifications

Pinout & Package

MAX6389XS33D1+T is housed in a RoHS-compliant 4-pin SC70 package (outline 21-0098, land pattern 90-0187), optimized for thermal performance (θJA = 322.6°C/W) and high-density layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6389XS33D1+T, the MAX6389XS33D2+T extends reset hold time without altering threshold or interface, while TLV803EB33DBZR trades dual-monitoring capability and AEC-Q100 qualification for lower cost and smaller size in simpler systems.

Availability

MAX6389XS33D1+T is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLCs, battery-powered telematics gateways, and rail-specific power sequencing applications requiring stable component supply and long-term lifecycle support.

Supply support for MAX6389XS33D1+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 automotive, industrial, and communications markets, emphasizing reliability, low power, and integration.

The MAX6381–MAX6390 family delivers single/dual low-voltage microprocessor supervisory circuits targeting space-constrained, high-reliability applications where accurate voltage monitoring and robust reset timing are critical.

FAQ

What is the exact reset threshold voltage of MAX6389XS33D1+T and how stable is it over temperature?

The MAX6389XS33D1+T has a factory-set reset threshold of 3.30V with ±2.5% accuracy over the full -40°C to +125°C operating range. Its temperature coefficient is 60ppm/°C, ensuring minimal drift across automotive and industrial thermal profiles. This stability is confirmed in the Electrical Characteristics table on page 3 of the official datasheet, where VTH min/max values are specified at extreme temperatures.

Does MAX6389XS33D1+T support monitoring of a second voltage rail, and how is it implemented?

Yes, MAX6389XS33D1+T supports dual-voltage monitoring via its dedicated RESET IN pin (Pin 4), which compares an external voltage against an internal 1.27V reference. To set a custom threshold, connect a resistor divider between the secondary rail and ground, with the midpoint fed to RESET IN. The MAX6389XS33D1+T asserts reset if either VCC falls below 3.30V or the voltage at RESET IN drops below its derived threshold.

What is the function and electrical behavior of the RESET output on MAX6389XS33D1+T?

The RESET output of MAX6389XS33D1+T is an open-drain, active-low signal requiring an external pullup resistor. When asserted, it sinks up to 1.2mA at VCC ≥ 2.5V with VOL ≤ 0.3V; when inactive, leakage is < 1.0µA. This architecture enables level-shifting, wired-OR reset buses, and compatibility with diverse logic families - a key differentiator from push-pull alternatives.

Is MAX6389XS33D1+T qualified for automotive applications, and what does the "/V" suffix indicate?

MAX6389XS33D1+T carries the "+" suffix indicating RoHS compliance but not the "/V" suffix; however, it is AEC-Q100 qualified per the datasheet's Features section and Ordering Information notes. The "/V" variant (e.g., MAX6389XS33D1/V+T) denotes a specific automotive-qualified version with enhanced screening - MAX6389XS33D1+T itself meets AEC-Q100 stress test requirements for Grade 1 (-40°C to +125°C).

What package type and pin configuration does MAX6389XS33D1+T use, and where can I find the land pattern?

MAX6389XS33D1+T uses a 4-pin SC70 package (outline number 21-0098, package code X4+1). Pin 1 = VCC, Pin 2 = RESET, Pin 3 = GND, Pin 4 = RESET IN. The recommended land pattern is 90-0187, available at maximintegrated.com/packages. Thermal resistance is θJA = 322.6°C/W on a multilayer board, per JEDEC JESD51-7.