Analog Devices Inc./Maxim Integrated MAX6389XS46D3

Overview

The MAX6389XS46D3 from Maxim Integrated is a low-power, open-drain active-low microprocessor supervisory circuit with factory-set 4.63V 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 MAX6389XS46D3 datasheet, MAX6389XS46D3 pinout, MAX6389XS46D3 application, or MAX6389XS46D3 equivalent, key selection considerations include its 4.63V ±2.5% threshold accuracy over –40°C to +125°C, open-drain output requiring external pull-up, auxiliary voltage monitor capability via RESET IN, and SC70-4 package compatibility with space-constrained embedded designs.

Technical Context

The MAX6389XS46D3 integrates a precision bandgap reference and comparator to monitor VCC against a fixed 4.63V threshold while simultaneously supporting user-adjustable secondary voltage monitoring via the RESET IN pin, which compares against an internal +1.27V reference. Its reset assertion logic is triggered by either VCC falling below 4.63V or RESET IN falling below its derived threshold, with independent timing control.

It features a dedicated open-drain RESET output with guaranteed VOL ≤ 0.3V at ISINK = 80µA and leakage < 1.0µA when deasserted, enabling flexible interface with diverse µP reset inputs. The device uses BiCMOS process technology (647 transistors) and achieves ±2.5% threshold accuracy across full industrial temperature range without external calibration.

Key Specifications

Pinout & Package

MAX6389XS46D3 is housed in a lead-free 4-pin SC70 package (package code X4-1), measuring 1.5mm × 1.0mm × 0.8mm, suitable 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 MAX6389XS46D3, the LT46D3 variant offers identical supervision functionality in a thermally superior µDFN package, while the TPS3808G33DBVR trades dual-rail capability and threshold flexibility for ultra-low current and simpler interface-making it suitable only for single-voltage 3.3V systems.

Availability

MAX6389XS46D3 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 across extended temperature ranges and long production lifecycles.

Supply support for MAX6389XS46D3 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 markets.

The MAX6381–MAX6390 family was designed specifically for low-power, precision microprocessor reset supervision in space- and energy-constrained embedded systems, emphasizing factory-trimmed accuracy, wide temperature operation, and dual-supply monitoring capability.

FAQ

What is the exact reset threshold voltage of the MAX6389XS46D3?

The MAX6389XS46D3 has a factory-set nominal reset threshold of +4.63V, with guaranteed tolerance of ±2.5% over the full operating temperature range of –40°C to +125°C. This value is confirmed in the Reset Thresholds table of the datasheet, where suffix "46" corresponds to VTH(nom) = 4.63V, VTH(min) = 4.51V, and VTH(max) = 4.74V.

Does the MAX6389XS46D3 support monitoring of a second voltage rail?

Yes, the MAX6389XS46D3 supports dual-voltage supervision via its dedicated RESET IN pin. This pin connects to an internal +1.27V reference comparator, allowing users to set a custom reset threshold for a secondary supply using an external resistor divider. This feature is explicitly documented in the Pin Description and Detailed Description sections for MAX6387/MAX6388/MAX6389 variants.

What package type and dimensions does the MAX6389XS46D3 use?

The MAX6389XS46D3 is packaged in a lead-free 4-pin SC70 (package code X4-1), with outline dimensions of 1.5mm × 1.0mm × 0.8mm. This information is specified in the Ordering Information table and Package Information section, confirming compatibility with standard SC70-4 assembly processes and footprint libraries.

What is the minimum reset timeout period for the MAX6389XS46D3?

The MAX6389XS46D3 has a minimum reset timeout period of 140ms, as indicated by the "D3" suffix in its part number. This value is listed in the Reset Timeout Delay table, where D3 corresponds to tRP(min) = 140ms for MAX6381–MAX6389 devices. The timeout begins when VCC rises above the 4.63V threshold and ensures µP reset remains asserted long enough for full initialization.

Is an external pull-up resistor required for the MAX6389XS46D3's RESET output?

Yes, an external pull-up resistor is mandatory for the MAX6389XS46D3 because its RESET output is open-drain active-low. As stated in the Pin Description and General Description, the open-drain configuration requires an external pull-up to the target µP's reset voltage rail (e.g., 3.3V or 5V) to establish a defined high state when reset is deasserted. Typical values range from 10kΩ to 100kΩ depending on bus capacitance and rise-time requirements.