Analog Devices Inc./Maxim Integrated MAX6339IUT

Overview

MAX6339IUT from Maxim Integrated is a quad voltage supervisory IC that monitors +5.0V (−10%), +3.3V (−10%), +2.5V (−10%), and +1.8V (−10%) supply rails in multi-rail systems, asserting a single active-low open-drain RESET output when any rail falls below its threshold. It operates from IN2 supply (1.0V to 5.5V), draws only 55µA typical supply current, and guarantees reset timeout ≥140ms. Used in telecom and industrial computing for system integrity during power-up/down.

For engineers reviewing the MAX6339IUT datasheet, MAX6339IUT pinout, MAX6339IUT application, or MAX6339IUT equivalent, key selection criteria include factory-trimmed four-rail monitoring accuracy, −40°C to +85°C operation, SOT23-6 package footprint, 1.0V minimum valid RESET assertion voltage, and immunity to short transients on monitored inputs.

Technical Context

The MAX6339IUT integrates an accurate bandgap reference, four precision comparators with 0.3% hysteresis, and internal resistor-divider networks scaled to fixed thresholds for all four inputs. Each comparator compares its respective input against a trimmed reference derived from the 1.23V internal threshold.

IN2 serves as both the device power supply and the internal pullup source for the open-drain RESET output (10µA typical). RESET remains valid as long as IN1 ≥1V or IN2 ≥1V, enabling robust reset assertion even during partial brownout conditions across monitored rails.

Key Specifications

Pinout & Package

MAX6339IUT is housed in a 6-pin SOT23-6 package (2.9mm × 1.6mm × 1.1mm), optimized for space-constrained PCB layouts in telecom and embedded computing applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad voltage supervisory applications.

Compared with MAX6340IUT and TPS3307-33D, the MAX6339IUT delivers exact match for four-rail low-voltage supervision in SOT23-6 without added complexity or footprint penalty - ideal for space- and cost-sensitive telecom and embedded applications requiring precise −10% tolerance on all rails.

Availability

MAX6339IUT is available at Aetrix Electronics and suitable for telecommunications infrastructure, industrial embedded controllers, and high-end printing systems requiring stable component supply and guaranteed long-term availability.

Supply support for MAX6339IUT 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 management, sensing, and interface applications in demanding industrial and communications environments.

The MAX6339IUT belongs to Maxim's µP supervisory product line, engineered specifically for reliable multi-rail voltage monitoring in space-constrained, thermally varied systems such as telecom line cards and embedded controllers.

FAQ

What voltage rails does the MAX6339IUT monitor and what are their thresholds?

The MAX6339IUT monitors +5.0V (−10% threshold = 4.50V), +3.3V (−10% = 2.97V), +2.5V (−10% = 2.25V), and +1.8V (−10% = 1.62V). These thresholds are factory-trimmed and require no external components. The device asserts RESET if any monitored input falls below its specified threshold, and the reset remains active for ≥140ms after all inputs recover. This configuration is confirmed in the Selector Guide for MAX6339IUT (top mark AAKC).

Can the MAX6339IUT operate if one of its monitored supplies collapses completely?

Yes - the MAX6339IUT remains functional and maintains valid RESET assertion as long as either IN1 or IN2 stays ≥1.0V. Since IN2 powers the device and provides the internal RESET pullup, it must remain active for normal operation. However, even if IN1, IN3, or IN4 drop to 0V, RESET will stay low if IN2 ≥1.0V and any monitored rail is below threshold. This behavior is explicitly guaranteed in the Absolute Maximum Ratings and Electrical Characteristics tables.

Is an external pullup resistor required for the MAX6339IUT RESET output?

No external pullup is required in most cases because the MAX6339IUT includes a 10µA internal pullup to IN2. This suffices for interfacing with 3.3V or 5V logic families when IN2 matches the target logic supply. An external pullup is only needed when driving logic with a different voltage (e.g., 1.8V IO), and even then, the internal circuitry prevents reverse current flow from the external pullup into IN2 - a key design feature documented in the Applications Information section.

How does the MAX6339IUT handle short voltage transients on monitored inputs?

The MAX6339IUT rejects transients ≤100µs duration on any monitored input, as verified in the Typical Operating Characteristics graph "MAXIMUM IN_ TRANSIENT DURATION vs. RESET THRESHOLD OVERDRIVE". This immunity prevents false resets caused by switching noise or load dump events. The built-in 0.3% hysteresis further stabilizes detection near threshold, and both features are inherent to the comparator architecture - no external filtering is needed for basic transient rejection.

What is the supply current consumption of the MAX6339IUT and how is it distributed?

The MAX6339IUT draws 55µA typical supply current from IN2. Per the datasheet Note 4, this splits into ~25µA for internal resistor-divider biasing (for the monitored voltages) and ~30µA for comparator, reference, and timing circuitry. Current scales slightly with IN2 voltage (e.g., 40µA at VIN2 = 2.5V, 115µA at VIN2 = 3.3V), but 55µA is the representative value for +3.0V to +3.3V operation - making it suitable for always-on supervision in power-sensitive systems.