Analog Devices Inc./Maxim Integrated MAX6339NUT

Overview

MAX6339NUT from Maxim Integrated is a quad voltage supervisory IC that monitors +5.0V, +3.0V, user-adjustable, and -5.0V supply rails with ±5% threshold tolerance, delivers active-low open-drain RESET output, features 140ms minimum reset timeout, operates from -40°C to +85°C, and is used in telecom and industrial power integrity systems.

For engineers reviewing the MAX6339NUT datasheet, MAX6339NUT pinout, MAX6339NUT application, or MAX6339NUT equivalent, key selection criteria include verified quad-supply monitoring capability, factory-trimmed -5V and +5V thresholds, guaranteed 1V minimum valid operation on IN1/IN2, low 55µA supply current, and SOT23-6 package compatibility with space-constrained embedded designs.

Technical Context

The MAX6339NUT integrates four precision comparators with an internal 1.23V bandgap reference and factory-trimmed resistor-divider networks for fixed thresholds (+5.0V, +3.0V, -5.0V), while one input supports user-adjustable monitoring via external resistor divider. It uses built-in 0.3% hysteresis per comparator to suppress noise-induced false resets.

RESET assertion is triggered when any monitored voltage falls below its threshold (or rises above for -5V), remains asserted for ≥140ms after all inputs recover, and stays valid as long as IN1 ≥1V or IN2 ≥1V - enabling reliable reset hold during brownout recovery without external timing components.

Key Specifications

Pinout & Package

The MAX6339NUT is housed in a 6-pin SOT23-6 package with exposed pad not electrically connected; footprint compatible with JEDEC MO-178AA, 1.6mm × 2.9mm body size, 0.95mm height, and 0.95mm pin pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6340NUT and TPS3808G33, the MAX6339NUT uniquely combines quad monitoring, factory-trimmed -5V detection, and one user-adjustable input in SOT23-6 - making it the sole option for compact systems requiring mixed positive/negative and custom rail supervision without layout changes.

Availability

MAX6339NUT is available at Aetrix Electronics and suitable for telecommunications infrastructure, industrial PLCs, high-end printers, and data storage equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6339NUT 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, mixed-signal, and power management ICs for industrial, communications, and computing applications.

The MAX6339NUT belongs to Maxim's µP supervisory product line, engineered specifically for multi-rail system integrity in space-constrained, thermally demanding environments where simultaneous voltage monitoring and deterministic reset timing are critical.

FAQ

What is the exact reset threshold voltage for the -5V input on the MAX6339NUT?

The MAX6339NUT has a factory-trimmed -5V input threshold of -4.50V to -4.25V (+10% tolerance), meaning RESET asserts when the IN4 voltage rises above -4.50V. This specification is guaranteed over -40°C to +85°C and is documented in the Electrical Characteristics table under "-5V (+10%) threshold".

Can the MAX6339NUT monitor a +1.2V supply, and how is it configured?

Yes, the MAX6339NUT can monitor +1.2V using its user-adjustable IN3 input. Since the internal reference is 1.23V, a resistor-divider must scale +1.2V down to 1.23V at the input. For example, using R1 = 0Ω and R2 = ∞ (direct connection) is invalid; instead, configure R1/R2 so V_IN3 = 1.23V × (R1 + R2)/R2 = 1.2V - yielding R1 ≈ -0.024×R2, which confirms +1.2V is below the 1.20V minimum reference and thus not reliably detectable. Therefore, +1.2V monitoring is not supported; minimum practical adjustable voltage is ~1.20V.

Does the MAX6339NUT require external components to supervise +5.0V, +3.0V, and -5.0V rails?

No, the MAX6339NUT requires zero external components to supervise +5.0V (IN1), +3.0V (IN2, also powers the device), and -5.0V (IN4) rails. These three inputs use factory-trimmed internal resistor-divider networks matched to their respective thresholds. Only the fourth input (IN3, user-adjustable) requires an external resistor-divider if a nonstandard voltage is monitored.

What is the minimum valid supply voltage for RESET functionality in the MAX6339NUT?

The MAX6339NUT guarantees RESET output validity as long as either IN1 ≥ 1.0V or IN2 ≥ 1.0V - even if other inputs fall below their thresholds or drop to 0V. This allows the device to assert and hold RESET during deep brownout conditions on all but one supply, ensuring fail-safe behavior in multi-rail systems.

How does the MAX6339NUT handle short-duration voltage transients on monitored inputs?

The MAX6339NUT rejects transients ≤100µs duration when the monitored voltage deviates by ≥50mV from its threshold, as confirmed by the "Maximum IN_ Transient Duration vs. Reset Threshold Overdrive" graph in the datasheet. This immunity prevents false resets caused by switching noise or coupling spikes without compromising response to sustained undervoltage faults.