Analog Devices Inc./Maxim Integrated MAX6338AUB

Overview

The MAX6338AUB from Maxim Integrated is a quad voltage monitor IC designed for multivoltage system supervision, monitoring +5.0V (−10%), +3.3V (−10%), +2.5V (−10%), and an adjustable input (1.23V internal reference) with open-drain active-low outputs. It operates from +2.5V to +5.5V, draws 25µA typical supply current, and guarantees performance across −40°C to +85°C - used in desktop computers, telecom power systems, and industrial controllers.

For engineers reviewing the MAX6338AUB datasheet, MAX6338AUB pinout, MAX6338AUB application, or MAX6338AUB equivalent, key selection criteria include factory-programmed threshold accuracy (±1.5% over temperature), 0.3% built-in hysteresis, undervoltage lockout below 2.5V, wire-ORable open-drain outputs, and µMAX package compatibility with space-constrained PCB layouts.

Technical Context

The MAX6338AUB integrates four independent comparators, each with a precision bandgap reference (1.23V) and factory-trimmed resistive dividers for fixed thresholds. Inputs IN1–IN3 are preset to +5.0V, +3.3V, and +2.5V nominal with −10% trip points; IN4 is auxiliary, accepting user-defined thresholds via external resistor divider referenced to the internal 1.23V node.

All outputs (OUT1–OUT4) are open-drain with 10µA weak internal pull-ups to VCC, enabling direct wire-OR configuration for a single "power good" signal. An internal undervoltage lockout forces all outputs low when VCC drops below 2.5V, ensuring fail-safe behavior during brownout conditions.

Key Specifications

Pinout & Package

The MAX6338AUB is housed in a 10-pin µMAX® package (3.0mm × 3.0mm, 0.6mm height), lead-free compatible, with exposed pad for thermal enhancement (not electrically connected).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6339AUB, the MAX6338AUB omits reset input and watchdog but delivers identical quad monitoring accuracy and lower quiescent current. Against TPS3307-33D, it provides full four-rail coverage with factory-matched −10% tolerances and superior design flexibility for mixed-voltage systems.

Availability

MAX6338AUB is available at Aetrix Electronics and suitable for desktop computers, telecom infrastructure, and industrial PLCs requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX6338AUB 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing markets.

The MAX6338AUB belongs to Maxim's precision voltage supervisor product line, engineered for reliable multirail power sequencing and fault detection in mission-critical embedded systems.

FAQ

What is the exact threshold voltage for the +5.0V input on the MAX6338AUB?

The +5.0V input (IN1) on the MAX6338AUB has a −10% factory-trimmed threshold range of 4.25V to 4.50V (typical 4.38V), specified over −40°C to +85°C. This value is guaranteed by design and does not require external calibration. The MAX6338AUB uses an internal bandgap reference and laser-trimmed resistors to maintain accuracy without external components.

Can the MAX6338AUB monitor a −5.0V rail?

No, the MAX6338AUB cannot monitor a −5.0V rail. Its IN4 input is adjustable but limited to positive voltages referenced to the 1.23V internal threshold; the −5.0V monitoring capability is exclusive to variants like MAX6338MUB/N/PUB. The MAX6338AUB's IN1–IN3 are fixed to +5.0V, +3.3V, and +2.5V, and IN4 supports only user-defined positive thresholds.

How does the undervoltage lockout (UVLO) function in the MAX6338AUB?

The MAX6338AUB's UVLO circuit forces all four outputs (OUT1–OUT4) low whenever VCC drops below 2.5V. This behavior is active down to VCC = 1V and ensures deterministic fault signaling even during severe supply collapse. The MAX6338AUB maintains this state independently of input voltages, making it suitable for brownout protection in systems with unregulated or decaying backup supplies.

Is the MAX6338AUB pin-compatible with other MAX6338 variants?

Yes, all MAX6338 variants including MAX6338AUB share identical 10-pin µMAX package, pinout, and electrical interface. Differences are limited to factory-programmed threshold configurations - IN1–IN4 voltage assignments and tolerance (5% vs. 10%) - with no impact on PCB layout, footprint, or interconnect. The MAX6338AUB can be substituted with other MAX6338_UB parts without hardware modification.

What is the maximum sink current supported by each output of the MAX6338AUB?

Each open-drain output of the MAX6338AUB supports a continuous sink current of 20mA, with VOL ≤ 0.4V at ISINK = 2mA (VCC = 5V) and ≤ 0.4V at ISINK = 1.2mA (VCC = 2.5V). This allows direct driving of LEDs, optocouplers, or logic inputs without external buffers. The MAX6338AUB's outputs remain functional across its full operating temperature and supply range.