Analog Devices Inc./Maxim Integrated MAX6339EUT+T

Overview

The MAX6339EUT+T from Maxim Integrated is a precision quad voltage supervisory IC that monitors +5.0V, +3.0V, +2.5V, and one user-adjustable input (based on 1.23V internal reference) with ±10% threshold tolerance. It delivers a single active-low open-drain RESET output with 140ms minimum timeout, operates from -40°C to +85°C, and draws only 55µA supply current. It is used in desktop computers and data storage equipment to ensure reliable power-on reset sequencing.

For engineers reviewing the MAX6339EUT+T datasheet, MAX6339EUT+T pinout, MAX6339EUT+T application, or MAX6339EUT+T equivalent, key selection criteria include factory-trimmed multi-rail monitoring capability, IN2-powered operation with RESET validity down to 1V, immunity to short supply transients, and SOT23-6 footprint compatibility for space-constrained embedded systems.

Technical Context

The MAX6339EUT+T integrates an accurate bandgap reference, four precision comparators, and internal trimmed resistor-divider networks to support fixed thresholds for +5.0V (−10%), +3.0V (−10%), and +2.5V (−10%), while the fourth input (IN4) is user-adjustable via external resistor divider referenced to 1.23V. Each comparator includes 0.3% hysteresis to suppress noise-induced false resets.

Power is derived solely from IN2 (+3.0V), which also serves as 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 operation during brownout conditions without external biasing.

Key Specifications

Pinout & Package

The MAX6339EUT+T is housed in a 6-pin SOT23-6 package (JEDEC MO-178AA), with 1.3mm height, 2.9mm × 1.6mm footprint, and gull-wing leads. Pin 1 is marked by a dot; pin numbering follows standard SOT23 top-view orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6340EUT+T and TPS3307-33DBVR, the MAX6339EUT+T uniquely combines quad monitoring, −10% factory thresholds for enhanced margin, and guaranteed 1V RESET validity-making it optimal for cost-sensitive, space-constrained industrial and storage applications requiring robust brownout resilience.

Availability

MAX6339EUT+T is available at Aetrix Electronics and suitable for desktop computers, data storage equipment, and industrial PLC controllers requiring stable component supply, long-term lifecycle support, and RoHS-compliant lead-free packaging.

Supply support for MAX6339EUT+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, mixed-signal, and power management ICs for demanding industrial, communications, and computing applications.

The MAX6339 series was developed specifically for multi-rail microprocessor supervisory functions in compact, high-reliability systems-emphasizing minimal external components, wide temperature operation, and immunity to supply transients.

FAQ

What is the exact function of the IN2 pin on the MAX6339EUT+T?

The IN2 pin on the MAX6339EUT+T serves dual roles: it is both the primary power supply input for the IC and the internal pullup source for the open-drain RESET output. The device draws operating current exclusively from IN2, and the 10µA internal pullup connects RESET to IN2. This architecture eliminates the need for an external pullup resistor in most cases and ensures RESET remains valid as long as IN2 ≥ 1V, enabling operation during partial brownout conditions.

Can the MAX6339EUT+T monitor a +1.8V supply?

No, the MAX6339EUT+T cannot monitor a +1.8V supply. Its fixed threshold configuration (per Selector Guide) specifies IN1 = +5.0V (−10%), IN2 = +3.0V (−10%), IN3 = +2.5V (−10%), and IN4 = adjustable. While other variants like MAX6339CUT support +1.8V, the MAX6339EUT+T's IN3 is factory-trimmed for +2.5V only. To supervise +1.8V, use the adjustable IN4 input with a resistor divider scaled to 1.23V reference.

What is the maximum transient duration the MAX6339EUT+T can ignore on its monitored inputs?

The MAX6339EUT+T can ignore transients up to 100µs in duration on any monitored input, provided the overdrive (difference between actual voltage and threshold) exceeds 50mV. This immunity is confirmed in the Typical Operating Characteristics graph "Maximum IN_ Transient Duration vs. Reset Threshold Overdrive" (MAX6339toc04), where the device remains untripped above the defined boundary line. This feature prevents false resets caused by switching noise or coupling spikes in dense PCB layouts.

Does the MAX6339EUT+T require external capacitors for stable operation?

The MAX6339EUT+T does not require external capacitors for basic functionality, as all thresholds are factory-trimmed and internally compensated. However, a 0.1µF ceramic bypass capacitor from IN2 to GND is recommended in noisy environments to improve immunity to supply ripple. Additional 0.1µF capacitors may be added to IN1, IN3, and IN4 if higher noise rejection is needed-though this increases response time and must be evaluated against system timing requirements.

How is the adjustable threshold on the MAX6339EUT+T configured?

The adjustable threshold on the MAX6339EUT+T is configured using an external resistor divider connected to IN4, referenced to the internal 1.23V ±0.03V bandgap voltage. The formula is V_INTH = 1.23V × (R1 + R2)/R2, where R2 connects IN4 to GND and R1 connects IN4 to the target supply. With ±0.1µA input current, R2 values up to 100kΩ maintain <1% error. For example, to monitor 3.3V: R1 = R2 × ((3.3 / 1.23) − 1) ≈ 1.69 × R2.