Analog Devices Inc./Maxim Integrated MAX6399ATA+T

Overview

The MAX6399ATA+T from Analog Devices is a high-voltage overvoltage/undervoltage protection switch controller that monitors DC-DC converter input and output voltages, drives an external n-channel MOSFET via a charge-pump GATE output (V_GS = 10V), features adjustable thresholds (SET = 0.5V typ, OUT_SET = 1.23V typ), and operates from 5.75V to 72V across –40°C to +125°C - used in telecom server power rails for load isolation during transients.

For engineers reviewing the MAX6399ATA+T datasheet, MAX6399ATA+T pinout, MAX6399ATA+T application, or MAX6399ATA+T equivalent, this page delivers verified functional role, validated pin functions, confirmed thermal shutdown behavior, exact TDFN-8 package dimensions, and two field-validated alternative controllers with documented threshold and latch differences.

Technical Context

The MAX6399ATA+T implements a dual-threshold protection architecture: SET pin senses DC-DC output voltage for overvoltage (0.5V rising threshold), while OUT_SET senses DC-DC input for undervoltage (1.23V rising threshold); both thresholds exhibit 5% hysteresis. Its internal charge pump ensures V_GATE = V_IN + 10V (min) to fully enhance external n-channel MOSFETs.

Upon overvoltage detection, GATE latches low with 20mA sink capability and remains off until IN power cycle or SHDN toggle; POK provides open-drain power-good signaling with 35µs delay and 0.45V VOL at 3.2mA sink; thermal shutdown activates at +150°C with 20°C hysteresis and requires direct thermal coupling to the external MOSFET.

Key Specifications

Pinout & Package

MAX6399ATA+T is housed in an 8-pin TDFN package (3.0mm × 3.0mm × 0.75mm, exposed pad), RoHS-compliant, with thermal pad connected to GND for enhanced heat dissipation and thermal shutdown accuracy.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar overvoltage/undervoltage protection switch controller applications.

Compared with TPS26631RGER and LT4363IMS-2#PBF, the MAX6399ATA+T uniquely supports independently adjustable OVP and UVLO thresholds with a dedicated POK output and integrated charge pump - enabling flexible, high-accuracy protection in multi-rail telecom and server platforms where external MOSFET sizing and sequencing control are critical.

Availability

MAX6399ATA+T is available at Aetrix Electronics and suitable for telecom power shelves, industrial server PSUs, automotive ADAS ECUs, and RAID controller power domains requiring stable component supply, long-term lifecycle support, and guaranteed RoHS compliance.

Supply support for MAX6399ATA+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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA.

The MAX6399ATA+T belongs to Analog Devices' high-voltage protection controller product line, designed specifically for robust, programmable overvoltage/undervoltage isolation in DC-DC converter front-ends across automotive, telecom, and industrial infrastructure.

FAQ

What is the function of the SET pin on the MAX6399ATA+T?

The SET pin on the MAX6399ATA+T serves as the overvoltage sense input with a precise 0.5V (typ) rising threshold. It connects to a resistor divider on the DC-DC converter output to program the overvoltage protection point. When the divided voltage exceeds 0.5V, the MAX6399ATA+T immediately latches GATE low to disconnect the load. The 5% hysteresis prevents oscillation near the threshold, and input bias current is limited to ±50nA to minimize divider error - ensuring accurate, stable OVP across temperature.

How does the MAX6399ATA+T provide gate drive for external n-channel MOSFETs?

The MAX6399ATA+T integrates a high-efficiency charge pump that generates a GATE voltage of V_IN + 10V (min) during normal operation, guaranteeing full enhancement of low-R_DS(ON) n-channel MOSFETs. This eliminates the need for an external boost supply. The GATE output sources 100µA and sinks 20mA, enabling fast turn-on and sub-microsecond turn-off even with 6nF gate capacitance. During overvoltage, GATE latches low and remains off until SHDN is toggled or IN is recycled - a key safety feature confirmed in the MAX6399ATA+T datasheet.

Can the MAX6399ATA+T monitor both input and output voltages simultaneously?

Yes, the MAX6399ATA+T monitors both input and output voltages simultaneously using two independent sensing paths: the SET pin detects overvoltage on the DC-DC output, while the OUT_SET pin detects undervoltage on the DC-DC input. Each has its own precision threshold (0.5V for SET, 1.23V for OUT_SET) and 5% hysteresis. The POK output reflects only the OUT_SET condition, asserting low when the input falls below its threshold - allowing coordinated power sequencing. This dual-monitoring capability is explicitly defined in the MAX6399ATA+T functional diagram and electrical characteristics table.

What is the purpose of the exposed pad on the MAX6399ATA+T TDFN package?

The exposed pad on the MAX6399ATA+T TDFN package must be soldered to the PCB ground plane to serve two critical functions: (1) it provides low-thermal-resistance conduction path for heat dissipation, essential for reliable operation at +125°C ambient; and (2) it establishes the thermal reference for the internal overtemperature detector, which requires direct thermal coupling to the external MOSFET to activate shutdown at +150°C. The datasheet specifies "CONNECT TO GND" and warns that improper pad connection degrades thermal shutdown accuracy - a requirement strictly enforced in MAX6399ATA+T layout guidelines.

Does the MAX6399ATA+T include built-in protection against thermal overload?

Yes, the MAX6399ATA+T includes an internal overtemperature detector that disables the GATE output when the junction temperature reaches +150°C, protecting both the IC and the external MOSFET. The thermal shutdown has 20°C hysteresis, releasing GATE when temperature drops to +130°C. Crucially, the datasheet states this feature requires "close thermal contact with the external MOSFET" - meaning the MAX6399ATA+T must be placed adjacent to the MOSFET on the same thermal island. This behavior is measured and specified in the Electrical Characteristics table under "Thermal-Shutdown Temperature" and confirmed in the Detailed Description section.