Analog Devices Inc./Maxim Integrated MAX6399ATA

Overview

MAX6399ATA from Maxim Integrated 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 charge-pump GATE output (V_GS = 10V), latches off during overvoltage faults, and provides open-drain POK signaling. It operates from 5.75V to 72V, features adjustable thresholds (SET = 0.5V typ, OUT_SET = 1.23V typ), and is rated for -40°C to +125°C.

For engineers reviewing the MAX6399ATA datasheet, MAX6399ATA pinout, MAX6399ATA application, or MAX6399ATA equivalent, this device supports precise DC-DC rail protection in telecom power systems, server VRM supervision, RAID storage power sequencing, and hot-swap input transient mitigation - with attention to GATE latch behavior, thermal shutdown coordination, and resistor-divider threshold programming.

Technical Context

The MAX6399ATA implements dual-threshold monitoring: SET pin detects DC-DC output overvoltage using a 0.5V rising comparator with 5% hysteresis, while OUT_SET senses DC-DC input undervoltage via a 1.23V rising threshold. Its internal charge pump generates GATE voltage 10V above IN (for VIN ≥14V), ensuring full enhancement of external n-channel MOSFETs with R_DS(ON) down to milliohm levels.

GATE output latches low on overvoltage fault and remains latched until SHDN toggle or IN power cycle; POK asserts low when OUT_SET falls below threshold; thermal shutdown activates at +150°C with 20°C hysteresis. All functions operate across full -40°C to +125°C ambient range with guaranteed performance at extremes.

Key Specifications

Pinout & Package

MAX6399ATA is housed in an 8-pin TDFN package (3mm × 3mm × 0.8mm) with exposed pad (EP) for thermal dissipation; EP must be connected to GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS26631RGER and LT4363IMS-2#PBF, the MAX6399ATA uniquely combines 72V operation, resistor-programmable thresholds, integrated charge pump, and latch-only fault response - making it optimal for high-reliability telecom and server power domains requiring deterministic isolation behavior and thermal co-location with the protected MOSFET.

Availability

MAX6399ATA is available at Aetrix Electronics and suitable for telecom infrastructure, server power management, and industrial RAID storage applications requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +125°C operation.

Supply support for MAX6399ATA 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 MAX6399ATA belongs to Maxim's high-voltage protection controller product line, engineered specifically for reliable DC-DC converter supervision in telecom and server power systems where overvoltage latch behavior and thermal coordination with external MOSFETs are critical design requirements.

FAQ

What is the maximum input voltage the MAX6399ATA can withstand?

The MAX6399ATA has an absolute maximum IN voltage rating of +80V. Its operational supply range is specified from 5.75V to 72V, meaning it functions reliably up to 72V under normal conditions. Exceeding 72V risks violating the guaranteed electrical characteristics, though the 80V absolute max provides limited transient margin. For sustained 72V+ operation, external clamping (e.g., TVS diode) is recommended. The MAX6399ATA must never be biased beyond 80V on any pin.

How does the MAX6399ATA's GATE latch behavior differ from standard eFuses?

Unlike most eFuses that auto-retry after fault clearance, the MAX6399ATA's GATE output remains latched off indefinitely after an overvoltage event - it will not recover until either the IN supply is cycled or the SHDN pin is actively toggled. This eliminates uncontrolled reconnection during unstable conditions. The MAX6399ATA thus provides deterministic, operator- or system-controlled reset behavior essential for safety-critical telecom and server power domains.

Can the MAX6399ATA drive a MOSFET without an external gate resistor?

Yes - the MAX6399ATA's internal charge pump and 20mA GATE sink capability allow direct connection to small-to-medium gate capacitance n-MOSFETs (e.g., ≤10nF) without external gate resistors. However, for larger MOSFETs or when controlling inrush slew rate, a series gate resistor is recommended per Figure 5 in the datasheet. The MAX6399ATA's GATE driver is optimized for fast switching but does not include built-in slew control; external components manage EMI and dV/dt.

What is the purpose of the exposed pad (EP) on the MAX6399ATA package?

The exposed pad (EP) on the MAX6399ATA's TDFN-8 package serves as the primary thermal path to the PCB ground plane. It must be soldered directly to a solid copper GND pour to ensure effective heat dissipation - especially critical for thermal shutdown coordination with the external MOSFET. Electrical connection to GND is mandatory; floating or unconnected EP degrades thermal performance and may cause premature thermal shutdown or parameter drift. The MAX6399ATA's reliability and full -40°C to +125°C specification depend on proper EP mounting.

How do I calculate the resistor divider for the OUT_SET pin to set a 9V undervoltage threshold?

To set a 9V undervoltage threshold on OUT_SET, use R₂ = (V_TH × R_TOTAL) / V_UV, where V_TH = 1.23V (OUT_SET threshold), V_UV = 9V, and R_TOTAL ≤ 1.8MΩ (to maintain ≥100× I_SET bias current). Selecting R_TOTAL = 1.79MΩ yields R₂ = 246kΩ and R₁ = 1.544MΩ. Standard values: R₁ = 1.54MΩ, R₂ = 246kΩ. This configuration ensures accurate UVLO activation at 9V while keeping input bias error <0.5%. The MAX6399ATA's OUT_SET input draws only ±50nA, enabling high-impedance dividers.