Analog Devices Inc./Maxim Integrated MAX6398ATT+T

Overview

MAX6398ATT+T from Maxim Integrated is a high-voltage overvoltage protection controller that monitors input voltage and drives an external n-channel MOSFET to disconnect the load during transients up to 72V. It features adjustable overvoltage threshold (set via SET pin), internal charge-pump gate drive (up to +10V above IN), thermal shutdown, and operates from -40°C to +125°C in industrial power-rail protection applications.

For engineers reviewing the MAX6398ATT+T datasheet, MAX6398ATT+T pinout, MAX6398ATT+T application, or MAX6398ATT+T equivalent, this device serves as a precision overvoltage switch/limiter for 5.5V–72V supply rails requiring fast fault response (<100ns GATE pull-down), low quiescent current (11–20µA in shutdown), and robust thermal management in space-constrained industrial systems.

Technical Context

The MAX6398ATT+T implements a comparator-based overvoltage detection circuit with 1.215V SET threshold and 5% hysteresis, controlling an integrated charge-pump gate driver that delivers 75µA sourcing current and clamps GATE-to-OUT at ≤18V. It supports two operational modes: overvoltage switch (GATE pulled low to disconnect load) and overvoltage limiter (GATE sawtoothing to regulate output voltage).

Unlike the MAX6397, the MAX6398ATT+T omits the linear regulator and POK output - it contains only the protection control core: IN, SHDN, SET, GND, GATE, and OUT pins. Its UVLO activates at 4.66V (rising), with 175mV hysteresis, and it disables GATE during thermal shutdown at +150°C (20°C hysteresis).

Key Specifications

Pinout & Package

MAX6398ATT+T is housed in a thermally enhanced 6-pin TDFN-EP (3mm × 3mm) package with exposed pad (EP) tied to GND for optimal heat dissipation and EMI reduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPD3S014RTER and LT4363IMS-1#PBF, the MAX6398ATT+T uniquely balances ultra-low shutdown current (11µA), precise user-adjustable overvoltage threshold (via SET), and integrated charge-pump gate drive - making it optimal for high-voltage industrial rails where efficiency, configurability, and compactness are jointly critical.

Availability

MAX6398ATT+T is available at Aetrix Electronics and suitable for industrial power rails, FireWire® interface protection, notebook adapter input stages, and wall-cube power devices requiring stable component supply across extended temperature and high-voltage operating conditions.

Supply support for MAX6398ATT+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 high-reliability power management ICs for demanding industrial, automotive, and communications applications.

The MAX6397/MAX6398 product line was engineered specifically for high-voltage overvoltage protection in space-constrained industrial power systems - delivering configurable switch/limiter functionality with minimal external components and guaranteed operation up to +125°C.

FAQ

What is the key functional difference between MAX6398ATT+T and MAX6397?

The MAX6398ATT+T is a dedicated overvoltage protection controller without an integrated linear regulator or POK output, whereas the MAX6397 includes a 100mA always-on linear regulator (5V/3.3V/2.5V/1.8V) and open-drain power-good signal. The MAX6398ATT+T uses only 6 pins versus 8, excludes REG and POK pins, and consumes less quiescent current in shutdown (11–20µA vs. 37–45µA). Both share identical protection architecture, SET threshold, GATE drive, and thermal shutdown behavior.

How do I configure MAX6398ATT+T for overvoltage limiting instead of switching?

To configure MAX6398ATT+T as a voltage limiter, connect the SET pin to a resistor divider from OUT (not IN) - this makes the device monitor output voltage rather than input voltage. During overvoltage, GATE will sawtooth to regulate OUT at the programmed threshold. Ensure the external n-MOSFET's R_DS(ON) and thermal design accommodate continuous power dissipation during sustained overvoltage events. The MAX6398ATT+T automatically enters limiter mode based solely on feedback topology - no register writes or configuration pins are involved.

What is the maximum allowable voltage at the IN pin of MAX6398ATT+T?

The absolute maximum rating for the IN pin of MAX6398ATT+T is +80V, as specified in the Absolute Maximum Ratings table. However, normal operation is guaranteed only up to +72V. Transient excursions beyond +72V but within +80V are survivable if duration is short (e.g., <100ns) and energy is limited by proper PCB layout and external clamping (e.g., TVS diode). Sustained operation above +72V risks violating electrical specifications and may trigger thermal shutdown due to increased power dissipation in the charge pump and internal circuitry.

Does MAX6398ATT+T require an external capacitor on the GATE pin?

No, MAX6398ATT+T does not require an external capacitor on the GATE pin for basic operation. However, adding a small capacitor (e.g., 100pF–1nF) from GATE to GND can reduce sensitivity to fast-rising input transients by acting as a low-pass filter against drain-to-gate capacitance coupling. This is recommended only for systems with very large external MOSFETs (C_iss > 5nF) or extremely fast transients (>10V/ns). The datasheet notes that a 0.1µF capacitor at GATE mitigates ringing for C_gd = 6000pF, but such values are application-specific and not mandatory for standard use.

Can MAX6398ATT+T drive a p-channel MOSFET instead of an n-channel MOSFET?

No, MAX6398ATT+T is designed exclusively to drive n-channel MOSFETs configured as high-side switches. Its GATE output is a charge-pump–based high-side driver that sources current to pull the gate above the source (OUT), enabling full enhancement of n-MOSFETs. It cannot sink sufficient current or provide negative gate drive needed for p-channel MOSFETs. For p-channel solutions, a dedicated high-side driver or alternative controller (e.g., LTC4365) is required - MAX6398ATT+T's architecture, pinout, and internal circuitry assume n-channel topology.