Analog Devices Inc./Maxim Integrated MAX4917AELT+T

Overview

MAX4917AELT+T from Maxim Integrated is a 300mA autoretry current-limit switch designed for SDIO, USB, and portable device power rail protection. It features 0.2Ω on-resistance, 2.3V–5.5V supply range, 14ms guaranteed blanking time, and open-drain FLAG output for fault reporting. Used in notebook computers and handheld devices to prevent host damage during load faults.

For engineers reviewing the MAX4917AELT+T datasheet, MAX4917AELT+T pinout, MAX4917AELT+T application, or MAX4917AELT+T equivalent, key selection criteria include forward current limit (300mA min), autoretry behavior vs. latchoff, reverse current protection (450mA), shutdown current (0.01μA typ), and μDFN-6 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX4917AELT+T integrates forward/reverse current sensing using internal sense resistors compared against dual reference voltages, enabling independent detection of overcurrent in both directions. Its autoretry function initiates a 210ms–900ms retry cycle after 14ms blanking, automatically restoring power only when the overload condition clears.

It includes undervoltage lockout (1.75V–2.25V rising threshold), thermal shutdown at +150°C with 15°C hysteresis, and reverse current limiting that activates when VOUT − VIN ≥ 0.5V. The open-drain FLAG output requires an external pullup to IN and remains asserted low until fault removal in autoretry mode.

Key Specifications

Pinout & Package

MAX4917AELT+T is housed in a lead-free, RoHS-compliant 6-pin μDFN package (2mm × 2mm, outline L622-1), optimized for high-density portable PCBs. Thermal performance supports continuous operation up to +85°C ambient with 358mW max dissipation at +70°C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current-limit switch applications.

Compared with MAX4917BELT+T, MAX4917AELT+T provides autonomous recovery without host involvement; compared with MAX4915AELT+T, it delivers 50% higher current capacity for demanding USB 3.0 or high-speed SDIO loads - critical for future-proofing compact portable designs.

Availability

MAX4917AELT+T is available at Aetrix Electronics and suitable for SDIO card interfaces, USB port protection, and battery-backed real-time clock power management requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for MAX4917AELT+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for portable, industrial, and communications systems.

The MAX4914B/MAX4915A/B/MAX4917A/B family was designed specifically for intelligent load switching in space-constrained, battery-sensitive applications - delivering integrated current limiting, reverse protection, and fault signaling in sub-2mm² packages.

FAQ

What is the guaranteed forward current limit for MAX4917AELT+T?

The MAX4917AELT+T guarantees a minimum forward current limit of 300mA at +25°C, with a maximum of 450mA across the full -40°C to +85°C operating range. This rating applies when OUT is shorted to GND and ensures robust protection for high-capacitance SDIO and USB loads without damaging the host controller. The actual trip point is process- and temperature-stable per Maxim's design correlation.

Does MAX4917AELT+T support reverse current limiting, and what is its threshold?

Yes, MAX4917AELT+T provides reverse current limiting with a guaranteed minimum threshold of 450mA when VOUT exceeds VIN by ≥0.5V. This protects upstream power sources from backfeed during hot-swap or fault conditions. The reverse limit is independently monitored and triggers FLAG assertion after the 14ms blanking period if sustained - identical in timing behavior to forward overcurrent response.

How does the autoretry function operate in MAX4917AELT+T?

In MAX4917AELT+T, autoretry initiates after the 14ms blanking period expires during an overcurrent event: the switch turns OFF, waits 210–900ms (tRETRY), then attempts to re-enable. If the overload persists, it repeats the cycle; if cleared, it remains ON and deasserts FLAG. This behavior is intrinsic to the "A" suffix variant and requires no external timing components or firmware control.

What is the recommended external pullup for the FLAG pin of MAX4917AELT+T?

The FLAG pin of MAX4917AELT+T is an open-drain output requiring an external pullup resistor to IN. A 10kΩ resistor is typically used for fast rise time and low power; values from 4.7kΩ to 100kΩ are acceptable depending on system noise immunity and response speed requirements. Pulling to IN (not VCC) ensures correct logic level referencing and minimizes leakage during shutdown.

Can MAX4917AELT+T be used in place of MAX4917BELT+T without hardware changes?

No - although MAX4917AELT+T and MAX4917BELT+T share identical pinout, package, and electrical specs except fault recovery behavior, substituting the autoretry (A) version for the latchoff (B) version changes system-level fault handling. MAX4917AELT+T will autonomously recover from transient faults, whereas MAX4917BELT+T remains latched until ON or VIN is cycled. Firmware and failure-mode analysis must be revalidated.