Diodes Incorporated AP2181AFM-7

Overview

AP2181AFM-7 from Diodes Incorporated is a single-channel, active-low high-side USB power switch optimized for hot-swap and USB 2.0-compliant applications. It delivers 2.1A accurate current limiting, 95mΩ typical R_DS(ON) at +25°C, 0.6ms typical rise time, and integrated short-circuit/thermal protection with 7ms deglitch on the open-drain FLG output - enabling robust port power control in laptop docking stations and self-powered USB hubs.

For engineers reviewing the AP2181AFM-7 datasheet, AP2181AFM-7 pinout, AP2181AFM-7 application, or AP2181AFM-7 equivalent, this device is selected for precise current-limited hot-plug insertion, reverse-current blocking, UVLO-enabled safe power sequencing, and fault reporting without external components in space-constrained U-DFN2018-6 layouts.

Technical Context

The AP2181AFM-7 integrates a low-R_DS(ON) N-channel MOSFET with internal current-sense FET architecture, eliminating external sense resistors while maintaining ±10% current-limit accuracy across -40°C to +85°C. Its UVLO threshold (1.9V typ.) ensures turn-on only after stable input rail establishment, and thermal shutdown triggers at +140°C with +25°C hysteresis for autonomous fault recovery.

Control logic implements active-low EN with 0.8V max V_IL and 2.0V min V_IH, driving the output through a soft-start-controlled gate driver. The FLG pin asserts low after 7ms blanking upon over-current or over-temperature events, supporting host-controller fault logging without false triggering from capacitive inrush.

Key Specifications

Pinout & Package

AP2181AFM-7 uses the U-DFN2018-6 package (2.0mm × 1.8mm, 0.5mm pitch), featuring an exposed thermal pad that must be soldered to PCB ground for optimal θ_JA = 70°C/W performance. No internal connection on Pin 1 (NC) - tie to OUT per datasheet recommendation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side current-limited power switch applications.

Compared with AP2191AFM-7, AP2181AFM-7 offers direct compatibility with active-low microcontroller outputs and matches EOL-replaced legacy designs; versus TCK1121B, it trades marginally higher R_DS(ON) for USB-specific protections essential in consumer-facing ports.

Availability

AP2181AFM-7 is available at Aetrix Electronics and suitable for USB self-powered hubs, laptop docking stations, and set-top box peripheral ports requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.

Supply support for AP2181AFM-7 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions for consumer, computing, and industrial markets.

The AP2181A/AP2191A product line was designed specifically for USB 2.0-compliant hot-swap power distribution, emphasizing integration of protection, precision current limiting, and compact packaging for space-constrained host and peripheral applications.

FAQ

What is the maximum continuous load current supported by AP2181AFM-7?

The AP2181AFM-7 is rated for 1.5A maximum continuous load current under recommended operating conditions (−40°C to +85°C ambient, proper PCB thermal design). Its 2.1A current limit provides headroom for transient surges, but sustained operation above 1.5A risks thermal shutdown due to power dissipation in the U-DFN2018-6 package.

Can AP2181AFM-7 be used in place of AP2191AFM-7?

Yes, AP2181AFM-7 is the designated replacement for the end-of-life AP2191AFM-7, differing only in enable polarity (active-low vs. active-high). All electrical specifications, protection features, pinout, and package are identical. System-level validation is required only for EN signal logic level alignment.

How does the 7ms FLG deglitch function impact system fault response?

The 7ms deglitch prevents FLG assertion during brief inrush events (e.g., 100µF output capacitor charging), ensuring only sustained over-current or thermal faults trigger host interrupt. This avoids spurious USB controller resets while preserving fast fault detection for genuine shorts lasting >7ms.

Is external capacitance required on the IN and OUT pins?

Yes: a 0.01–0.1µF ceramic capacitor is required between IN and GND, placed adjacent to the device. A minimum 10µF electrolytic capacitor is recommended on IN, and ≥120µF on OUT for heavy loads or low-temperature operation (<−30°C) to stabilize voltage and prevent false over-current trips.