Diodes Incorporated AP2161AW-7

Overview

AP2161AW-7 from Diodes Incorporated is a single-channel, active-low enable, current-limited high-side power switch optimized for USB 2.0 hot-swap applications. It delivers 1.5A accurate current limiting, 95mΩ on-resistance at 5V, 0.6ms typical rise time, and integrated short-circuit/thermal protection with 7ms deglitch on the open-drain FLG output. Used in laptop USB ports and docking stations to prevent inrush damage and report over-current faults.

For engineers reviewing the AP2161AW-7 datasheet, AP2161AW-7 pinout, AP2161AW-7 application, or AP2161AW-7 equivalent, key selection criteria include enable polarity (active-low), thermal shutdown threshold (140°C), UVLO trip (1.9V typ), reverse current blocking capability, and SOT25 package compatibility with space-constrained USB load-switch designs.

Technical Context

The AP2161AW-7 integrates a low-R_DS(ON) N-channel MOSFET with precision current-sense FET architecture, enabling accurate 1.5A current limiting without external sense resistors. Its internal UVLO circuit disables the switch below 1.9V input, ensuring safe hot-plug sequencing.

It features an open-drain FLG output with 7ms blanking time to suppress false fault reporting during capacitive load turn-on transients, and implements thermal shutdown with 25°C hysteresis to cycle off/on under sustained overload - all without requiring external components for basic protection.

Key Specifications

Pinout & Package

AP2161AW-7 is supplied in the SOT25 (SOT-23-5) package - a 5-pin, surface-mount, lead-free, RoHS-compliant outline with exposed pad for thermal enhancement. Pin 1 is OUT, Pin 2 is IN, Pin 3 is EN (active-low), Pin 4 is FLG (open-drain), and Pin 5 is GND. The exposed pad must be soldered to PCB ground for optimal thermal performance but is not an electrical ground conduction path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP2161AW-7, AP2162AW-7 offers identical protection and performance with reversed enable polarity, while TPS2051BDBVR trades integrated blanking and reverse blocking for vendor-specific qualification - making AP2161AW-7 optimal for compact, self-contained USB load switching where board space and reliability are prioritized.

Availability

AP2161AW-7 is available at Aetrix Electronics and suitable for USB 2.0 port protection, laptop docking station power control, and set-top box peripheral interfaces requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for AP2161AW-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 AP2161A/AP2171A product line was designed specifically for USB 2.0-compliant hot-swap power distribution, emphasizing integration of protection features, minimal external component count, and thermal resilience in space-constrained portable electronics.

FAQ

What is the function of the FLG pin on AP2161AW-7?

The FLG pin is an open-drain fault indicator that asserts low during over-current or over-temperature conditions. It incorporates a built-in 7ms deglitch timer to ignore transient inrush currents from output capacitors, eliminating the need for external RC filtering. The pin remains low until both fault conditions are cleared, enabling direct connection to microcontroller interrupt inputs for real-time USB port monitoring.

Does AP2161AW-7 support reverse current blocking, and how is it implemented?

Yes, AP2161AW-7 provides inherent reverse current blocking when disabled: its internal N-channel MOSFET structure prevents current flow from OUT to IN due to body diode orientation and gate drive cutoff. This eliminates the need for an external blocking diode in USB host applications, reducing forward voltage drop, power loss, and board area - especially critical in battery-powered devices where efficiency and thermal management are paramount.

Can AP2161AW-7 operate reliably at 2.7V input, and what happens near UVLO threshold?

Yes, AP2161AW-7 operates down to 2.7V input and remains fully functional above its 1.9V UVLO threshold. When VIN drops below ~1.9V (with 0.3V hysteresis), the internal switch forcibly turns off regardless of EN state, preventing unstable operation or partial conduction. This ensures clean power removal during brown-out events and guarantees safe hot-unplug behavior in USB systems without requiring external supervision circuitry.

How does thermal protection behave under sustained short-circuit conditions?

Under sustained short-circuit, AP2161AW-7 first enters constant-current limiting at ~1.5A, then heats up until junction temperature reaches ~140°C, triggering thermal shutdown. The device cycles on/off with ~25°C hysteresis - turning back on only after cooling to ~115°C. During each on-cycle, the FLG pin stays low, providing continuous fault signaling to the host controller without latch-up, enabling graceful system-level error handling and recovery.