Diodes Incorporated AP2128K-3.0TRG1

Overview

AP2128K-3.0TRG1 from BCD Semiconductor is a fixed-output 3.0V, 300mA CMOS low-dropout regulator with 170mV dropout at full load, ±2% output accuracy, and 60µV_rms output noise. It operates from 2.5V to 6V input, features active shutdown (0.1µA standby), soft-start (50µs), and thermal/overcurrent protection-designed for powering noise-sensitive analog rails in portable computing and motherboard voltage domains.

For engineers reviewing the AP2128K-3.0TRG1 datasheet, AP2128K-3.0TRG1 pinout, AP2128K-3.0TRG1 application, or AP2128K-3.0TRG1 equivalent, key selection criteria include ultra-low noise performance, SOT-23-5 footprint compatibility, fixed 3.0V output stability across -40°C to 85°C, and support for ceramic capacitors as small as 1µF on both input and output.

Technical Context

The AP2128K-3.0TRG1 implements a PMOS pass transistor architecture enabling low dropout and high PSRR (68dB @ 1kHz). Its internal reference (0.8V) and error amplifier regulate output via direct feedback-no external resistors required in fixed-voltage mode. Shutdown control is logic-compatible (0–0.4V low, 1.5–6V high) and activates an internal 60Ω discharge path.

It integrates overtemperature protection (165°C trip, 30°C hysteresis) and short-circuit current limiting (50mA typical), with line/load regulation of 0.06%/V and 0.6%/A respectively. The device maintains stable operation with 1µF ceramic capacitors and exhibits excellent thermal resistance (θ_JA = 250°C/W, θ_JC = 150°C/W).

Key Specifications

Pinout & Package

SOT-23-5 package: 2.95mm × 1.70mm × 1.30mm body, 0.95mm lead pitch, RoHS-compliant green finish (G1 suffix).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output LDO applications.

Compared with AP2128K-3.0TRG1, AP2112K-3.0TRG1 trades current capability and dynamic performance for lower cost, while XC6206P302MR sacrifices shutdown control and PSRR for simpler integration-making AP2128K-3.0TRG1 optimal for noise-critical, power-gated systems requiring full-feature LDO control.

Availability

AP2128K-3.0TRG1 is available at Aetrix Electronics and suitable for notebook computers, motherboard I/O rails, and industrial sensor nodes requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant green packaging.

Supply support for AP2128K-3.0TRG1 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

BCD Semiconductor Manufacturing Limited is a Shanghai-based analog IC designer specializing in high-performance power management and mixed-signal solutions for consumer, industrial, and communications markets.

The AP2128 series targets battery-powered and noise-sensitive applications, emphasizing ultra-low noise, fast transient response, and minimal external component count for compact, reliable power delivery.

FAQ

What is the minimum input voltage required for stable 3.0V output at 300mA?

The AP2128K-3.0TRG1 requires VIN ≥ 3.17V (3.0V + 170mV dropout) for full 300mA output. At lower input voltages, output current capability degrades linearly per Figure 8; operation below 2.5V violates absolute maximum ratings and risks malfunction.

Can AP2128K-3.0TRG1 be used with tantalum or aluminum electrolytic capacitors?

No-AP2128K-3.0TRG1 is optimized for low-ESR ceramic capacitors (≥1µF X5R/X7R). Tantalum or aluminum electrolytics exhibit higher ESR and ESL, which degrade PSRR, cause instability, and increase output ripple beyond datasheet specifications.

Does the SHUTDOWN pin require a pull-up resistor?

No external pull-up is needed. The SHUTDOWN pin has an internal 3MΩ pull-down resistor. Driving it high (≥1.5V) enables regulation; leaving it floating defaults to disabled state due to the pull-down, ensuring fail-safe power-off behavior.

How does thermal shutdown behave during sustained overload?

At 165°C junction temperature, thermal shutdown disables the pass transistor and discharges VOUT via the 60Ω internal MOSFET. After cooling by 30°C (to ≤135°C), the device automatically recovers-no manual reset is required, enabling robust self-protection in enclosed or high-ambient environments.