Diodes Incorporated AP2128K-5.2TRG1

Overview

AP2128K-5.2TRG1 from BCD Semiconductor Manufacturing Limited is a fixed-output 5.2V, 300mA CMOS low-dropout linear regulator in SOT-23-5 package, featuring 140mV dropout at full load, ±2% output voltage accuracy, 60µV_RMS output noise, and 68dB PSRR at 1kHz. It delivers stable power to precision analog rails in notebook computers and motherboard VRM post-regulation stages.

For engineers reviewing the AP2128K-5.2TRG1 datasheet, AP2128K-5.2TRG1 pinout, AP2128K-5.2TRG1 application, or AP2128K-5.2TRG1 equivalent, key selection criteria include dropout performance at 5.2V output, soft-start timing (50µs), shutdown logic thresholds (0–0.4V low / 1.5–6V high), and compatibility with 1µF ceramic input/output capacitors.

Technical Context

The AP2128K-5.2TRG1 implements a CMOS-based LDO architecture with P-channel pass transistor, internal 0.8V reference, and integrated thermal shutdown (165°C) with 30°C hysteresis. Its feedback loop is internally compensated for stability with 1µF ceramic capacitors.

Shutdown control is active-high, enabling fast turn-off with 0.1µA standby current; the VOUT discharge MOSFET (R_DS(ON) = 60Ω) ensures rapid output decay when disabled. Line regulation is 0.06%/V and load regulation is 0.6%/A over full operating range.

Key Specifications

Pinout & Package

SOT-23-5 package: 2.82 × 2.65 × 1.30 mm body, 0.95 mm lead pitch, gull-wing leads, 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 MCP1700T-5002E/TT and XC6206P522MR-G, AP2128K-5.2TRG1 uniquely combines 5.2V precision, 140mV dropout, integrated shutdown with discharge, and verified 54dB PSRR at 10kHz-making it the sole choice for noise-critical, enable-controlled 5.2V rails in space-constrained designs.

Availability

AP2128K-5.2TRG1 is available at Aetrix Electronics and suitable for notebook computers, motherboard power delivery, industrial sensor signal chains, and embedded FPGA configuration requiring stable component supply, consistent parametric performance, and RoHS-compliant green packaging.

Supply support for AP2128K-5.2TRG1 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, LED drivers, and mixed-signal solutions for consumer, computing, and industrial markets.

The AP2128 series targets ultra-low-noise, high-PSRR LDO applications in battery-powered and thermally constrained systems-designed specifically for post-regulation of DC/DC outputs in portable computing and precision analog subsystems.

FAQ

What is the minimum input voltage required for AP2128K-5.2TRG1 to regulate 5.2V output?

The AP2128K-5.2TRG1 requires a minimum input voltage of 5.34V to sustain 5.2V output at 300mA load, based on its 140mV dropout specification. Below this, output voltage collapses linearly with input; operation down to 2.5V input is supported only for lower output voltages (e.g., 1.0–3.3V versions).

Can AP2128K-5.2TRG1 be used with aluminum polymer capacitors instead of ceramic?

No-AP2128K-5.2TRG1 is explicitly characterized and stabilized for use with low-ESR ceramic capacitors (≥1µF X5R/X7R). Aluminum polymer capacitors exhibit higher ESR and phase shift that may cause instability or oscillation; ceramic remains mandatory per datasheet Figure 40 and Section 6.1.

Does the NC pin require any PCB routing or grounding?

The NC pin in AP2128K-5.2TRG1 (fixed-output version) is internally unconnected and electrically isolated. It must be left floating-no PCB trace, solder mask opening, or grounding is required or recommended. Routing to GND may introduce parasitic coupling and is not specified in the datasheet.

How does thermal shutdown behave during transient overload conditions?

Thermal shutdown activates at 165°C junction temperature with 30°C hysteresis, forcing output disable until die cools to ≤135°C. During short-duration overloads (<100ms), the 150°C/W θ_JC and small SOT-23-5 thermal mass allow brief operation above 300mA without triggering shutdown-verified in Figure 11 and Absolute Maximum Ratings Table.