Diodes Incorporated AP2127N-1.8TRG1

Overview

AP2127N-1.8TRG1 from Diodes Incorporated is a 300mA, 1.8V fixed-output CMOS low-dropout (LDO) regulator in SOT-23 package, featuring 170mV dropout at 300mA, ±2% output voltage accuracy, and 60μVRMS output noise - optimized for powering core logic and I/O rails in portable battery-powered systems including notebook CPUs and embedded controllers.

For engineers reviewing the AP2127N-1.8TRG1 datasheet, AP2127N-1.8TRG1 pinout, AP2127N-1.8TRG1 application, or AP2127N-1.8TRG1 equivalent, key selection criteria include dropout performance under 300mA load, 68dB PSRR at 1kHz, thermal shutdown threshold at +165°C, and compatibility with 1μF ceramic input/output capacitors.

Technical Context

This LDO employs a PMOS pass transistor architecture enabling ultra-low dropout and fast transient response. Its internal 0.8V reference feeds a precision error amplifier that regulates output against line, load, and temperature variations within ±100ppm/°C drift.

The device integrates active shutdown control with 0.1μA standby current, auto-discharge MOSFET (R_DS(ON) = 60Ω), over-temperature protection (+165°C trip with +30°C hysteresis), and short-circuit current limiting (50mA typical).

Key Specifications

Pinout & Package

SOT-23 package (3-pin, 2.9mm × 1.6mm × 1.1mm) with exposed pad not present; thermal resistance θ_JA = 180°C/W. Pin 1 = GND, Pin 2 = V_OUT, Pin 3 = V_IN.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with AP2127N-1.8TRG1, AP2112K-1.8TRG1 offers double the current capacity at the cost of larger footprint and added pin complexity, while MCP1700T-1802E/TT trades off shutdown control and noise performance for extreme quiescent current reduction - making each suitable for distinct power architecture priorities.

Availability

AP2127N-1.8TRG1 is available at Aetrix Electronics and suitable for notebook computers, industrial sensor nodes, wearable health monitors, and mobile baseband processor power requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AP2127N-1.8TRG1 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 semiconductor company specializing in discrete, analog, and mixed-signal ICs for power management, signal integrity, and connectivity applications.

The AP2127 Series belongs to Diodes' high-performance LDO portfolio designed specifically for noise-sensitive, battery-constrained portable electronics requiring ultra-low dropout, sub-100μA quiescent current, and robust thermal protection.

FAQ

What is the minimum input voltage required for AP2127N-1.8TRG1 to maintain regulation?

The AP2127N-1.8TRG1 requires a minimum input voltage of 2.5V per its recommended operating conditions. At 300mA load, the dropout voltage is 600mV max, so regulation is maintained down to VIN = 2.4V - however, operation below 2.5V violates datasheet specifications and may compromise output accuracy, PSRR, and thermal margin.

Can AP2127N-1.8TRG1 be used with aluminum polymer capacitors instead of ceramic?

No - the AP2127N-1.8TRG1 is explicitly characterized and stabilized for use with low-ESR ceramic capacitors (X7R/X5R, ≥1μF). Aluminum polymer capacitors typically exhibit higher ESR and insufficient high-frequency impedance, which can cause instability, oscillation, or degraded transient response per the datasheet's stability region plots.

Does AP2127N-1.8TRG1 require an external pull-up resistor on the shutdown pin?

No - the shutdown pin has an internal 3MΩ pull-down resistor. When left unconnected, the pin defaults to logic low, disabling the regulator. To enable operation, apply ≥1.5V to the shutdown pin; no external pull-up is needed unless open-drain control logic is used.

How does the auto-discharge function behave during normal operation?

The auto-discharge MOSFET (60Ω R_DS(ON)) is inactive during normal operation. It engages only when the shutdown pin is driven low, creating a controlled discharge path from V_OUT to GND. This safely bleeds stored charge from output capacitors within milliseconds, preventing back-powering of upstream circuitry during power-down sequences.