Diodes Incorporated AP2127K-1.8TRG1

Overview

AP2127K-1.8TRG1 from Diodes Incorporated is a 300mA, 1.8V fixed-output CMOS low-dropout (LDO) regulator in SOT-23-5 package, featuring 140mV dropout at 300mA, ±2% output voltage accuracy, and 60μVRMS output noise-designed for powering noise-sensitive analog circuitry in portable battery-powered systems such as notebook CPU core logic and embedded microcontroller I/O rails.

For engineers reviewing the AP2127K-1.8TRG1 datasheet, AP2127K-1.8TRG1 pinout, AP2127K-1.8TRG1 application, or AP2127K-1.8TRG1 equivalent, key selection criteria include dropout performance under 300mA load, thermal shutdown behavior at +165°C, soft-start timing of 50μs, and compatibility with 1μF ceramic input/output capacitors without external compensation.

Technical Context

The AP2127K-1.8TRG1 employs a PMOS pass transistor architecture enabling ultra-low dropout and high PSRR (68dB @ 1kHz), with internal reference voltage (0.8V) and precision bandgap regulation ensuring stable 1.8V output across -40°C to +85°C ambient temperature. Its shutdown control pin enables active-low enable functionality with 0.1μA standby current.

Thermal protection activates at +165°C with +30°C hysteresis, and short-circuit current limiting clamps output to 50mA during fault conditions. The integrated auto-discharge MOSFET (R_DS(ON) = 60Ω) rapidly discharges VOUT when disabled, preventing hold-up voltage in power sequencing applications.

Key Specifications

Pinout & Package

SOT-23-5 package with exposed thermal pad (connected to GND for optimal thermal performance); 5-pin surface-mount footprint compatible with standard reflow profiles and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-1802E/TT and XC6206P182MR-G, the AP2127K-1.8TRG1 uniquely combines 300mA capability, 140mV dropout, active shutdown with auto-discharge, and SOT-23-5 pinout-making it optimal for sequenced, noise-sensitive, battery-powered systems requiring both performance and functional integration.

Availability

AP2127K-1.8TRG1 is available at Aetrix Electronics and suitable for notebook computers, datacom modules, and industrial sensor nodes requiring stable component supply with guaranteed long-term manufacturability and RoHS/Green compliance.

Supply support for AP2127K-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 manufacturer specializing in discrete, analog, and mixed-signal solutions, with emphasis on power management, signal integrity, and connectivity products for industrial, computing, and consumer markets.

The AP2127 series belongs to Diodes' high-performance LDO portfolio, engineered specifically for battery-powered and noise-sensitive applications demanding ultra-low dropout, low quiescent current, and exceptional PSRR across wide frequency bands.

FAQ

What is the minimum input voltage required for stable 1.8V output at 300mA?

The AP2127K-1.8TRG1 requires VIN ≥ 1.94V to maintain regulation at 300mA load, based on its 140mV maximum dropout specification. For reliable operation across temperature and process variation, Diodes recommends VIN ≥ 2.0V-ensuring margin against line regulation drift and PCB trace resistance losses.

Can the AP2127K-1.8TRG1 be used with ceramic capacitors smaller than 1μF?

No-Diodes specifies 1μF minimum for both CIN and COUT using X5R/X7R MLCCs to guarantee stability across -40°C to +85°C. Using <1μF risks oscillation or degraded transient response, as confirmed by stability testing in DS36478 Rev. 7 Section 12.

Does the Shutdown pin require a pull-up resistor?

Yes-a 100kΩ pull-up to VIN is recommended to ensure reliable high-state initialization during power-up. The shutdown threshold is 1.5V (min) for logic high and 0.5V (max) for logic low; an external pull-up prevents floating states that could cause unintended disable.

Is the exposed thermal pad on the SOT-23-5 package electrically connected?

Yes-the exposed pad is internally connected to GND and must be soldered to a PCB ground plane for thermal performance and electrical integrity. Diodes specifies θ_JA = 250°C/W for the SOT-23-5 package assuming proper pad connection and 1-in² copper area.