Diodes Incorporated AP2127K-ADJTRG1

Overview

AP2127K-ADJTRG1 from Diodes Incorporated is a 300mA, adjustable-output CMOS low-dropout (LDO) regulator in SOT-23-5 package, delivering 0.8V to 5.5V output with ±2% accuracy, 60μA typical quiescent current, and 60μV_RMS output noise. It integrates shutdown control, soft-start (50μs), auto-discharge (60Ω R_DS(ON)), and thermal/overcurrent protection-designed for precision power rails in portable and noise-sensitive analog systems.

For engineers reviewing the AP2127K-ADJTRG1 datasheet, AP2127K-ADJTRG1 pinout, AP2127K-ADJTRG1 application, or AP2127K-ADJTRG1 equivalent, key selection criteria include adjustable output range (0.8–5.5V), ultra-low noise performance, compatibility with 1μF ceramic input/output capacitors, and integrated shutdown with active discharge-critical for battery-powered instrumentation and RF subsystems.

Technical Context

The AP2127K-ADJTRG1 uses a CMOS pass transistor architecture with internal 0.8V reference and feedback loop via ADJ pin, enabling precise external resistor-divider programming of output voltage. Its control logic includes dedicated Shutdown input (1.5V high threshold, 0.5V low threshold) and thermal shutdown at +165°C with +30°C hysteresis.

It achieves high PSRR (68dB @ 1kHz, 54dB @ 10kHz) through optimized error amplifier design and stable operation with low-ESR 1μF X7R/X5R MLCCs. The integrated 60Ω discharge MOSFET enables rapid VOUT decay during shutdown, reducing system-level power sequencing complexity.

Key Specifications

Pinout & Package

SOT-23-5 package: 2.9mm × 1.6mm × 1.1mm body with exposed thermal pad (connected to GND for optimal thermal performance). RoHS-compliant, halogen-free, lead-free construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1826T-ADJ/DC and TLS850B2LF33, AP2127K-ADJTRG1 uniquely combines adjustable output, 60μA IQ, 60μV_RMS noise, and integrated 60Ω discharge-making it optimal for space-constrained, battery-sensitive, and noise-critical applications where programmability and fast shutdown response are essential.

Availability

AP2127K-ADJTRG1 is available at Aetrix Electronics and suitable for portable medical sensors, industrial data acquisition modules, wearable fitness trackers, and automotive infotainment subsystems requiring stable component supply with guaranteed long-term sourcing.

Supply support for AP2127K-ADJTRG1 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 solutions for power management, signal integrity, and connectivity applications.

The AP2127 Series targets low-noise, low-quiescent-current LDO regulation in battery-powered and noise-sensitive electronics-emphasizing CMOS process advantages for precision, efficiency, and small-footprint integration.

FAQ

What is the minimum input voltage required for AP2127K-ADJTRG1 to regulate a 3.3V output?

The AP2127K-ADJTRG1 requires VIN ≥ VOUT + VDROP. At 300mA load and VOUT = 3.3V, typical dropout is 170mV, so minimum VIN is 3.47V. For reliable operation across temperature and tolerance, Diodes specifies 2.5V minimum VIN for outputs ≤1.8V and recommends VIN ≥ VOUT + 1V for outputs ≥2.5V per datasheet conditions.

Can AP2127K-ADJTRG1 be used with a 10μF output capacitor?

Yes-AP2127K-ADJTRG1 is stable with ceramic capacitors ≥1μF and low ESR. A 10μF X7R MLCC improves transient response and reduces output undershoot/overshoot during load steps, especially at higher currents. No compensation changes are needed; the device's internal design accommodates this capacitance range.

How does the ADJ pin function in the AP2127K-ADJTRG1?

The ADJ pin connects to the midpoint of an external resistor divider (R1–R2) between VOUT and GND. The internal 0.8V reference compares against the ADJ node voltage, adjusting the pass transistor to maintain VOUT = 0.8V × (1 + R1/R2). R2 is recommended between 5kΩ and 200kΩ; feed-forward capacitor between ADJ and VOUT enhances stability for certain ratios.

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

Yes-the exposed thermal pad is internally connected to GND. It must be soldered to a GND copper pour on the PCB for optimal thermal performance and electrical stability. Diodes' datasheet specifies θ_JA = 250°C/W for SOT-23-5 with minimal copper; thermal resistance improves significantly with proper pad connection and thermal vias.