Diodes Incorporated AP2204K-ADJTRG1

Overview

AP2204K-ADJTRG1 from Diodes Incorporated is an adjustable ultra-low dropout (ULDO) linear regulator IC designed for precision voltage regulation in space-constrained, battery-powered systems. It supports 1.24V–22V output via external resistor divider, delivers up to 150mA, features 100mV dropout at 100µA, 60dB PSRR at 1kHz, and operates across 2.6V–24V input. It is used in USB-powered portable instrumentation requiring stable low-noise bias.

For engineers reviewing the AP2204K-ADJTRG1 datasheet, AP2204K-ADJTRG1 pinout, AP2204K-ADJTRG1 application, or AP2204K-ADJTRG1 equivalent, key selection criteria include adjustable output range, thermal shutdown behavior, EN pin logic thresholds, ground current vs. load, and SOT-23-5 thermal resistance (θ_JA = 250°C/W).

Technical Context

The AP2204K-ADJTRG1 implements a high-voltage EPNP-based LDO architecture with internal 1.24V reference, error amplifier, and current-limit protection. Its ADJ pin accepts feedback from an external R1/R2 divider to set V_OUT = 1.24V × (1 + R1/R2), enabling precise programmability across its full 1.24V–22V range.

It integrates chip-enable logic with 2.0V "high" and 0.4V "low" thresholds, thermal shutdown at +150°C, and compatibility with low-ESR ceramic capacitors (1.0µF C_IN, 2.2µF C_OUT). Line regulation is 0.05% and load regulation is 0.5% over rated conditions.

Key Specifications

Pinout & Package

SOT-23-5 package: compact 2.9mm × 1.6mm footprint with exposed pad (connected to GND per datasheet Note 4), optimized for thermal dissipation in thin-profile portable PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1703T-3302E/MB and TLS850F0TESA1, the AP2204K-ADJTRG1 uniquely balances wide input range (2.6–24V), ultra-low dropout (100mV), and SOT-23-5 size-making it optimal for cost-sensitive, space-limited portable electronics where programmability and low IQ are essential.

Availability

AP2204K-ADJTRG1 is available at Aetrix Electronics and suitable for USB-powered instrumentation, portable medical monitors, industrial sensor nodes, and automotive accessory modules requiring stable component supply with RoHS 3 and green compliance.

Supply support for AP2204K-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 manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and the Americas.

The AP2204 series belongs to Diodes' high-voltage LDO product line, engineered specifically for USB, portable, and battery-powered applications demanding wide VIN range, low dropout, and low-noise performance in miniature packages.

FAQ

What is the minimum input voltage required for stable regulation with AP2204K-ADJTRG1?

The minimum recommended input voltage is the greater of 2.6V or V_OUT + 1V. For example, when configured for 5.0V output, VIN must be ≥6.0V to avoid dropout. Below this threshold, output voltage regulation degrades and ripple rejection falls significantly, as confirmed in the Recommended Operating Conditions table (DS37168 Rev. 6–3, p.5).

Can AP2204K-ADJTRG1 be used with ceramic output capacitors smaller than 2.2µF?

Yes, but stability must be verified per application. The datasheet specifies 2.2µF as the recommended value for guaranteed phase margin across temperature and load. Using lower values (e.g., 1.0µF) may reduce transient response margin and increase output overshoot; Diodes' application note AP2204-AN-01 confirms stable operation down to 1.0µF with careful PCB layout and ESR control.

How does the EN pin behave during power-up and brown-out conditions?

The EN pin has hysteresis-free TTL-compatible thresholds: output enables when V_EN ≥2.0V and disables when V_EN ≤0.4V. During slow-rising VIN, regulation begins only after both VIN exceeds V_OUT+1V *and* EN is asserted. No internal power-on-reset is provided-external sequencing or RC delay may be needed for controlled system startup.

Is the SOT-23-5 exposed pad electrically connected, and how should it be routed?

Yes-the exposed pad on the SOT-23-5 package is internally connected to GND (per datasheet Note 4). It must be soldered to a dedicated PCB copper pour tied to the main GND plane. This connection reduces θ_JA by ~30°C/W and improves thermal reliability under 150mA load; omitting it risks thermal shutdown during continuous operation.