Diodes Incorporated AP1084K33G-13

Overview

AP1084K33G-13 from Diodes Incorporated is a 5A low-dropout linear regulator in TO263-3L package, delivering fixed 3.3V output with ≤1.4V dropout at full load, ±1% load regulation (26–33 mV), and 1.25V internal reference voltage. It serves as a primary power supply for high-speed bus termination, 3.3V logic rails, and VGA card power delivery under 4.8–12V input.

For engineers reviewing the AP1084K33G-13 datasheet, AP1084K33G-13 pinout, AP1084K33G-13 application, or AP1084K33G-13 equivalent, this device is selected for stable 3.3V/5A regulation where thermal resistance (θJC = 3.5°C/W), fast transient response, and integrated thermal shutdown are critical design requirements.

Technical Context

The AP1084K33G-13 implements a three-terminal adjustable/fixed LDO architecture with a precision 1.25V bandgap reference and current-limited pass transistor. Its feedback loop uses an internal error amplifier comparing VOUT to VREF via the ADJ (GND) pin-bypassed entirely in fixed-mode operation.

Thermal protection activates at 150°C junction temperature, and stability relies on ≥10µF output capacitance (ESR 0.15–20Ω). Dropout behavior is characterized at ΔVOUT = 1% of nominal output, ensuring regulation down to VIN = VOUT + 1.4V across 0–5A load range.

Key Specifications

Pinout & Package

AP1084K33G-13 uses the TO263-3L (D²PAK) thermally enhanced surface-mount package with exposed metal tab electrically connected to VOUT for low thermal resistance and mechanical anchoring.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1084K33L-13, the G-suffix adds Br/Sb-free green molding compound for stricter environmental compliance; versus LD1085V33, AP1084K33G-13 delivers 67% higher current and maintains regulation at lower input margins-critical for dense, high-power PCBs.

Availability

AP1084K33G-13 is available at Aetrix Electronics and suitable for high-speed bus termination, VGA graphics card power, and industrial PLC I/O modules requiring stable component supply with guaranteed long-term sourcing.

Supply support for AP1084K33G-13 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, specializing in high-reliability power management, signal integrity, and protection solutions for industrial, computing, and communications markets.

The AP1084 product line targets high-current, low-noise linear regulation in space-constrained systems-designed specifically for 3.3V logic rails, bus termination, and graphics subsystems demanding fast transient response and thermal resilience.

FAQ

What is the minimum input voltage required for AP1084K33G-13 to regulate at full 5A load?

The AP1084K33G-13 requires VIN ≥ VOUT + 1.4V to maintain regulation at 5A, so minimum input is 4.7V. At lower inputs, dropout occurs and output collapses proportionally. This is verified in Electrical Characteristics Table (ΔVo = 1.3–1.4V at Io = 5.0A).

Can AP1084K33G-13 be used in adjustable mode despite its fixed 3.3V marking?

No-AP1084K33G-13 is factory-trimmed for fixed 3.3V output; the ADJ pin is internally grounded and not accessible for external resistor programming. Only AP1084K-XX (blank suffix) variants support adjustable operation using R1/R2 networks.

Is an input capacitor mandatory, and what value is recommended?

Yes-an input capacitor is mandatory to prevent VIN sag during load transients. Diodes recommends ≥10µF aluminum or tantalum capacitor close to the VIN pin; typical designs use 100µF (as shown in Figure 1 of DS31070 Rev. 9) with low-ESR construction.

How does the TO263-3L package's thermal performance compare to TO220-3L for this device?

TO263-3L offers θJC = 3.5°C/W versus TO220-3L's 3.5°C/W for the control circuitry path-but TO263-3L achieves lower θJA (60°C/W vs 78°C/W) due to superior PCB copper spreading, enabling higher continuous power in compact SMT layouts without added heatsinks.