Diodes Incorporated AP1086D33L-U

Overview

AP1086D33L-U from Diodes Incorporated is a fixed-output 3.3V, 1.5A low dropout (LDO) linear regulator in TO220-3L package, featuring 1.4V maximum dropout at full load, ±1% output voltage tolerance at 10mA, and built-in thermal shutdown and current limiting. It delivers stable 3.3V supply for high-speed bus termination, VGA card power rails, and low-current logic systems with 4.8–12V input.

For engineers reviewing the AP1086D33L-U datasheet, AP1086D33L-U pinout, AP1086D33L-U application, or AP1086D33L-U equivalent, key selection criteria include dropout voltage under 1.4V at 1.5A, guaranteed load regulation ≤33mV across 0–1.5A, thermal resistance θ_JA = 86°C/W (TO220-3L), minimum 10µF output capacitance requirement, and fixed 3.3V output without external resistors.

Technical Context

The AP1086D33L-U implements a standard bandgap reference (1.25V) with error amplifier and PNP pass transistor architecture, enabling fixed 3.3V output via internal resistor divider. Its fast transient response is achieved through internal frequency compensation optimized for ≥10µF tantalum or aluminum electrolytic output capacitors.

Operation requires VIN ≥ VOUT + 1.4V (i.e., ≥4.7V) to maintain regulation; line regulation is specified at ≤0.2% over VIN = VOUT+1.5V to 12V, and load regulation is ≤33mV from 0 to 1.5A at TJ = 25°C with VIN = 5V.

Key Specifications

Pinout & Package

AP1086D33L-U uses the TO220-3L package: thermally enhanced plastic case with isolated tab connected to VOUT, 3-pin vertical mounting configuration, and 86°C/W junction-to-ambient thermal resistance without heatsink.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM1117MPX-3.3/NOPB and LD1086V33, AP1086D33L-U offers tighter 3.3V tolerance (±1%), lower dropout (1.4V), and guaranteed 1.5A capability in a RoHS-compliant TO220-3L package - making it optimal for space-tolerant, high-current 5V-input applications where precision and thermal margin are critical.

Availability

AP1086D33L-U is available at Aetrix Electronics and suitable for high-speed bus termination, VGA card power rails, and low-current logic supply applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AP1086D33L-U 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 power management, signal integrity, and protection devices for consumer, industrial, and computing markets.

The AP1086 series belongs to Diodes' LDO regulator product line, engineered specifically for low-voltage IC supply in high-speed digital systems - emphasizing tight output tolerance, fast transient response, and robust thermal protection in cost-sensitive applications.

FAQ

What is the minimum input voltage required for AP1086D33L-U to regulate at 3.3V?

The AP1086D33L-U requires VIN ≥ VOUT + 1.4V = 4.7V to maintain regulation at full 1.5A load. At lighter loads, dropout decreases slightly, but 4.8V is the guaranteed minimum per datasheet conditions for 3.3V output. Input below this threshold causes output to track VIN minus dropout, losing regulation.

Can AP1086D33L-U be used without an output capacitor?

No. A minimum 10µF aluminum or tantalum capacitor is mandatory between VOUT and GND for stability and transient response. Omitting it risks oscillation, excessive output ripple, and failure to meet load regulation or dropout specifications. Ceramic capacitors alone are insufficient due to ESR requirements.

How does the TO220-3L package's tab connection affect PCB layout?

The tab is electrically connected to VOUT, so the mounting pad must be routed to the 3.3V net - not GND or floating. This enables direct thermal conduction to a heatsink while avoiding short circuits. Use isolation slots or thermal relief if connecting to internal 3.3V planes to manage solder wicking during reflow.

Is AP1086D33L-U suitable for automotive applications?

AP1086D33L-U is not AEC-Q100 qualified and operates only from 0°C to 125°C junction temperature. While it may function in cabin-temperature automotive modules, Diodes does not specify it for under-hood or safety-critical systems. For automotive use, select AEC-Q100 qualified alternatives like AP7361-C or AZ1086 series with extended temp and qualification support.