Diodes Incorporated AP1501A-33K5G-13

Overview

AP1501A-33K5G-13 from Diodes Incorporated is a fixed 3.3V, 5A non-synchronous PWM buck DC/DC converter in TO263-5 package, operating at 150kHz switching frequency with ±4% output voltage tolerance, thermal shutdown, and current-limit protection. It integrates the power switch and internal compensation, enabling high-efficiency step-down regulation for industrial power supplies and embedded systems requiring stable 3.3V rail generation from up to 40V input.

For engineers reviewing the AP1501A-33K5G-13 datasheet, AP1501A-33K5G-13 pinout, AP1501A-33K5G-13 application, or AP1501A-33K5G-13 equivalent, key selection considerations include its 5A continuous output capability, built-in 1.23V reference for feedback, ON/OFF shutdown control via logic-level SD pin, and thermal performance in TO263-5 with θ_JA = 37°C/W under standard PCB layout.

Technical Context

The AP1501A-33K5G-13 implements voltage-mode PWM control with a fixed 150kHz oscillator (±15%) and internal 1.23V reference. Its feedback loop uses the FB pin to regulate output by comparing a resistor-divided sample against this reference, eliminating external compensation components.

It features a monolithic 5A N-channel MOSFET switch with 1.5–1.6V saturation voltage at full load, thermal shutdown activation at ~125°C junction temperature, and cycle-by-cycle current limiting set at 5.5–6.5A peak. The SD pin provides TTL/CMOS-compatible enable/disable control with 0.6V low threshold and 2.0V high threshold.

Key Specifications

Pinout & Package

AP1501A-33K5G-13 is housed in a surface-mount TO263-5 (D²PAK) package with exposed metal tab electrically connected to GND for thermal and electrical grounding. The tab must be soldered to ≥0.8 in² of 2 oz copper on the PCB for adequate heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2596S-3.3/NOPB, AP1501A-33K5G-13 delivers +2A output headroom and integrated shutdown control; versus MP1584EN-LF-Z, it trades higher frequency for lower EMI and better thermal margin in TO263-5, making it preferable for industrial environments with strict EMC requirements.

Availability

AP1501A-33K5G-13 is available at Aetrix Electronics and suitable for industrial PLC power supplies, embedded system core rails, automotive body control modules, and point-of-load telecom converters requiring stable component supply with long lifecycle visibility.

Supply support for AP1501A-33K5G-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 power management, signal integrity, and protection solutions for industrial, computing, and automotive markets.

The AP1501A series belongs to Diodes' high-current DC/DC converter product line, designed specifically for cost-sensitive, high-reliability step-down applications where integration, thermal robustness, and wide input range are critical.

FAQ

What is the maximum recommended input voltage for AP1501A-33K5G-13?

The absolute maximum input voltage is +45V, but the recommended operating range is 4.5V to 40V. Operation above 40V risks exceeding internal transistor breakdown limits and degrading long-term reliability, even if thermal limits are maintained. For 48V telecom applications, a pre-regulator stage is advised.

Can AP1501A-33K5G-13 be used in adjustable-output configurations?

No - AP1501A-33K5G-13 is factory-trimmed for fixed 3.3V output and lacks the internal feedback divider needed for adjustment. Only the AP1501A-K5G-13 (ADJ) variant supports external resistor programming from 1.23V to 37V. Using the -33 version in adjustable mode will result in incorrect regulation.

How does the SD pin behave when left unconnected?

When the SD pin is left floating or tied to GND, the device remains enabled (ON). The SD pin is internally pulled up, so no external pull-up is required. To ensure reliable shutdown, drive SD to ≥2.0V with a logic-high source capable of sinking ≤25µA; do not rely on open-drain outputs without pull-up.

What thermal derating applies above 85°C ambient temperature?

With θ_JA = 37°C/W and T_J(MAX) = 125°C, maximum allowable ambient temperature at full 5A load is 88°C (125 – 5×37 = 88). Above 85°C ambient, output current must be linearly reduced: e.g., at 100°C ambient, max load drops to ~4.55A to maintain T_J ≤125°C under typical PCB copper layout.