Diodes Incorporated AP3433FNTR-G1

Overview

AP3433FNTR-G1 from Diodes Incorporated is a current-mode PWM synchronous buck DC-DC converter delivering 3A output with programmable 300kHz–2MHz switching frequency, integrated 45mΩ N-channel MOSFETs, and 0.827V ±3% reference voltage. It operates from 2.95V–5.5V input and targets point-of-load regulation in consumer electronics such as LCD displays and set-top boxes.

For engineers reviewing the AP3433FNTR-G1 datasheet, AP3433FNTR-G1 pinout, AP3433FNTR-G1 application, or AP3433FNTR-G1 equivalent, key selection criteria include its adjustable UVLO via EN pin, soft-start control via external capacitor on SS, power-good monitoring with 93–107% window, and thermal shutdown at +140°C.

Technical Context

The AP3433 employs peak current-mode control for cycle-by-cycle current limiting and fast transient response. Its dual-MOSFET architecture integrates high-side and low-side switches with typical R_DS(on) of 45mΩ each, enabling up to 94% efficiency at 3A load under 5V input.

Switching frequency is set either by an external resistor on RT/CLK (300kHz–2MHz) or synchronized to an external clock signal. The device supports soft-start into pre-biased outputs and features internal over-voltage, over-current, and thermal protection with hysteresis.

Key Specifications

Pinout & Package

AP3433FNTR-G1 is housed in a thermally enhanced QFN-3×3-16 package with exposed thermal pad. Pin 1 is marked with a dot; pins are arranged in counter-clockwise order from top-left when viewed from above.

Key Features

Applications

Availability

AP3433FNTR-G1 is available at Aetrix Electronics and suitable for set-top box power rails, LCD display core supply, and CPE equipment baseband supply requiring stable component supply despite end-of-life status.

Supply support for AP3433FNTR-G1 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 and manufacturing operations across Asia and the Americas.

The AP3433 belongs to Diodes' high-performance DC-DC converter product line, engineered for space-constrained consumer electronics requiring high efficiency, small solution size, and robust protection in 2.95–5.5V input environments.

FAQ

Is AP3433FNTR-G1 still in production?

No. Diodes Incorporated has officially discontinued the AP3433FNTR-G1, marking it "OBSOLETE – NO ALTERNATE PART" in its October 2018 datasheet. Aetrix Electronics maintains limited legacy stock for design continuity and last-time buy support, but no new production runs are planned.

What is the function of the RT/CLK pin?

The RT/CLK pin serves dual roles: connecting a resistor to GND sets switching frequency from 300kHz to 2MHz via internal oscillator; applying an external clock signal (300kHz–2MHz) synchronizes AP3433 to system timing, reducing EMI interference in noise-sensitive applications.

How does the AP3433 handle startup into a pre-biased output?

The AP3433 supports soft-start into pre-biased outputs by monitoring the SS pin voltage relative to internal reference. When V_SS exceeds 98% of V_REF, the controller begins switching only after confirming the output is not actively sinking current-preventing reverse current flow and potential damage.

Can the EN pin be used to adjust under-voltage lockout?

Yes. While the internal UVLO threshold is fixed at 2.6V, pulling EN below 1.2V disables the device. Adding a resistor divider from VIN to EN allows raising the effective turn-on threshold-for example, to match lithium battery discharge curves or avoid brown-out during input sag.