Diodes Incorporated AP65353SP-13

Overview

AP65353SP-13 from Diodes Incorporated is a synchronous step-down DC-DC converter IC delivering 3A output current, 18V max input, and 650kHz pseudo-constant switching frequency using adaptive constant-on-time (aCOT) control. It integrates high- and low-side NMOS power switches (90mΩ/57mΩ), supports CCM/DCM transition, and regulates down to 0.765V with ±1.5% feedback accuracy - deployed in flat-screen TV main 1.05V CPU core rails.

For engineers reviewing the AP65353SP-13 datasheet, AP65353SP-13 pinout, AP65353SP-13 application, or AP65353SP-13 equivalent, key selection criteria include its adaptive on-time transient response, SO-8EP thermal performance (θJA = 38.56°C/W), soft-start programmability via external capacitor, and compatibility with ultra-low-ESR ceramic or polymer output capacitors.

Technical Context

The AP65353SP-13 implements an adaptive constant-on-time (aCOT) control architecture that calculates per-cycle on-time as t_ON ∝ V_OUT/V_IN, enabling pseudo-fixed 650kHz operation without an internal oscillator. Its digital control logic includes min-off-time clamping (260ns typ) and seamless CCM-to-DCM transition at light load.

Internal protection includes non-latching UVLO (3.65V turn-on, 320mV hysteresis), thermal shutdown at 150°C (25°C hysteresis), overvoltage protection at 115–125% of V_OUT, and cycle-by-cycle overcurrent detection using low-side R_DS(ON) sensing with temperature-compensated trip threshold.

Key Specifications

Pinout & Package

AP65353SP-13 is housed in an SO-8EP (exposed pad) package optimized for thermal dissipation and board-level reliability in space-constrained consumer power supplies.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter applications.

Compared with MP2315DJ-LF-Z and RT7297CGJ8F, the AP65353SP-13 delivers superior light-load efficiency via DCM operation, faster transient response through adaptive on-time control, and higher thermal capability due to SO-8EP's lower θJA - making it optimal for consumer SoC core rails demanding both dynamic performance and standby power savings.

Availability

AP65353SP-13 is available at Aetrix Electronics and suitable for flat-screen TV sets, gaming consoles, and set-top boxes requiring stable component supply, long-term manufacturability, and RoHS 3-compliant packaging.

Supply support for AP65353SP-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 semiconductor manufacturer specializing in discrete, analog, and mixed-signal ICs for consumer, computing, communications, and industrial markets.

The AP65353 belongs to Diodes' high-efficiency DC-DC converter product line, engineered specifically for low-voltage, high-current regulation in digital TVs, monitors, and multimedia SoC platforms where fast transient response and thermal robustness are critical.

FAQ

What input and output capacitors are recommended for AP65353SP-13 in a 1.05V/3A design?

For a 1.05V/3A application, use a 22μF X5R/X7R ceramic capacitor (1206 or larger) at VIN with ≤10mΩ ESR, and two parallel 22μF ceramics at VOUT (total 44μF) with combined ESR <5mΩ. The datasheet specifies C1 = 20μF and C2 = 44μF in the typical application circuit, and confirms ceramic capacitors are mandatory for stability with adaptive COT control.

How is the output voltage set, and what resistor tolerance is required for ±1.5% regulation?

Output voltage is set via a resistive divider from VOUT to FB, with V_FB = 0.765V. For 1.05V output, R1 = 8.25kΩ and R2 = 22.1kΩ (per Table 1). To maintain ±1.5% total output error, use 0.5% tolerance resistors - the FB bias current (±0.1μA) contributes <0.1% error only if R1+R2 ≤ 250kΩ, which this divider satisfies.

Does AP65353SP-13 support forced PWM mode, or is DCM operation mandatory at light load?

The AP65353SP-13 does not support forced PWM mode; it automatically enters discontinuous conduction mode (DCM) below ~300mA load to improve light-load efficiency. This behavior is inherent to its adaptive COT architecture and cannot be disabled. DCM operation reduces switching frequency and minimizes inductor current reversal, achieving <10μA quiescent current in shutdown and ~0.75mA in active light-load states.

What is the maximum achievable output current with SO-8EP package at +85°C ambient?

At +85°C ambient, the SO-8EP package supports up to 3A continuous output current when mounted on a 1"×1" FR-4 PCB with 2oz copper and full PGND pad connection. Thermal calculations using θ_JA = 38.56°C/W and P_D ≈ 0.45W (at 12V→1.05V/3A, 92% efficiency) yield ΔT ≈ 17.4°C, resulting in T_J ≈ 102°C - safely below the 125°C max operating junction temperature.