Diodes Incorporated AP3105KTR-G1

Overview

AP3105KTR-G1 from Diodes Incorporated is a cost-effective, green-mode current-mode PWM controller for offline AC-DC power supplies. It delivers 65 kHz nominal switching frequency with ±6% dithering, burst-mode operation down to 20 kHz to suppress audible noise, and cycle-by-cycle overcurrent protection (OCP) with 0.85 V current-sense threshold. Used in notebook adapters and LCD monitor auxiliary supplies.

For engineers reviewing the AP3105KTR-G1 datasheet, AP3105KTR-G1 pinout, AP3105KTR-G1 application, or AP3105KTR-G1 equivalent, key selection criteria include UVLO thresholds (15.5 V turn-on / 8.6 V turn-off), adjustable skip mode via external resistor, integrated slope compensation, and latch-type OTP/OVP triggered by CTRL pin voltage thresholds (0.5 V low / 2.5 V high).

Technical Context

The AP3105KTR-G1 implements fixed-frequency current-mode control with built-in 250 ns leading-edge blanking (LEB) and internal slope compensation to ensure stability above 50% duty cycle. Its oscillator includes frequency jitter (±6%) to reduce EMI peaks and supports automatic frequency foldback under light load.

Protection architecture integrates multiple independent comparators: VCC OVP (28.5 V), OLP (auto-recoverable), FOCP (1.8 V threshold, ~100 ns delay), and pin-fault detection for floating SENSE/FB or shorted CTRL. The CTRL pin enables user-configurable latch protection with dual-threshold triggering (0.5 V / 2.5 V) and 32 ms delay for hiccup-mode OLP.

Key Specifications

Pinout & Package

AP3105KTR-G1 is housed in a RoHS-compliant SOT-23-6 (K package) with 2.82 mm × 2.95 mm footprint and 1.45 mm height. Thermal resistance θ_JA is 250 °C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PWM controller applications.

Compared with AP3103KTR-G1, AP3105KTR-G1 adds latch protection and VCC maintain for robustness in thermally constrained adapters; versus ICE2QS03G, it trades HV starter integration for lower standby power and superior acoustic performance via burst-mode dithering.

Availability

AP3105KTR-G1 is available at Aetrix Electronics and suitable for AC-DC notebook adapters, ATX auxiliary power supplies, and set-top box power supplies requiring stable component supply, RoHS/Green compliance, and long-term lifecycle support.

Supply support for AP3105KTR-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 centers across Asia and manufacturing in China, Taiwan, and Malaysia.

The AP3105 product line targets cost-sensitive, energy-efficient offline SMPS designs-specifically optimizing for low standby power, audible-noise-free operation, and comprehensive fault protection in consumer and computing power supplies.

FAQ

What is the purpose of the CTRL pin on AP3105KTR-G1?

The CTRL pin provides configurable latch protection: pulling it below 0.5 V or above 2.5 V triggers permanent shutdown until AC input is cycled. Connecting an NTC thermistor between CTRL and GND enables thermal shutdown, while leaving it open disables latch functionality entirely. This pin does not affect normal PWM operation when within 0.5–2.5 V.

How does AP3105KTR-G1 achieve <100 mW standby power?

It combines three mechanisms: (1) burst-mode operation at 20–30 kHz to eliminate audible noise while minimizing switching loss, (2) 5 µA typical startup current enabling high-value startup resistors that dissipate <15 mW at 265 VAC, and (3) VCC maintain mode that sustains regulation without full PWM cycling during light loads.

Can AP3105KTR-G1 replace AP3103KTR-G1 without circuit changes?

Yes-AP3105KTR-G1 is pin-to-pin compatible with AP3103KTR-G1 in SOT-23-6 and shares identical FB, SENSE, GATE, VCC, and GND connections. However, the CTRL pin must be left open or pulled to a defined voltage (not floating) to avoid unintended latch activation, unlike AP3103 which ignores this pin.

What protection features prevent transformer secondary failures?

AP3105KTR-G1 includes FOCP (Fast Over-Current Protection) with a 1.8 V threshold and ~100 ns response time, specifically designed to detect secondary winding shorts before catastrophic failure. Combined with 32 ms OLP delay and hiccup-mode recovery, it limits energy delivery during sustained overloads per IEC 62368-1 requirements.