Diodes Incorporated AP3768MTR-G1

Overview

AP3768MTR-G1 from Diodes Incorporated is a primary-side regulation (PSR) AC/DC controller for offline flyback converters in battery chargers and adapters. It delivers optocoupler-free constant voltage/constant current (CV/CC) regulation using PFM in DCM, achieves ≤30 mW no-load input power, integrates programmable cable drop compensation, and operates with 12–30 V_VCC, −40°C to +85°C ambient.

For engineers reviewing the AP3768MTR-G1 datasheet, AP3768MTR-G1 pinout, AP3768MTR-G1 application, or AP3768MTR-G1 equivalent, key selection criteria include its PSR-based CV/CC accuracy, built-in cable compensation tuning, 490–535 mV current sense threshold, 3.97–4.09 V feedback reference, and SO-8 thermal resistance of 190°C/W.

Technical Context

The AP3768MTR-G1 implements proprietary PFM control with leading-edge blanking and t_ONS-based timing to maintain stable DCM operation across line/load variations. Its internal bias regulator sets V_BIAS at 1.0–1.2 V and enables start-up at 17–21 V while sustaining operation down to 8.2–10.2 V.

It embeds dual-loop CV/CC regulation: FB pin monitors auxiliary winding voltage for CV, CS pin senses primary current for CC, and CPR/CPC pins configure cable compensation via external R-C network. Overvoltage protection triggers at 7–9 V on FB, and short-circuit protection is integrated without external components.

Key Specifications

Pinout & Package

AP3768MTR-G1 is housed in an SO-8 surface-mount package (6.20 × 4.00 × 1.75 mm), RoHS-compliant and halogen-free per Diodes Inc. "Green" definition (Br+Cl <1500 ppm, Sb <1000 ppm).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar primary-side regulation controller applications.

Compared with MP6004DJ-LF-Z and LNK3206P, AP3768MTR-G1 uniquely combines optocoupler-free CV/CC, tunable cable compensation, and vertical CC profiling-enabling high-accuracy, cable-aware charging in compact 5–15 W adapters without secondary sensing.

Availability

AP3768MTR-G1 is available at Aetrix Electronics and suitable for smartphone wall adapters, USB-C auxiliary supplies, LED lighting drivers, and industrial IoT sensor power requiring stable component supply and long-lifecycle support.

Supply support for AP3768MTR-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 ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.

The AP3768 belongs to Diodes' AC/DC PSR controller product line, engineered specifically for cost-sensitive, high-efficiency, low-noise offline chargers and adapters targeting consumer and industrial markets.

FAQ

What external components are required for basic AP3768MTR-G1 operation?

The minimum external components are: a current-sense resistor on CS, a VCC startup resistor and bulk capacitor, an NPN transistor driven by OUT, a flyback transformer with auxiliary winding, and feedback resistors from auxiliary winding to FB. CPR and CPC require optional R-C network only if cable compensation is needed.

How does the AP3768MTR-G1 achieve constant current without secondary sensing?

It uses primary-side current sensing via the CS pin and correlates primary peak current to output current through transformer turns ratio and DCM timing. The proprietary CC tightening algorithm corrects for variation in transformer leakage inductance and diode forward voltage to maintain tight current regulation.

Can the AP3768MTR-G1 support multiple output voltages?

No-it is designed for single-output flyback topologies with CV/CC regulation derived from one auxiliary winding. Multi-output designs require additional post-regulation or separate controllers, as the FB pin only references one winding and lacks cross-regulation capability.

Is the SO-8 package thermally adequate for 10 W continuous operation?

Yes-under natural convection with a 2-layer 1 oz copper PCB and 2 cm² exposed copper pour under the SO-8 footprint, junction temperature rise remains within 150°C limit at 10 W output. Thermal simulation or IR imaging is recommended for final layout validation.