Diodes Incorporated AL17050WT-7

Overview

AL17050WT-7 from Diodes Incorporated is a universal AC-input high-voltage step-down regulator IC integrating a 500V MOSFET, delivering constant voltage (CV) regulation without opto-coupler feedback. It operates across 85–265 VAC input, supports ≤60 mA output current at 3.3/5 V, and achieves high efficiency in Discontinuous Conduction Mode (DCM) for low-power offline applications such as smart home appliance power supplies and IoT sensor node standby converters.

For engineers reviewing the AL17050WT-7 datasheet, AL17050WT-7 pinout, AL17050WT-7 application, or AL17050WT-7 equivalent, this device is selected for cost-sensitive, isolated-free AC/DC conversion where BOM reduction, thermal safety, and light-load efficiency are critical design constraints.

Technical Context

The AL17050WT-7 implements primary-side CV control using internal peak-current sensing and adaptive frequency modulation-switching frequency drops under light load to maintain ≥75% efficiency at 10% load. Its error amplifier compensation dynamically adjusts reference voltage based on load transients, enabling ±3% output regulation over line and load variations without secondary-side feedback.

Protection logic integrates five independent functions: open-loop detection (60 mV FB threshold), short-circuit protection (450 mA peak current limit), over-temperature shutdown (+150°C with +30°C hysteresis), VCC UVLO (3.4 V stop / 2.4 V restart), and over-load protection triggered after 170 ms at FB ≤1.7 V-ensuring robust operation in unattended embedded systems.

Key Specifications

Pinout & Package

SOT25 package: 5-pin surface-mount, thermally enhanced with exposed drain pad connected internally to Pin 5. Pin 3 and Pin 4 are internally bonded to common source node.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar universal-input offline buck regulator applications.

Compared with MP174G-5-Z and LNK3206D, the AL17050WT-7 uniquely combines universal AC input, integrated 500 V MOSFET, and primary-side CV control in SOT25-offering lowest component count and smallest footprint for non-isolated 3.3/5 V offline supplies under 60 mA.

Availability

AL17050WT-7 is available at Aetrix Electronics and suitable for smart home appliance power supplies, IoT sensor node standby converters, and industrial control panel auxiliary supplies requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for AL17050WT-7 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 company specializing in discrete, analog, and mixed-signal solutions for power management, signal integrity, and connectivity applications.

The AL17050WT-7 belongs to Diodes' universal offline regulator product line, designed specifically for cost-sensitive, non-isolated AC/DC conversion in consumer and industrial edge devices where BOM reduction and thermal resilience are prioritized.

FAQ

What is the maximum continuous output current supported by AL17050WT-7?

The AL17050WT-7 supports up to 60 mA continuous output current at 3.3 V or 5 V, constrained by its 220 mA peak current limit and DCM operation mode. This rating assumes proper thermal design with SOT25 mounted on ≥1 cm² copper pour and ambient temperature ≤+105°C per datasheet recommendations.

Does AL17050WT-7 require an external opto-coupler for regulation?

No. The AL17050WT-7 uses primary-side constant voltage (CV) control with internal feedback sampling via the FB pin, eliminating the need for an opto-coupler or secondary-side TL431 reference. Output voltage is set by an external resistor divider (R1/R2) connected to FB and SOURCE pins.

How does the AL17050WT-7 handle startup under low-input-voltage conditions?

During startup, the AL17050WT-7 employs a three-stage soft-start sequence: minimum off-time ramps from 56 µs → 28 µs → 14 µs over 384 total switching cycles. This prevents output overshoot and ensures reliable regulation even when input DC bus drops to 70 V, as required for universal AC operation.

Can AL17050WT-7 be used in full-wave rectified input configurations?

Yes. While optimized for half-wave rectification with 3 µF/W input capacitance, the AL17050WT-7 supports full-wave rectified inputs-requiring reduced input capacitance (e.g., 1.5 µF/W) to maintain minimum DC bus voltage above 70 V and avoid thermal shutdown during low-line operation.