STMicroelectronics STPS20SM120SR

Overview

STPS20SM120SR from STMicroelectronics is a 120 V, 20 A average forward current Schottky rectifier in TO-220FPAB insulated package, featuring 0.65 V typical forward voltage at 20 A/125 °C, 2000 VRMS insulation rating, and avalanche-rated operation for robustness in high-frequency SMPS. It serves as the primary output rectifier in notebook adapters and DC/DC converters where low conduction loss and thermal reliability are critical.

For engineers reviewing the STPS20SM120SR datasheet, STPS20SM120SR pinout, STPS20SM120SR application, or STPS20SM120SR equivalent, key selection criteria include forward voltage drop at full load, junction-to-case thermal resistance, insulation voltage rating, avalanche energy capability, and TO-220FPAB mounting torque compliance.

Technical Context

This device operates as a unidirectional power rectifier with zero recovery charge and no minority-carrier storage, enabling efficient high-frequency switching up to several hundred kHz. Its Schottky barrier structure delivers low VF and fast turn-off, eliminating reverse recovery losses common in PN diodes.

The TO-220FPAB package integrates an electrically insulated metal tab rated for 2000 VRMS, allowing direct heatsink mounting without isolation hardware. Thermal performance is defined by Rth(j-c) = 4 °C/W, supporting sustained 20 A operation with appropriate heatsinking.

Key Specifications

Pinout & Package

STPS20SM120SR uses the TO-220FPAB package: insulated metal tab (2000 VRMS), 3-terminal configuration, UL 94 V0 epoxy, recommended mounting torque 0.55 N·m. The case serves as the cathode terminal.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Schottky rectifier applications.

Compared with VS-20CPH12 and MUR20120CT, STPS20SM120SR uniquely combines insulation, low VF, and avalanche rating in a single TO-220FPAB device-enabling simplified, safer, and more efficient designs in space-constrained consumer power supplies.

Availability

STPS20SM120SR is available at Aetrix Electronics and suitable for notebook AC adapters, LED lighting drivers, and desktop PC power supplies requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for STPS20SM120SR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power devices, sensors, and analog ICs for automotive, industrial, and consumer markets.

STPS20SM120SR belongs to ST's high-efficiency Schottky rectifier product line, engineered specifically for high-frequency, high-reliability AC-DC and DC-DC conversion in compact, thermally constrained consumer power systems.

FAQ

What is the maximum allowable case temperature for continuous operation?

The maximum operating junction temperature is +150 °C. With Rth(j-c) = 4 °C/W and 20 A forward current, the case temperature must remain ≤100 °C under worst-case ambient and airflow conditions to maintain margin. Derating curves in DS8944 show IF(AV) drops to ~14 A at Tamb = 70 °C with natural convection on a 100 cm² heatsink.

Can STPS20SM120SR replace a standard TO-220AB diode in an existing design?

Yes, but only if the PCB layout accommodates the TO-220FPAB's insulated tab and revised mechanical dimensions (e.g., L3 = 28.6–30.6 mm vs. TO-220AB's L = 13–14 mm). Electrical substitution is valid, but mechanical fit and thermal interface must be revalidated due to different Rth(j-c) and mounting torque specs.

Is this diode suitable for synchronous rectification circuits?

No-it is a passive Schottky rectifier, not a synchronous rectifier controller or MOSFET driver. It replaces the secondary-side MOSFET in quasi-resonant flyback designs but cannot be actively gated. Its role is purely uncontrolled conduction; timing and control remain with the primary-side PWM IC.

Does the 2000 VRMS insulation rating apply to DC voltage stress?

Yes-the 2000 VRMS rating corresponds to ~2800 VDC peak insulation capability per IEC 60950-1. This allows safe use across reinforced insulation barriers in Class II adapters, even under transient overvoltage conditions up to 2500 VDC, provided creepage/clearance distances meet regulatory requirements.