STMicroelectronics STPS20SM120SFP

Overview

STPS20SM120SFP from STMicroelectronics is a 120 V, 20 A average forward current Schottky rectifier in insulated TO-220FPAB package, featuring 0.65 V typical forward voltage at 125 °C and 20 A, avalanche-rated (900 W peak), and optimized for high-frequency SMPS in notebook adapters and LED lighting.

For engineers reviewing the STPS20SM120SFP datasheet, STPS20SM120SFP pinout, STPS20SM120SFP application, or STPS20SM120SFP equivalent, key selection criteria include reverse voltage rating (120 V), thermal resistance (4 °C/W junction-to-case), insulation rating (2000 VRMS), low VF conduction loss, and avalanche ruggedness for transient robustness in DC/DC converters.

Technical Context

This Schottky diode operates as a unidirectional power rectifier with zero minority-carrier storage, enabling high-frequency switching (>100 kHz) without reverse recovery losses. Its metal–semiconductor junction delivers fast turn-on and negligible Qrr, critical for efficiency in synchronous and quasi-resonant topologies.

The TO-220FPAB package provides electrical isolation between the heatsink-mounting surface and internal die, rated for 2000 VRMS sine-wave withstand, making it suitable for isolated secondary-side rectification where creepage/clearance and safety certification are mandatory.

Key Specifications

Pinout & Package

TO-220FPAB is an insulated variant of TO-220 with electrically isolated mounting tab (2000 VRMS rating). The device has 3 terminals: Anode (pin 1), Cathode (pin 2), and Isolated Mounting Tab (electrically connected to cathode internally but physically insulated from heatsink).

Key Features

Applications

Equivalent & Alternatives

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

Compared with VS-20CPH12 and MBR20120CT, STPS20SM120SFP uniquely combines certified 2000 VRMS insulation, avalanche energy rating, and low-VF Schottky performance in a standard TO-220 footprint-enabling compact, safety-compliant, and transient-robust adapter designs without trade-offs.

Availability

STPS20SM120SFP is available at Aetrix Electronics and suitable for notebook adapters, LED drivers, and industrial DC/DC modules requiring stable component supply, safety-certified isolation, and high-reliability power conversion.

Supply support for STPS20SM120SFP 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 analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The STPS series targets high-efficiency, high-reliability power rectification in compact AC-DC and DC-DC converters-specifically engineered for efficiency-critical, thermally constrained, and safety-certified applications like portable computing power supplies.

FAQ

Is STPS20SM120SFP pin-compatible with standard TO-220AB diodes?

No. While both use three-terminal TO-220 outlines, STPS20SM120SFP uses the insulated TO-220FPAB variant where the mounting tab is electrically isolated from the cathode. Standard TO-220AB parts have the tab internally connected to the cathode, so direct substitution risks shorting the heatsink to circuit ground unless isolation is added externally.

What is the maximum recommended heatsink thermal resistance for 20 A continuous operation?

At 20 A average current and 125 °C junction temperature, with ambient at 70 °C, the allowable temperature rise is 55 °C. Given R_th(j-c) = 4 °C/W and typical R_th(c-s) ≈ 0.5 °C/W, the heatsink must provide ≤13.25 °C/W total thermal resistance (R_th(s-a)) to maintain safe operation without derating.

Does STPS20SM120SFP require a snubber circuit in flyback or LLC converters?

No snubber is required for normal operation due to zero reverse recovery charge (Q_rr ≈ 0). However, a small RC snubber may still be used across the diode to damp high-frequency ringing caused by layout parasitics-not device behavior-especially in high dv/dt environments exceeding 50 V/ns.

Can STPS20SM120SFP be used in parallel configurations for higher current?

Yes, but only with matched forward voltage characteristics and symmetrical PCB layout. ST's datasheet confirms parallel operation is feasible; however, thermal coupling and current sharing must be validated via thermal imaging and load testing, as V_F negative temperature coefficient can cause imbalance if one device runs hotter than the other.