STMicroelectronics STPS20SM120STN

Overview

STPS20SM120STN from STMicroelectronics is a 120 V, 20 A average forward current Schottky rectifier in TO-220AB package, featuring 0.65 V typical forward voltage at 125 °C and 20 A, avalanche-rated operation up to 900 W (10 µs), and 2000 VRMS insulation (TO-220FPAB variant). It is engineered for high-frequency switching in notebook adapters, DC/DC converters, and LED lighting power stages.

For engineers reviewing the STPS20SM120STN datasheet, STPS20SM120STN pinout, STPS20SM120STN application, or STPS20SM120STN equivalent, key selection criteria include forward voltage drop at full load, thermal resistance (Rth(j-c) = 1.55 °C/W), avalanche energy capability, and insulated vs. non-insulated package variants for safety-critical AC-DC front-end designs.

Technical Context

This device operates as a unidirectional power rectifier with zero recovery time and no minority-carrier storage, enabling efficient high-frequency (>100 kHz) operation in SMPS topologies. Its Schottky barrier construction delivers low conduction loss while maintaining robust reverse blocking up to 120 V repetitive peak voltage.

Thermal design is critical: junction-to-case resistance is 1.55 °C/W in TO-220AB, requiring mechanical mounting to heatsinks with 0.55 N·m torque. Avalanche rating supports transient overvoltage resilience during inductive switching events without secondary protection components.

Key Specifications

Pinout & Package

STPS20SM120STN is housed in TO-220AB package: 3-terminal through-hole outline with isolated metal tab (anode-connected case), epoxy meeting UL 94 V0, and mechanical dimensions per ST DS8944 Rev 4 (A = 4.5 mm, D = 15.5 mm, L = 13.5 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with VS-20CPH12 and MBR20120CT, STPS20SM120STN offers superior thermal performance (1.55 °C/W), lower conduction loss (0.65 V), and certified avalanche ruggedness-making it optimal for space-constrained, high-efficiency, and transient-resilient AC-DC and DC/DC power stages.

Availability

STPS20SM120STN is available at Aetrix Electronics and suitable for notebook adapters, LED drivers, and industrial DC/DC converters requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for STPS20SM120STN 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, power, microcontroller, and sensor solutions for automotive, industrial, and consumer markets.

STPS20SM120STN belongs to ST's high-current Schottky rectifier product line, developed specifically for high-efficiency, high-reliability AC-DC and isolated DC/DC power conversion in portable and industrial equipment.

FAQ

Is STPS20SM120STN pin-compatible with TO-220FPAB variants like STPS20SM120SFP?

No. STPS20SM120STN uses TO-220AB (non-insulated tab), while STPS20SM120SFP uses TO-220FPAB with 2000 VRMS insulation. The pinout is identical (anode-tab/cathode-lead), but mechanical mounting differs: TO-220AB requires insulating hardware on grounded heatsinks; TO-220FPAB does not. Electrical substitution is possible only if insulation requirements match.

What is the maximum recommended PCB copper area for thermal relief at 20 A continuous?

For TO-220AB mounting with 0.55 N·m torque, ST recommends ≥400 mm² of 2-oz copper on the anode pad, connected via ≥4 thermal vias (0.3 mm diameter) to internal ground planes. This achieves <25 °C rise above ambient at 20 A, assuming still-air conditions and proper heatsink contact.

Does STPS20SM120STN require derating at elevated ambient temperatures?

Yes. Per Figure 2 in DS8944, IF(AV) drops linearly from 20 A at 25 °C ambient to ~12 A at 70 °C ambient (δ = 0.5, TO-220AB). Derating is governed by Rth(j-a) ≈ Rth(j-c) + Rth(c-a); for forced-air cooling, Rth(c-a) can be reduced to ≤1.2 °C/W, restoring full 20 A capability up to 60 °C ambient.

Can STPS20SM120STN replace a standard PN-junction rectifier like 1N5408 in a 12 V/5 A power supply?

Yes, with significant benefit: VF drops from ~0.95 V (1N5408) to 0.65 V (STPS20SM120STN), reducing conduction loss by ~32% and junction temperature rise by ~22 °C at 5 A. However, note VRRM is higher (120 V vs. 1000 V), so verify reverse voltage stress remains within 120 V in the target circuit.