STMicroelectronics STPS40M120CTN

Overview

STPS40M120CTN from STMicroelectronics is a dual common-cathode 120 V, 40 A (total device) Schottky rectifier in TO-220AB package, featuring 0.61 V typical forward voltage at 125 °C and 220 A non-repetitive surge current, optimized for high-frequency SMPS in notebook adapters and LED lighting.

For engineers reviewing the STPS40M120CTN datasheet, STPS40M120CTN pinout, STPS40M120CTN application, or STPS40M120CTN equivalent, key selection criteria include low conduction loss (VF ≤ 0.67 V @ 125 °C/20 A), avalanche rating (1600 W peak), thermal resistance (Rth(j-c) = 0.80 °C/W total), and ECOPACK®2 compliance for industrial power conversion designs.

Technical Context

This dual-diode Schottky rectifier integrates two independent 20 A diodes sharing a common cathode terminal, enabling synchronous rectification or parallel operation in center-tapped topologies. Its low VF–IR trade-off targets medium-power, high-density AC/DC adapters where efficiency must be maintained across light-to-full load conditions.

The device operates up to 150 °C junction temperature with Rth(j-c) of 1.10 °C/W per diode and 0.80 °C/W total, supporting thermally constrained PCB layouts. Avalanche energy rating (1600 W at 10 µs) provides robustness against inductive switching transients in DC/DC converters.

Key Specifications

Pinout & Package

Packaged in TO-220AB with isolated tab (electrically connected to cathode), this dual-diode configuration uses three terminals: Pin 1 (Anode 1), Pin 2 (Cathode, common), Pin 3 (Anode 2). Mounting torque: 0.55 N·m (max 0.70 N·m).

Key Features

Applications

Equivalent & Alternatives

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

Compared with VS-40CPH12 and MBR40120CT, STPS40M120CTN delivers the lowest VF at high temperature and verified avalanche capability-critical for compact, high-reliability power supplies operating near thermal limits.

Availability

STPS40M120CTN is available at Aetrix Electronics and suitable for notebook adapters, LED drivers, gaming console PSUs, and industrial DC/DC converters requiring stable component supply and long-term manufacturability.

Supply support for STPS40M120CTN 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, designing and manufacturing analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The STPS series targets high-efficiency, high-reliability power conversion-specifically engineered for space-constrained, thermally demanding AC/DC and DC/DC applications where Schottky performance and ruggedness are critical.

FAQ

Is STPS40M120CTN pin-compatible with STPS40M120C?

Yes-STPS40M120CTN and STPS40M120C share identical TO-220AB package dimensions, pinout (A-K-A), and electrical specifications. The "N" suffix denotes tape-and-reel packaging per ST's updated ordering convention; functionally and mechanically interchangeable.

What is the maximum recommended heatsink temperature for continuous 40 A operation?

At 40 A total device current (20 A per diode), junction temperature must stay ≤150 °C. With Rth(j-c) = 0.80 °C/W and 2.4 W conduction loss per diode (per P = 0.54×IF(AV) + 0.0065×IF² RMS), max case temperature is 150 − (2.4 × 2 × 0.80) = 146.1 °C-so heatsink must maintain TC ≤ 146 °C.

Does STPS40M120CTN require a thermal pad or insulator when mounted to a grounded heatsink?

Yes-the metal tab is electrically connected to the common cathode (Pin 2). Direct mounting to a grounded heatsink creates a short unless an insulating washer (e.g., mica or silicone pad) and shoulder washer are used. ST recommends isolating the tab per AN5088 thermal mounting guidelines.

Can STPS40M120CTN replace a single 40 A discrete Schottky in a center-tapped transformer design?

No-it contains two 20 A diodes with shared cathode, not one 40 A diode. It replaces two separate 20 A Schottkys in center-tapped configurations. Using it as a single-diode substitute would halve current capability and misroute the cathode connection.