STMicroelectronics STPS2L40AF

Overview

STPS2L40AF from STMicroelectronics is a 40 V, 2 A low-drop Schottky rectifier in SMA Flat Notch surface-mount package, optimized for high-frequency DC/DC converters and low-voltage free-wheeling applications with VF(typ.) = 0.31 V at 2 A and 125 °C, Tj(max.) = 150 °C, and avalanche-rated (PARM = 158 W at tp = 10 µs). It serves as the output rectifier in telecom and TV power supplies where conduction loss minimization is critical.

For engineers reviewing the STPS2L40AF datasheet, STPS2L40AF pinout, STPS2L40AF application, or STPS2L40AF equivalent, key selection criteria include forward voltage drop at rated current and temperature, thermal resistance junction-to-lead (Rth(j-l) = 20 °C/W), avalanche capability, and SMB/SMA Flat Notch footprint compatibility in space-constrained board layouts.

Technical Context

This Schottky rectifier uses a single-chip planar structure with metal–semiconductor junction to eliminate minority-carrier storage delay, enabling negligible switching losses and operation up to several MHz. Its low VF stems from optimized barrier height and epitaxial layer doping, delivering conduction loss P ≈ 0.22 × IF(AV) + 0.06 × IF²(RMS) under square-wave conditions.

The device is avalanche-rated per IEC 61000-4-5 surge immunity requirements, with repetitive peak avalanche power of 158 W at 10 µs pulse width and Tj = 125 °C. Thermal management relies on conduction cooling via leads, supported by Rth(j-l) = 20 °C/W and Rth(j-a) = 200 °C/W (SMA Flat Notch, no copper pad).

Key Specifications

Pinout & Package

STPS2L40AF is housed in an SMA Flat Notch surface-mount package with cathode indicated by a band. The package features two gull-wing leads for mechanical stability and thermal conduction; lead pitch is 2.54 mm, body dimensions are 2.25–2.90 mm × 5.00–5.35 mm × 0.90–1.10 mm (L × W × H), and thermal resistance junction-to-ambient is 200 °C/W on standard FR4 with minimal copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SB240 and VSKY240, STPS2L40AF delivers the lowest VF at elevated temperature and highest avalanche energy (158 W), making it optimal for thermally constrained, high-surge industrial and telecom power stages where efficiency and ruggedness are jointly critical.

Availability

STPS2L40AF is available at Aetrix Electronics and suitable for telecom power supply, TV power supply, and battery charger designs requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for STPS2L40AF 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.

STPS2L40AF belongs to ST's high-efficiency Schottky rectifier product line, engineered specifically for high-frequency, low-voltage DC/DC conversion in space- and thermal-constrained power supplies.

FAQ

What is the maximum allowable case temperature for continuous operation of STPS2L40AF?

The device supports continuous operation up to 140 °C case temperature when mounted on a PCB with ≥1 cm² copper per lead, based on Rth(j-l) = 20 °C/W and Tj(max.) = 150 °C. Derating is required above this point to maintain junction temperature within limit.

Does STPS2L40AF require a heatsink in typical 2 A applications?

No external heatsink is required: with 1 cm² of 35 µm copper per lead on FR4, Rth(j-a) drops to ~60 °C/W, limiting junction rise to ~40 °C at 2 A (0.62 W dissipation), well within safe margin at 25 °C ambient.

How does the SMA Flat Notch package improve thermal performance over standard SMA?

The notch design increases lead surface area and improves solder fillet formation, reducing Rth(j-l) to 20 °C/W (vs. 25–30 °C/W for standard SMA) and enhancing mechanical reliability during thermal cycling in power applications.

Can STPS2L40AF replace STPS2L40U in existing SMB-based designs?

No - STPS2L40AF uses SMA Flat Notch (5.52 mm × 3.12 mm), while STPS2L40U uses SMB (5.60 mm × 3.95 mm); footprints and thermal paths differ significantly. Direct replacement requires PCB redesign and thermal validation.