STMicroelectronics STPS2L40AFN

Overview

STPS2L40AFN from STMicroelectronics is a 40 V, 2 A low-drop Schottky rectifier in SMA Flat Notch package, optimized for high-frequency DC/DC converters and adapter power supplies. It delivers typ. 0.31 V forward voltage at 2 A and 125 °C, features avalanche rating (158 W peak), and operates up to 150 °C junction temperature - enabling compact, efficient low-voltage polarity protection and freewheeling in telecom and consumer power stages.

For engineers reviewing the STPS2L40AFN datasheet, STPS2L40AFN pinout, STPS2L40AFN application, or STPS2L40AFN equivalent, key selection criteria include forward voltage at rated current, thermal resistance (R_th(j-l) = 20 °C/W), avalanche capability, SMB/SMA package footprint compatibility, and reverse leakage performance at 125 °C.

Technical Context

This Schottky rectifier uses a single-chip planar structure with metal–semiconductor junction optimized for minimal conduction loss and negligible switching loss. Its low VF (0.31 V typ. @ 2 A, 125 °C) and low IR (≤38 mA @ 40 V, 125 °C) directly reduce power dissipation in high-duty-cycle, high-frequency SMPS topologies.

The device is rated for repetitive peak reverse voltage of 40 V and average forward current of 2 A under defined thermal conditions (TL = 130 °C for SMA Flat Notch). Its R_th(j-l) = 20 °C/W enables effective lead-based heat transfer without heatsink, supporting surface-mount reliability in space-constrained board layouts.

Key Specifications

Pinout & Package

STPS2L40AFN is housed in an SMA Flat Notch surface-mount package (ECOPACK2-compliant, lead-free), featuring a cathode band marking and optimized thermal pad geometry for conduction cooling. The notch design enhances mechanical stability and orientation identification during automated placement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SS24 and MBR240, STPS2L40AFN provides lower forward voltage at elevated temperature, certified avalanche capability, and a notch-enhanced SMA Flat package that improves pick-and-place yield and thermal path consistency in high-volume consumer power assembly.

Availability

STPS2L40AFN is available at Aetrix Electronics and suitable for telecom power supply, set-top box power supply, and TV power supply requiring stable component supply across extended production lifecycles and seasonal demand spikes.

Supply support for STPS2L40AFN 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, MCU, and sensor solutions for automotive, industrial, and consumer markets.

STPS2L40AFN belongs to ST's high-efficiency Schottky rectifier product line, engineered specifically for space-constrained, high-frequency SMPS in consumer and telecom infrastructure where low VF, thermal resilience, and environmental compliance are critical.

FAQ

What is the maximum allowable ambient temperature for STPS2L40AFN at 2 A DC load?

At 2 A average forward current and δ = 0.5 duty cycle, STPS2L40AFN in SMA Flat Notch package supports up to 100 °C ambient temperature when mounted on FR4 with ≥1 cm² copper per lead (per Figure 4 in DS2146). Derating is required above this due to thermal resistance limits and junction temperature cap of 150 °C.

Does STPS2L40AFN require a heatsink for 2 A continuous operation?

No heatsink is required. With R_th(j-l) = 20 °C/W and typical PCB copper thermal paths, STPS2L40AFN achieves thermal equilibrium below 150 °C junction temperature at 2 A in standard 2-layer FR4 layouts. Heatsinking is unnecessary unless ambient exceeds 100 °C or copper area is severely restricted.

How does the SMA Flat Notch package improve manufacturability over standard SMA?

The notch provides visual and machine-vision alignment reference during SMT placement, reducing misalignment risk in high-speed pick-and-place. It also increases mechanical retention strength during reflow and board flex, improving long-term solder joint reliability in consumer-grade assemblies subject to thermal cycling.

Is STPS2L40AFN suitable for synchronous rectification replacement?

No - STPS2L40AFN is a passive Schottky rectifier, not a synchronous rectifier controller or MOSFET driver. It serves as a diode replacement in non-synchronous or hybrid topologies. For true synchronous rectification, discrete MOSFETs with gate drive timing control are required; this part cannot be substituted for those functions.