STMicroelectronics STPS2L40U

Overview

STPS2L40U from STMicroelectronics is a 40 V, 2 A low-drop Schottky rectifier in SMB package, designed for high-frequency DC/DC converters and AC/DC adapters. It delivers typ. 0.31 V forward voltage at 2 A and 125 °C, supports 75 A non-repetitive surge current, and features avalanche rating for robustness in telecom and TV power supplies.

For engineers reviewing the STPS2L40U datasheet, STPS2L40U pinout, STPS2L40U application, or STPS2L40U equivalent, this device is selected for low-conduction-loss rectification in compact, thermally constrained 24–48 V input power stages where fast recovery and minimal reverse leakage are critical.

Technical Context

This Schottky rectifier uses a single-chip planar structure with metal–semiconductor junction optimized for low VF and negligible switching losses. Its 150 °C max junction temperature and 20 °C/W junction-to-lead thermal resistance (SMB) enable operation without heatsinks in board-level DC/DC converters up to 2 A average current.

The device exhibits 220 µA reverse leakage at 40 V and 25 °C, rising to 38 mA at 125 °C - a trade-off accepted for ultra-low forward drop. Avalanche-rated capability (158 W peak, 10 µs pulse) provides transient overvoltage tolerance beyond standard rectifier specifications.

Key Specifications

Pinout & Package

SMB surface-mount package (JEDEC DO-214AA), 3.3–3.95 mm wide × 5.1–5.6 mm long × 1.9–2.45 mm height, lead-free, UL94 V0 epoxy. Cathode marked by band on body.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SS24 and SB240, STPS2L40U delivers superior thermal performance and lower conduction loss at elevated temperatures, making it the preferred choice for space-constrained, high-efficiency 2 A power rails where junction temperature exceeds 100 °C.

Availability

STPS2L40U is available at Aetrix Electronics and suitable for telecom power supply, set-top box power supply, and TV power supply requiring stable component supply with full traceability and lifecycle support.

Supply support for STPS2L40U 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 industrial, automotive, and consumer markets.

STPS2L40U belongs to ST's high-efficiency Schottky rectifier product line, engineered specifically for high-frequency, low-voltage DC/DC conversion in compact power supplies where thermal and electrical efficiency are primary constraints.

FAQ

What is the maximum allowable PCB copper area for STPS2L40U in SMB package to achieve 2 A continuous current at 70 °C ambient?

With 2 cm² of 35 µm copper per lead on FR4, STPS2L40U achieves R_th(j-a) ≈ 50 °C/W, allowing 2 A continuous current at 70 °C ambient while maintaining T_j ≤ 150 °C. This is verified in Figure 13 of DS2146 Rev 6 and matches the SMB thermal derating curve in Figure 2.

Does STPS2L40U require a heatsink for 2 A operation in free-air conditions?

No heatsink is required. At 2 A and 25 °C ambient, junction temperature remains below 95 °C using only the PCB copper pads specified in Figure 17 (DS2146 Rev 6). The 20 °C/W R_th(j-l) enables sufficient heat transfer through leads into the board.

How does STPS2L40U's avalanche rating compare to standard Schottky rectifiers?

STPS2L40U is explicitly rated for 158 W peak avalanche power (10 µs, T_j = 125 °C), whereas most Schottky rectifiers lack formal avalanche testing or rating. This allows safe operation during voltage overshoots in flyback and LLC converters without external clamping.

Can STPS2L40U be used as a polarity protection diode in 24 V battery-powered equipment?

Yes - its 40 V V_RRM provides 16 V margin above 24 V nominal, and its 0.31 V VF adds minimal dropout. Reverse leakage remains <38 mA at 125 °C, ensuring low standby drain. The cathode band marking ensures correct orientation during manual assembly.