STMicroelectronics STPS340S

Overview

STPS340S from STMicroelectronics is a 40 V, 3 A average forward current Schottky rectifier in SMC package, featuring 0.52 V typical forward voltage at 125 °C and 3 A, 150 °C maximum junction temperature, and avalanche-rated operation - deployed in telecom power supplies for high-frequency DC-DC conversion with low conduction loss.

For engineers reviewing the STPS340S datasheet, STPS340S pinout, STPS340S application, or STPS340S equivalent, key selection criteria include thermal resistance (R_th(j-a) ≈ 4.5 °C/W on 100 cm² copper), surge current capability (75 A non-repetitive), low VF stability over temperature, and surface-mount compatibility with SMC footprint per DS0792 Rev 13.

Technical Context

This Schottky rectifier uses a planar silicon epitaxial structure optimized for minimal reverse recovery charge (Q_rr ≈ 0 nC) and negligible switching losses - enabling operation up to several MHz in synchronous rectification and flyback topologies. Its low R_th(j-l) (20 °C/W) and R_th(j-c) (not specified for SMC but comparable to SMC-class devices) support direct PCB copper thermal spreading without heatsinks in medium-power applications.

The device operates under δ = 0.5 square-wave conditions with IF(AV) derated to 3 A at TL = 105 °C, and exhibits IR ≤ 10 mA at VR = 40 V and Tj = 125 °C - confirming suitability for low-leakage, high-efficiency secondary-side rectification where thermal runaway risk is mitigated by controlled (dP_tot/dT_j) < (1/R_th(j-a)) behavior.

Key Specifications

Pinout & Package

STPS340S is housed in SMC (DO-214AB) surface-mount package: cathode marked by band, dual-leaded, thermally enhanced plastic body with epoxy meeting UL94 V0. Dimensions: D = 5.55–6.25 mm, E = 7.75–8.15 mm, L = 0.75–1.50 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with VS-3EYH04-M3 and SB340-E3/57T, STPS340S delivers superior thermal performance (R_th(j-a) ≈ 4.5 °C/W), guaranteed avalanche ruggedness, and tighter VF consistency across temperature - making it optimal for high-reliability telecom and industrial DC-DC modules where transient immunity and efficiency margins are critical.

Availability

STPS340S is available at Aetrix Electronics and suitable for telecom power supply, set-top box power supply, and TV power supply requiring stable component supply and long-term industrial lifecycle support.

Supply support for STPS340S 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 industrial, automotive, and consumer markets.

STPS340S belongs to ST's high-efficiency Schottky rectifier product line, engineered specifically for high-frequency switch-mode power supplies where low VF, fast switching, and thermal resilience are mandatory design constraints.

FAQ

What is the maximum allowable PCB copper area for optimal thermal performance of STPS340S?

Per DS0792 Figure 15, R_th(j-a) drops to ≈4.5 °C/W with ≥100 cm² total copper surface under both leads on FR4 board (35 µm thickness). Using less than 50 cm² raises thermal resistance above 6.5 °C/W, limiting continuous current to ≤2.2 A at 70 °C ambient - verified via curve-fit data in datasheet page 5.

Does STPS340S support reflow soldering per JEDEC J-STD-020?

Yes - STPS340S in SMC package is qualified for lead-free reflow per JEDEC J-STD-020D, with peak temperature up to 260 °C (10 sec max). The epoxy meets UL94 V0 and passes MSL Level 1 rating, requiring no dry-pack or baking prior to assembly.

Can STPS340S replace a standard PN rectifier like 1N5822 in existing designs?

Yes - STPS340S shares identical SMC footprint and pinout with 1N5822, but delivers 0.52 V vs. 0.9 V typical VF at 3 A, reducing conduction loss by ~42%. No layout change is needed, though thermal relief pads should be verified for 150 °C junction operation.

Is STPS340S suitable for reverse polarity protection in 24 V automotive accessory circuits?

No - while rated for 40 V V_RRM, STPS340S lacks AEC-Q101 qualification and has no guaranteed operation beyond 125 °C junction temperature. Automotive reverse protection requires extended temperature range (−40 to 150 °C) and transient immunity per ISO 7637-2, which this part does not specify.