STMicroelectronics STPS140U

Overview

STPS140U from STMicroelectronics is a 40 V, 1 A surface-mount Schottky rectifier in SMB package, designed for low-voltage, high-frequency DC-DC converters and reverse polarity protection circuits. It features a typical forward voltage drop of 0.43 V at 125 °C and 1 A, avalanche rating up to 65 W (10 µs), and thermal resistance R_th(j-l) of 25 °C/W.

For engineers reviewing the STPS140U datasheet, STPS140U pinout, STPS140U application, or STPS140U equivalent, key selection criteria include forward voltage drop at elevated temperature, surge current capability (60 A), junction-to-lead thermal resistance, and ECOPACK2 compliance for RoHS-constrained industrial power designs.

Technical Context

This Schottky rectifier operates as a unidirectional, low-loss power switching diode with negligible reverse recovery charge-enabling high-efficiency operation in SMPS and battery charger topologies. Its avalanche-rated construction supports transient energy absorption without external snubbers.

The device uses a planar silicon Schottky barrier structure optimized for low V_F and stable leakage across -65 °C to +150 °C operating junction range. Thermal performance is defined by junction-to-lead (25 °C/W) and junction-to-ambient (80 °C/W on FR4 with 2 cm² copper per lead) metrics.

Key Specifications

Pinout & Package

STPS140U is housed in an SMB (DO-214AA) surface-mount package with cathode band marking. The two-terminal configuration supports simple PCB layout with minimal trace inductance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SS14 and MBR140, STPS140U delivers the lowest forward voltage at elevated temperature and certified avalanche ruggedness-making it optimal for thermally constrained, high-reliability 40 V-class SMPS where efficiency and transient immunity are jointly critical.

Availability

STPS140U is available at Aetrix Electronics and suitable for TV power supplies, set-top box auxiliary rails, and battery charger OR-ing circuits requiring stable component supply and long-term industrial availability.

Supply support for STPS140U 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 microcontrollers, power devices, sensors, and analog ICs for automotive, industrial, and consumer markets.

The STPS series targets high-efficiency, surface-mount power rectification-specifically engineered for cost-sensitive, space-constrained AC-DC and DC-DC converters operating below 45 V.

FAQ

What is the maximum allowable PCB copper area for optimal thermal performance of STPS140U?

For best thermal performance, ST recommends ≥2 cm² of 35 µm-thick copper per lead on FR4 board, achieving R_th(j-a) ≈ 80 °C/W. Larger copper areas further reduce thermal resistance, but diminishing returns occur beyond 5 cm². No minimum copper area is specified, though <0.5 cm² raises risk of exceeding T_j(max) at full I_F(AV).

Does STPS140U require a heatsink in standard SMB mounting?

No external heatsink is required. The SMB package relies on PCB copper as the primary heatsink. With ≥2 cm² copper per lead on FR4, junction temperature remains within spec at 1 A DC and 45 °C ambient. Forced air or metal-core boards may allow higher current, but are not necessary for rated operation.

How does the avalanche rating of STPS140U improve system reliability?

The 65 W avalanche power rating (10 µs pulse at 125 °C) allows STPS140U to absorb inductive energy during switch turn-off without failure-critical in flyback and boost converters. This eliminates need for snubber networks, reduces component count, and prevents single-point failure modes caused by voltage overshoot.

Can STPS140U replace a standard PN-junction rectifier in an existing design?

Yes, with verification of reverse voltage margin and thermal layout. STPS140U offers lower V_F, zero reverse recovery, and higher I_FSM than equivalents like 1N5819. However, its higher reverse leakage at temperature may affect ultra-low-power standby circuits-confirm IR < 10 µA at worst-case ambient if used in always-on applications.