STMicroelectronics STPST3H100AF

Overview

STPST3H100AF from STMicroelectronics is a 3 A, 100 V Schottky trench rectifier in SOD128Flat package, optimized for high-frequency SMPS with low conduction and switching losses. It features 0.600 V typical forward voltage at 3 A/125 °C, 175 °C max junction temperature, avalanche rating of 5 A, and ECOPACK2 compliance. Used in telecom auxiliary supplies and LED lighting flyback converters.

For engineers reviewing the STPST3H100AF datasheet, STPST3H100AF pinout, STPST3H100AF application, or STPST3H100AF equivalent, key selection criteria include VF/IR trade-off at high Tj, thermal resistance (Rth(j-l) = 13 °C/W), avalanche ruggedness, flat-package board space savings, and compatibility with ST VIPer controllers in compact DC/DC designs.

Technical Context

This device employs ST's proprietary trench Schottky technology to achieve superior forward voltage versus reverse leakage balance-0.600 V VF at 3 A/125 °C and only 0.45 mA IR at 70 V/125 °C. Its low Qrr and soft recovery reduce EMI and switching losses in >100 kHz flyback and DC/DC topologies.

The SOD128Flat package enables high power density with 13 °C/W junction-to-lead thermal resistance and supports lead-free reflow. Designed for freewheeling, OR-ing, and reverse polarity protection, it pairs directly with ST's MOSFETs and VIPer ICs without external snubbers.

Key Specifications

Pinout & Package

SOD128Flat is a surface-mount, flat, dual-leaded package with cathode-marked side and exposed thermal pad. Dimensions: 4.7 mm × 2.4 mm × 1.0 mm (L × W × H), 26.4 mg weight, tape-and-reel packaging (3000 pcs/reel).

Key Features

Applications

Equivalent & Alternatives

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

Compared with STPST3H100UF and Vishay VSKY3100, STPST3H100AF uniquely balances ultra-compact SOD128Flat size, 175 °C operation, and certified avalanche ruggedness-making it optimal for space- and reliability-constrained auxiliary rails where thermal headroom and fault robustness are co-prioritized.

Availability

STPST3H100AF is available at Aetrix Electronics and suitable for telecom auxiliary power supplies, LED lighting flyback converters, and smart metering reverse polarity protection requiring stable component supply across multi-year production cycles.

Supply support for STPST3H100AF 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, designing and manufacturing microcontrollers, power devices, sensors, and analog ICs for industrial, automotive, and consumer markets.

STPST3H100AF belongs to ST's trench Schottky rectifier product line, engineered specifically for high-efficiency, high-density switched-mode power conversion in space-constrained and thermally demanding applications.

FAQ

What is the maximum allowable PCB copper area for optimal thermal performance of STPST3H100AF?

For SOD128Flat, ST recommends ≥100 cm² total copper area across both leads (50 cm² per lead) on 70 µm FR4 board to achieve Rth(j-a) ≈ 45 °C/W. Larger copper improves derating margin but does not reduce Rth(j-l), which remains fixed at 13 °C/W due to internal package construction.

Does STPST3H100AF require a heatsink in standard 3 A operation?

No heatsink is required. At 3 A average current and 130 °C lead temperature, junction temperature stays ≤155 °C with ≥50 cm² copper per lead. The 13 °C/W Rth(j-l) enables full-rated current via PCB copper alone-verified in ST AN5088 thermal mounting guidelines.

How does the avalanche rating of 5 A translate to real-world circuit protection?

The 5 A IAS rating corresponds to survivability under unclamped inductive switching with L = 300 µH and VDD = 15 V. It guarantees single-pulse energy absorption up to EAS = 3.75 mJ, protecting against transformer leakage inductance spikes in flyback converters without snubber networks.

Can STPST3H100AF replace standard silicon diodes in existing 100 V SMPS designs?

Yes-with design review. Its 0.600 V VF reduces conduction loss by ~40% vs 1.1 V Si diodes, but layout must minimize parasitic inductance to avoid voltage overshoot during fast recovery. Also verify that existing thermal pads match SOD128Flat footprint (4.7 × 2.4 mm) and that peak reverse voltage remains ≤100 V.