STMicroelectronics STPS3170AFN

Overview

STPS3170AFN from STMicroelectronics is a 170 V, 3 A Schottky rectifier in SMA Flat Notch package, designed for high-frequency switching applications including SMPS and DC/DC converters. It features low forward voltage (0.63 V typ. at 125 °C, 3 A), negligible switching losses, avalanche rating, and operates up to 175 °C junction temperature - enabling compact, efficient power conversion in space-constrained LED lighting and telecom power supplies.

For engineers reviewing the STPS3170AFN datasheet, STPS3170AFN pinout, STPS3170AFN application, or STPS3170AFN equivalent, key selection criteria include its 170 V reverse voltage rating, thermal resistance of 20 °C/W (junction-to-lead), low leakage current (<4.0 µA at 25 °C), ECOPACK2 compliance, and suitability for freewheeling and polarity protection circuits where conduction loss minimization is critical.

Technical Context

This Schottky diode leverages platinum-silicide barrier technology to achieve ultra-low forward voltage and near-zero reverse recovery charge - eliminating switching losses typical of PN junction rectifiers. Its avalanche-rated structure supports robust transient handling in unclamped inductive switching events.

The device is optimized for continuous conduction mode (CCM) and discontinuous conduction mode (DCM) topologies, with thermal performance validated across SMA Flat Notch mounting configurations. Junction-to-lead thermal resistance (20 °C/W) enables direct PCB copper pad heat sinking without external heatsinks in moderate-power designs.

Key Specifications

Pinout & Package

STPS3170AFN is housed in an SMA Flat Notch surface-mount package with cathode indicated by a band. The package uses lead-free epoxy compliant with UL94 V0 and ECOPACK2 environmental standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SB3170 and VSSAF317-M3/84A, STPS3170AFN delivers the lowest forward voltage, explicit avalanche rating, and ECOPACK2 environmental certification - making it optimal for industrial telecom and LED lighting where efficiency, reliability, and regulatory compliance are jointly prioritized.

Availability

STPS3170AFN is available at Aetrix Electronics and suitable for LED lighting drivers, telecom DC/DC converters, and industrial SMPS requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for STPS3170AFN 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 discrete devices, analog ICs, and MEMS sensors for industrial, automotive, and consumer markets.

STPS3170AFN belongs to ST's high-efficiency Schottky rectifier product line, engineered specifically for high-frequency, low-loss power conversion in space- and thermal-constrained applications such as LED drivers and telecom power supplies.

FAQ

What is the maximum allowable PCB copper area for thermal optimization of STPS3170AFN?

The SMA Flat Notch package achieves optimal thermal performance with ≥100 mm² of 35 µm copper per lead, as verified in Figure 10 of DS10645. Using 200 mm² reduces R_th(j-a) to ~3.0 °C/W on FR4, enabling 3 A operation at 70 °C ambient without airflow. Smaller pads increase thermal resistance linearly - 50 mm² raises R_th(j-a) to ~4.5 °C/W.

Does STPS3170AFN require a heatsink in standard 2-layer PCB layouts?

No heatsink is required. With 100 mm² copper per lead on a 2-layer FR4 board, STPS3170AFN maintains T_j < 125 °C at 3 A and 50 °C ambient. Its 20 °C/W R_th(j-l) allows direct conduction cooling through soldered leads into internal copper planes - confirmed by thermal imaging in AN5088.

How does the avalanche rating of STPS3170AFN improve system reliability in flyback converters?

The 210 W avalanche energy rating (t_p = 10 µs, T_j = 125 °C) enables safe absorption of unclamped inductive energy during MOSFET turn-off transients. This prevents secondary-side voltage spikes >200 V that would otherwise degrade output capacitors or damage synchronous rectifier controllers in flyback designs.

Can STPS3170AFN replace STPS3170UF in SMB Flat footprint designs?

No - STPS3170AFN uses SMA Flat Notch (5.52 × 3.12 mm) while STPS3170UF uses SMB Flat (5.6 × 3.95 mm). Pad dimensions differ significantly: SMA Notch requires 1.20 mm lead spacing vs. SMB's 1.52 mm. Mechanical interference and solder joint reliability would be compromised without PCB redesign.