STMicroelectronics STPS20SM120ST

Overview

STPS20SM120ST from STMicroelectronics is a 120 V, 20 A average forward current Schottky rectifier in TO-220AB package, featuring 0.65 V typical forward voltage at 125 °C and 20 A, avalanche-rated (900 W peak), and optimized for high-frequency SMPS in notebook adapters. It delivers low conduction loss and thermal stability up to 150 °C junction temperature.

For engineers reviewing the STPS20SM120ST datasheet, STPS20SM120ST pinout, STPS20SM120ST application, or STPS20SM120ST equivalent, key selection criteria include forward voltage drop at full load, avalanche energy handling, thermal resistance (R_th(j-c) = 1.55 °C/W), insulation requirements, and TO-220AB mechanical mounting compatibility.

Technical Context

This Schottky diode operates as a unidirectional power rectifier with zero recovery charge and minimal switching loss-enabling efficient operation in DC/DC converters and AC/DC secondary-side rectification. Its low VF and high I_F(AV) support continuous conduction mode at high switching frequencies (>100 kHz).

The device integrates avalanche ruggedness (900 W at 10 µs) and thermal robustness (T_j(max) = 150 °C), with R_th(j-c) = 1.55 °C/W enabling direct heatsink mounting without isolation pads in non-isolated topologies. Insulated variants (e.g., TO-220FPAB) are separate order codes-not applicable to STPS20SM120ST.

Key Specifications

Pinout & Package

TO-220AB package: 3-terminal through-hole plastic case with electrically isolated tab (anode-connected), standard mounting hole, and 0.55 N·m recommended torque. Tab is electrically connected to anode.

Key Features

Applications

Equivalent & Alternatives

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

Compared with VS-20SQ120 and SB20120, STPS20SM120ST uniquely combines 20 A rating, 0.65 V V_F, avalanche protection, and anode-tab isolation-making it optimal for thermally constrained, high-reliability adapter and DC/DC applications where transient immunity and layout flexibility matter.

Availability

STPS20SM120ST is available at Aetrix Electronics and suitable for notebook adapters, DC/DC converters, and LED lighting systems requiring stable component supply, long-lifecycle availability, and consistent thermal performance across production batches.

Supply support for STPS20SM120ST 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.

STPS20SM120ST belongs to ST's high-efficiency Schottky rectifier product line, engineered specifically for high-frequency, high-current power conversion in space-constrained consumer power supplies.

FAQ

Is STPS20SM120ST pin-compatible with TO-220FPAB variants like STPS20SM120SFP?

No. STPS20SM120ST uses TO-220AB with anode-connected tab, while STPS20SM120SFP uses TO-220FPAB with electrically insulated tab rated for 2000 V_RMS. Mechanical footprint and thermal mounting differ-direct substitution requires PCB and heatsink redesign.

What is the maximum allowable case temperature for continuous 20 A operation?

At I_F(AV) = 20 A, junction temperature must not exceed +150 °C. With R_th(j-c) = 1.55 °C/W and P_D ≈ 13 W (using V_F = 0.65 V), case temperature must be held ≤120 °C to maintain 30 °C safety margin-achievable with ≥15 cm² aluminum heatsink.

Does STPS20SM120ST require a minimum heatsink area for safe operation at 15 A?

Yes. At 15 A and 0.65 V V_F, power dissipation is ~9.75 W. To limit T_j to 130 °C with ambient at 60 °C, total thermal resistance (junction-to-ambient) must be ≤7.2 °C/W. With R_th(j-c) = 1.55 °C/W, heatsink-to-ambient resistance must be ≤5.65 °C/W-typically requiring ≥10 cm² of 2 mm thick aluminum.

Can STPS20SM120ST be used in place of a 100 V Schottky diode in an existing design?

Only if reverse voltage stress remains ≤120 V. While V_RRM is higher, forward voltage is slightly elevated vs. 100 V parts (e.g., STPS20H100CT: V_F ≈ 0.58 V). Layout and thermal design must be re-validated due to different power loss profile and avalanche behavior.