STMicroelectronics STPS40L15CT

Overview

STPS40L15CT from STMicroelectronics is a dual-center-tap Schottky rectifier optimized for OR-ing in redundant 3 V, 5 V, and 12 V power rails. It delivers 2×20 A average forward current per diode, 15 V repetitive peak reverse voltage, and a maximum forward voltage drop of 0.33 V at 125 °C/19 A - enabling low conduction loss in fault-tolerant power supplies.

For engineers reviewing the STPS40L15CT datasheet, STPS40L15CT pinout, STPS40L15CT application, or STPS40L15CT equivalent, key selection criteria include its TO-220AB package thermal resistance (R_th(j-c) = 0.85 °C/W total), avalanche-rated capability (13.14 kW peak), and dual-diode symmetry for balanced rail redundancy.

Technical Context

This device implements two independent Schottky diodes sharing a common cathode terminal (center-tap configuration), enabling bidirectional OR-ing control across parallel power sources. Its low V_F (0.28–0.52 V) and high I_FSM (310 A) support fast transient response and surge resilience without thermal runaway under T_j ≤ 125 °C.

The diode pair is rated for repetitive avalanche energy (P_ARM = 13.14 kW at t_p = 1 µs), with dV/dt immunity up to 10,000 V/µs - critical for preventing false turn-on during rail switching transients in telecom and server PSUs.

Key Specifications

Pinout & Package

STPS40L15CT is housed in a TO-220AB package with three terminals: two anodes (A1, A2) and one shared cathode (K). The case is electrically isolated and thermally conductive, designed for screw-mount heatsinking with recommended torque of 0.4–0.6 N·m.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar OR-ing diode applications.

Compared with STPS30L15CW and MBR4015CT, STPS40L15CT uniquely balances high current density (40 A), low thermal resistance (0.85 °C/W), and certified avalanche capability - making it optimal for space-constrained, mission-critical OR-ing where both efficiency and ruggedness are required.

Availability

STPS40L15CT is available at Aetrix Electronics and suitable for telecom power distribution, server redundant PSU, and industrial PLC power backup requiring stable component supply and long-term lifecycle support.

Supply support for STPS40L15CT 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, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

STPS40L15CT belongs to ST's STPS low-drop Schottky rectifier product line, engineered specifically for high-efficiency, high-reliability OR-ing and power-path management in fault-tolerant DC power systems.

FAQ

What is the maximum junction temperature and how is it enforced?

The absolute maximum junction temperature is 125 °C, defined to prevent thermal runaway when mounted on a heatsink. This limit is enforced via thermal derating curves in the datasheet: average forward current must be reduced above 75 °C ambient, and R_th(j-c) = 0.85 °C/W assumes proper mechanical mounting with 0.4–0.6 N·m torque on the TO-220AB tab.

Can STPS40L15CT be used in 24 V systems?

No - its V_RRM is rated at 15 V, with no guaranteed reverse-blocking margin beyond that. Using it in 24 V systems risks catastrophic breakdown during transients or ripple. It is strictly qualified for 3 V, 5 V, and 12 V OR-ing rails as stated in the official device summary.

Is the cathode terminal electrically isolated from the package tab?

Yes - the TO-220AB package features an electrically isolated metal tab. The cathode (K) is internally bonded to the tab but remains insulated from PCB ground unless explicitly connected. Isolation voltage is rated per JEDEC standards, supporting safe use in floating-rail configurations.

How does its avalanche rating compare to standard Schottky diodes?

Unlike most Schottky diodes, STPS40L15CT specifies P_ARM = 13,140 W at 1 µs - a measured, guaranteed avalanche energy. Standard Schottkys typically lack this rating and may fail catastrophically under voltage overshoot; this part safely clamps and recovers, eliminating need for external TVS devices in many OR-ing layouts.