STMicroelectronics STTH15S12D

Overview

STTH15S12D from STMicroelectronics is an ultrafast high-voltage silicon rectifier diode in TO-220AC package, rated for 1200 V repetitive peak reverse voltage and 15 A average forward current, with 27 ns typical reverse recovery time and 1.9 V typical forward voltage at 150 °C junction temperature. It serves as a boost diode in uninterruptible power supplies (UPS) where fast switching and low conduction loss are critical.

For engineers reviewing the STTH15S12D datasheet, STTH15S12D pinout, STTH15S12D application, or STTH15S12D equivalent, key selection criteria include reverse recovery time (27 ns typ), thermal resistance (1.4 °C/W), softness factor (≥2), reverse leakage (≤400 µA at 150 °C), and surge current capability (130 A, 10 ms).

Technical Context

The STTH15S12D employs ST's Turbo 2 1200 V technology to achieve ultrafast recovery with soft reverse recovery characteristics (S ≥ 2), minimizing EMI and voltage overshoot during turn-off. Its low R_th(j-c) of 1.4 °C/W enables efficient heat transfer to heatsinks under continuous 15 A operation at T_c = 100 °C.

Dynamic performance is characterized at IF = 15 A, VR = 600 V, dIF/dt = 200 A/µs, yielding Q_RR = 1300 nC and I_RM = 12–17 A. Static parameters include VF = 1.9 V (typ, Tj = 150 °C) and IR ≤ 400 µA (Tj = 150 °C, VR = VRRM).

Key Specifications

Pinout & Package

TO-220AC package with isolated tab (case), single-anode/single-cathode configuration. Mounting hole accepts M3 screw; recommended torque: 0.4–0.6 N·m. Epoxy meets UL94 V0.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultrafast high-voltage rectifier applications.

Compared with MUR1512CT and VS-15EWH12, the STTH15S12D offers optimal balance of ultrafast recovery (27 ns), low VF (1.9 V), and industry-standard TO-220AC footprint-making it preferred for cost-sensitive, space-constrained UPS and industrial rectifier designs requiring proven thermal and dynamic performance.

Availability

STTH15S12D is available at Aetrix Electronics and suitable for uninterruptible power supplies, industrial AC-DC converters, solar inverter DC-links, and welding power supplies requiring stable component supply and long-term manufacturability.

Supply support for STTH15S12D 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, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The STTH series belongs to ST's Turbo 2 ultrafast rectifier product line, engineered specifically for high-efficiency, high-reliability power conversion in UPS, PFC, and industrial motor drives where low QRR, soft recovery, and thermal robustness are essential.

FAQ

What is the maximum junction temperature and how does it affect derating?

The STTH15S12D has a maximum junction temperature (Tj) of 175 °C. Derating begins above Tc = 100 °C: IF(AV) decreases linearly to zero at Tc = 175 °C. At Tc = 125 °C, the average forward current must be reduced to ~10.5 A to maintain safe thermal operation.

Is the TO-220AC package electrically isolated?

Yes-the TO-220AC package used for STTH15S12D features an electrically isolated metal tab. The case (tab) is not internally connected to either anode or cathode, allowing direct heatsink mounting without insulation hardware while maintaining circuit isolation.

How does softness factor (S ≥ 2) improve system-level performance?

A softness factor ≥2 indicates gradual current decay during reverse recovery, reducing di/dt-induced voltage overshoot and electromagnetic interference. This lowers snubber component stress, eases EMI filter design, and improves reliability in high-dV/dt environments like UPS and welders.

Can STTH15S12D replace older STTH1512 in existing designs?

Yes-STTH15S12D is a direct replacement for STTH1512, offering identical TO-220AC package, pinout, and ratings (15 A, 1200 V), but with improved Turbo 2 technology: 27 ns trr (vs. 35 ns), lower VF (1.9 V vs. 2.1 V at 150 °C), and enhanced softness (S ≥ 2 vs. S ≈ 1.5).