STMicroelectronics STTH112

Overview

STTH112 from STMicroelectronics is a high-voltage ultrafast planar silicon rectifier diode rated for 1200 V repetitive peak reverse voltage, 1 A average forward current at 85 °C, and 75 ns reverse recovery time at 25 °C - optimized for snubber, clamping, and freewheeling in offline switch-mode power supplies.

For engineers reviewing the STTH112 datasheet, STTH112 pinout, STTH112 application, or STTH112 equivalent, key selection criteria include soft-switching EMI performance, junction-to-lead thermal resistance (45 °C/W in DO-41), low forward voltage drop (1.65 V max at 1 A/125 °C), and reliability under surge conditions (20 A IFSM, 8.3 ms).

Technical Context

The STTH112 employs ST's proprietary planar ultrafast technology to achieve soft reverse recovery with low stored charge (Qrr not specified but implied by trr = 75 ns), minimizing switching losses and EMI in high-frequency power converters operating up to 100 kHz. Its 175 °C maximum junction temperature enables operation in thermally constrained environments without derating penalties typical of standard fast recovery diodes.

It supports multiple package variants - DO-41 (0.34 g), SMA (0.068 g), and SMB (0.11 g) - each with validated thermal impedance curves (Rth(j-l): 45/30/25 °C/W respectively) and UL 94 V0-compliant epoxy encapsulation, enabling layout flexibility across cost-sensitive consumer and industrial power designs.

Key Specifications

Pinout & Package

STTH112 is a two-terminal axial-lead diode in DO-41 package (also available as surface-mount SMA and SMB variants). Cathode is marked by a band on the body. No internal pins - anode and cathode are accessed via leads.

Key Features

Applications

Availability

STTH112 is available at Aetrix Electronics and suitable for offline AC-DC adapters, industrial SMPS outputs, and snubber networks requiring stable component supply across long-life production cycles.

Supply support for STTH112 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The STTH series targets high-efficiency, high-reliability power conversion - specifically engineered for ultrafast recovery in hard- and soft-switched topologies where EMI and thermal stress dominate design constraints.

FAQ

What is the cathode marking convention for STTH112?

The cathode is identified by a single color band on the diode body. In DO-41 packaging, the banded lead is the cathode; in SMA/SMB variants, the band aligns with the cathode pad on the PCB footprint. This marking is consistent across all STTH112 variants and complies with JEDEC standards.

Can STTH112 replace STTH1R06 in a 600 V design?

No - STTH1R06 is rated for 600 V VRRM and has different recovery characteristics (trr ≈ 35 ns). STTH112's 1200 V rating and 75 ns trr make it unsuitable as a direct replacement unless the circuit requires higher voltage margin and can tolerate slower recovery. Thermal and conduction losses also differ significantly.

Is STTH112 suitable for synchronous rectification?

No - STTH112 is a passive PN-junction diode and cannot be actively controlled. Synchronous rectification requires a MOSFET with gate drive capability. Its ultrafast recovery is intended for passive rectification and clamping, not gate-driven switching.

How does thermal performance differ between DO-41 and SMB packages?

DO-41 has Rth(j-l) = 45 °C/W; SMB improves this to 25 °C/W due to larger copper pad area and shorter thermal path. At 1 A IF(AV), SMB runs ~20 °C cooler than DO-41 on identical FR4 PCBs - critical for compact, sealed power supplies where airflow is absent.