STMicroelectronics STTH112U

Overview

STTH112U from STMicroelectronics is an ultrafast high-voltage silicon rectifier diode in SMB package, rated for 1200 V repetitive peak reverse voltage, 1 A average forward current at 125 °C, and 75 ns reverse recovery time at 25 °C. It delivers low forward voltage drop (1.65 V max at 1 A, 125 °C) and soft switching for EMI reduction in power supply snubber and freewheeling circuits.

For engineers reviewing the STTH112U datasheet, STTH112U pinout, STTH112U application, or STTH112U equivalent, key selection criteria include reverse recovery time, thermal resistance (25 °C/W junction-to-lead), surge current capability (18 A @ 8.3 ms), and SMB footprint compatibility with high-density PCB layouts.

Technical Context

This planar-technology rectifier uses a soft-recovery profile to minimize voltage overshoot and ringing during turn-off, critical in flyback and resonant converters. Its 75 ns trr and 500 ns tfr are measured under standardized conditions (IF = 0.5 A, Irr = 0.25 A, IR = 1 A), ensuring predictable commutation behavior in high-frequency switching topologies.

The device operates up to 175 °C junction temperature with Rth(j-l) = 25 °C/W (SMB), enabling compact thermal design in enclosed power supplies. Reverse leakage remains ≤50 µA at 125 °C and 1200 V, supporting reliable blocking in high-impedance clamp networks.

Key Specifications

Pinout & Package

SMB (Surface Mount Diode) package: molded epoxy body, cathode band marked, lead-free and RoHS-compliant per ECOPACK® specifications. Dimensions per Table 6: D = 3.30–3.95 mm, E = 5.10–5.60 mm, E1 = 4.05–4.60 mm, L = 0.75–1.50 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STTH112U, STTH1R06U trades 600 V blocking and faster recovery for reduced voltage headroom, while ES1J-M3/5AT offers superior speed in a thermally less efficient SMA package-neither matches the 1200 V/75 ns/25 °C/W balance of the STTH112U in high-voltage freewheeling roles.

Availability

STTH112U is available at Aetrix Electronics and suitable for switch-mode power supply freewheeling, RCD snubber clamping, and high-voltage DC link demagnetization requiring stable component supply and consistent SMB footprint sourcing.

Supply support for STTH112U 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 applications, with STTH112U optimized for ultrafast recovery and high-voltage blocking in compact surface-mount form factors.

FAQ

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

The STTH112U has a maximum junction temperature of 175 °C. Operating continuously at this limit reduces long-term reliability due to accelerated metallization diffusion and bond wire fatigue. For 10-year field life, ST recommends limiting Tj to ≤150 °C using appropriate PCB copper area and ambient airflow, as validated in Figure 6 of the datasheet.

Can STTH112U replace a standard PN junction rectifier in existing designs?

Yes, but only if the original part's VRRM, IF(AV), and trr requirements are met or exceeded. STTH112U's 75 ns trr and soft recovery reduce EMI versus standard rectifiers (e.g., 1N4007), but its VF is higher than Schottky types-verify conduction loss impact and ensure snubber components are re-optimized for faster switching.

Is the SMB package lead-free and RoHS-compliant?

Yes, STTH112U is manufactured in an ECOPACK®-compliant SMB package meeting RoHS Directive 2011/65/EU and lead-free soldering requirements. The epoxy meets UL 94 V0 flammability rating, and the cathode band marking is laser-etched for process traceability.

How does thermal resistance vary with PCB copper area?

Rth(j-a) decreases significantly with added copper under each lead: from ~110 °C/W on minimal pads to ~40 °C/W with 4 cm² total copper (2 cm² per lead), per Figure 7. For thermal design, use Rth(j-l) = 25 °C/W as the dominant path, and treat Rth(l-a) as variable based on board layout.