STMicroelectronics STTH110

Overview

STTH110 from STMicroelectronics is an ultrafast high-voltage planar silicon rectifier diode optimized for free-wheeling, clamping, snubbing, and demagnetization in switching power supplies. It delivers 1 A average forward current, 1000 V repetitive peak reverse voltage, 75 ns typical reverse recovery time, and operates up to 175 °C junction temperature - enabling robust performance in auxiliary power supplies and SMPS output stages.

For engineers reviewing the STTH110 datasheet, STTH110 pinout, STTH110 application, or STTH110 equivalent, key selection criteria include its soft-switching behavior (reduced EMI), low conduction loss profile (1.42 V typ. VF at 1 A, 150 °C), and dual-package availability (DO-41 and SMA) supporting thermal design flexibility across board-level power topologies.

Technical Context

The STTH110 employs ST's proprietary ultrafast planar technology to achieve controlled minority-carrier lifetime, resulting in soft reverse recovery with low peak reverse recovery current (Irr = 0.25 A) and minimal voltage overshoot. Its trr of 75 ns (typ.) and tfr of 300 ns (typ.) are specified under standardized conditions (IF = 0.5 A, dIF/dt = 50 A/µs), ensuring predictable commutation behavior in hard-switched converters.

Thermal performance is package-dependent: DO-41 offers Rth(j-l) = 45 °C/W and Rth(j-a) = 110 °C/W (no copper pad), while SMA provides Rth(j-l) = 30 °C/W and superior surface-mount thermal coupling. Both packages meet ECOPACK2 environmental compliance and UL 94 V0 flammability rating.

Key Specifications

Pinout & Package

STTH110 is a two-terminal axial (DO-41) or surface-mount (SMA) discrete diode. Cathode is marked by a band on DO-41; on SMA, cathode is the side opposite the flat edge (pin 1 = anode, pin 2 = cathode). Both packages use planar silicon die with epoxy encapsulation meeting UL 94 V0.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MUR110 and VS-1N5819HM3/81, STTH110 uniquely balances 1000 V capability, 75 ns soft recovery, and 1.42 V VF at 150 °C - making it optimal for high-reliability, high-frequency auxiliary and clamp functions where thermal margin and EMI control are prioritized.

Availability

STTH110 is available at Aetrix Electronics and suitable for switching power supplies, freewheeling circuits, and snubber networks requiring stable component supply across industrial, telecom, and consumer electronics production programs.

Supply support for STTH110 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.

The STTH series belongs to ST's high-voltage ultrafast rectifier product line, engineered specifically for reduced EMI and high thermal reliability in power conversion stages of offline and isolated DC-DC converters.

FAQ

What is the maximum allowable junction temperature for STTH110, and how does it affect PCB layout?

The STTH110 has a maximum junction temperature (Tj) of 175 °C. This rating permits operation in high-ambient environments without active cooling, but PCB layout must ensure adequate copper area under leads: for DO-41, ≥10 cm² per lead reduces Rth(j-a) from 110 to ~60 °C/W; for SMA, ≥4 cm² per pad achieves Rth(j-a) < 50 °C/W per ST's thermal curves.

Does STTH110 have a specified reverse recovery charge (Qrr), and how is it used in loss calculations?

Qrr is not directly specified in the DS3067 datasheet, but can be derived from trr and Irr using Qrr ≈ 0.5 × trr × Irr. With trr = 75 ns and Irr = 0.25 A, Qrr ≈ 9.4 nC. This value feeds into reverse recovery loss calculation: Erec = Qrr × VR × fsw, critical for estimating total switching loss in high-frequency SMPS designs above 200 kHz.

Can STTH110 be used as a replacement for standard PN-junction rectifiers like 1N4007 in high-frequency applications?

No - while both are 1000 V diodes, STTH110's 75 ns trr and soft recovery make it suitable for switching frequencies up to ~2 MHz, whereas 1N4007 (trr > 30 µs) causes severe switching loss and EMI above 10 kHz. Substitution requires verifying layout thermal relief, snubber sizing, and gate drive strength to handle faster di/dt.

How do the DO-41 and SMA variants differ in thermal performance and mounting requirements?

DO-41 has Rth(j-l) = 45 °C/W and requires axial through-hole mounting with 10 mm lead length; SMA has Rth(j-l) = 30 °C/W and uses surface-mount reflow with recommended footprint (5.43 × 2.63 mm). SMA enables higher power density and automated assembly, while DO-41 offers simpler prototyping and higher IFSM (20 A vs. 18 A), but demands larger board area and manual soldering.