STMicroelectronics STTH75S12W

Overview

STTH75S12W from STMicroelectronics is an ultrafast high-voltage silicon rectifier diode in DO-247 package, rated for 1200 V repetitive peak reverse voltage and 75 A average forward current at Tc = 80 °C, with 40 ns typical reverse recovery time and 1.9 V typical forward voltage at 150 °C - optimized as a boost diode in UPS power stages.

For engineers reviewing the STTH75S12W datasheet, STTH75S12W pinout, STTH75S12W application, or STTH75S12W equivalent, key selection criteria include reverse recovery softness (S = 1.2), thermal resistance (Rth(j-c) = 0.35 °C/W), surge capability (370 A IFSM), and low leakage (<2 mA at 150 °C).

Technical Context

The STTH75S12W employs ST's Turbo 2 1200 V process to achieve ultrafast switching with controlled soft recovery (S = 1.2), minimizing voltage overshoot and EMI during turn-off in hard-switched PFC and boost converters. Its low Rth(j-c) of 0.35 °C/W enables high-power dissipation with conductive cooling only.

Dynamic performance is characterized at IF = 75 A, VR = 600 V, dIF/dt = 200 A/µs, yielding QRR = 5300 nC and IRM = 26–37 A. Static VF remains stable across temperature: 1.9 V (typ) at 150 °C and 3.2 V (max) at 25 °C under 75 A DC.

Key Specifications

Pinout & Package

DO-247 package: isolated metal flange (cathode-connected case), axial lead configuration with M3 screw-mounting interface; thermal path optimized for direct heatsink attachment via 0.4–0.6 N·m torque.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MUR7512CT and VS-75E12, the STTH75S12W offers the lowest thermal resistance and tightest trr specification, making it optimal for high-efficiency, high-power-density UPS and solar inverter designs where thermal headroom and EMI control are critical.

Availability

STTH75S12W is available at Aetrix Electronics and suitable for uninterruptible power supply (UPS), solar photovoltaic inverters, industrial motor drives, and EV charging stations requiring stable component supply and long-term production continuity.

Supply support for STTH75S12W 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, microcontroller, and sensor solutions for automotive, industrial, and consumer markets.

The STTH series belongs to ST's high-voltage power diode product line, engineered specifically for ultrafast switching in high-efficiency AC/DC and DC/DC conversion systems operating above 600 V DC-link.

FAQ

What is the maximum allowable case temperature for continuous operation?

The STTH75S12W is rated for IF(AV) = 75 A at Tc = 80 °C per datasheet Table 2. Operation at higher case temperatures is possible but requires derating: at Tc = 100 °C, average current must be reduced to approximately 62 A to maintain Tj ≤ 175 °C, based on Rth(j-c) = 0.35 °C/W and VF(Tj) curve extrapolation.

Is the cathode flange electrically isolated from the heatsink mounting surface?

No - the cathode is internally bonded to the metal flange, which serves as both the electrical cathode terminal and primary thermal path. Electrical isolation from the heatsink requires a dielectric washer (e.g., mica or ceramic) and insulated mounting hardware; failure to isolate may cause short circuits in grounded-heatsink configurations.

Does STTH75S12W support paralleling for higher current capacity?

Paralleling is not recommended without external balancing: the device lacks inherent current-sharing features, and VF mismatch across units (±0.2 V) can cause uneven current distribution. If required, use matched lots, identical PCB layout, and individual series inductors (≥100 nH) to force dynamic sharing at switching frequencies above 20 kHz.

What is the recommended PCB footprint and thermal pad design?

ST specifies DO-247 mechanical dimensions in Table 6: flange diameter 3.55–3.65 mm, mounting hole center-to-center spacing 10.9 mm. For thermal performance, use ≥25 mm² copper area per side (2 oz Cu minimum), thermally connected to internal planes via ≥8 vias (0.3 mm drill), and avoid solder mask over the flange contact zone to ensure low-impedance thermal transfer.