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Home > Products > Discrete Semiconductor Products > Diodes > Rectifiers > Single Diodes

STMicroelectronics STTH512D

Name: STTH512D
Brand: STMicroelectronics
SKU: STTH512D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STTH512D

Manufacturer:: STMicroelectronics

Category:: Single Diodes

Package:: TO-220-2

Datasheet:: STTH512D.pdf

Description:: DIODE GEN PURP 1.2KV 5A TO220AC

Quantity:: RFQ Add To RFQ list

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Inventory:2,025

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Product details

Overview

STTH512D from STMicroelectronics is a 1200 V, 5 A ultrafast recovery rectifier diode in TO-220AC package, featuring 48 ns typical reverse recovery time (trr), 1.25 V typical forward voltage at 125 °C, and operation up to 175 °C junction temperature. It delivers low conduction and switching losses for high-frequency SMPS, UPS, and motor control freewheeling applications.

For engineers reviewing the STTH512D datasheet, STTH512D pinout, STTH512D application, or STTH512D equivalent, key selection criteria include reverse recovery softness (S factor = 2), 2000 VRMS insulated package rating, thermal resistance Rth(j-c) = 2.5 °C/W, and ECOPACK2 compliance for industrial reliability.

Technical Context

This diode employs an optimized epitaxial structure enabling ultrafast recovery with soft turn-off characteristics-critical for reducing EMI and voltage overshoot in hard-switched converters. Its low leakage current (<5 µA at 25 °C, <30 µA at 125 °C) enhances thermal stability under sustained high-voltage bias.

The device supports repetitive peak forward current of 60 A (5 µs square wave) and surge non-repetitive current of 55 A (10 ms sine), with junction-to-case thermal resistance of 2.5 °C/W enabling robust thermal management on standard heatsinks.

Key Specifications

Parameter	Value and Actual Design Meaning
VRRM	1200 V - Withstands repetitive reverse voltage up to 1200 V, suitable for 800 V DC bus systems with safety margin.
IF(AV)	5 A - Average forward current rating at TL = 145 °C, defining continuous rectification capability in thermally constrained layouts.
trr(typ.)	48 ns - Measured at IF = 5 A, dIF/dt = −200 A/µs, VR = 600 V; enables >100 kHz switching without excessive switching loss.
VF(typ.)	1.25 V at Tj = 150 °C, IF = 5 A - Low forward drop reduces conduction loss and improves system efficiency at elevated temperatures.
S factor	2 - Softness ratio (tb/ta) ensures gradual reverse recovery, minimizing voltage spikes and snubber stress in inductive loads.
Rth(j-c)	2.5 °C/W - Junction-to-case thermal resistance allows direct mounting to heatsink; enables 175 °C max Tj with ≤40 °C case rise at 5 A.
IRM	11–16 A - Peak reverse recovery current at Tj = 125 °C, critical for IGBT/MOSFET gate drive and snubber sizing.

Pinout & Package

TO-220AC package: insulated plastic housing with metal tab (cathode-connected), three leads-Anode (A), Cathode (K), and isolated tab (electrically floating, rated 2000 VRMS).

Pin/Terminal	Circuit Role	Design Meaning
Anode (Lead 1)	Forward current entry	Connected to AC input or switch node; must withstand full reverse voltage when off.
Cathode (Lead 2)	Forward current exit / output rail connection	Typically tied to positive DC bus; carries full load current and reverse recovery charge.
Tab (isolated metal surface)	Thermal interface / mechanical ground	Electrically isolated (2000 VRMS), used for heatsinking without requiring insulating pads in many layouts.

Key Features

Feature	Design Value
Ultrafast & soft recovery	trr = 48 ns with S factor = 2 - Reduces EMI generation and voltage overshoot during turn-off in flyback and PFC stages.
High junction temperature operation	Tj(max) = 175 °C - Enables compact thermal design in sealed enclosures or high-ambient environments like server PSUs.
Low leakage current	IR < 5 µA @ 25 °C, <30 µA @ 125 °C - Minimizes standby power loss and improves thermal runaway margin in parallel configurations.
ECOPACK2 compliance	Halogen-free, RoHS-compliant epoxy - Meets industrial environmental requirements without sacrificing thermal or electrical performance.
High pulsed current capability	IFRM = 60 A (5 µs), IFSM = 55 A (10 ms sine) - Supports inrush current handling and transient overload in motor drives and UPS hold-up.

Applications

UPS Systems

Server Power Supplies

Use Scenario: High-efficiency AC/DC front-end and battery charging rectification in double-conversion UPS units.

IC Role / Device Role / Timing Role: Ultrafast freewheeling diode in synchronous rectification and boost PFC stages.

Use Value: 48 ns trr and soft recovery minimize switching losses and EMI, enabling >96% efficiency at 50–100 kHz operation.

Use Scenario: Output rectification and OR-ing in redundant 12 V/48 V server PSUs with tight thermal constraints.

IC Role / Device Role / Timing Role: High-reliability output diode handling 5 A continuous load with 175 °C Tj capability.

Use Value: Low VF(1.25 V @ 150 °C) reduces conduction loss; 2.5 °C/W Rth(j-c) supports passive cooling in dense 1U chassis.

Industrial Motor Control

Snubber & Demagnetization Circuits

Use Scenario: Freewheeling path for IGBTs in 3-phase inverter legs driving HVAC compressors and pumps.

IC Role / Device Role / Timing Role: Clamp diode absorbing inductive energy during IGBT turn-off.

Use Value: 1200 V VRRM and 16 A IRM ensure safe operation across 600–800 V DC links with voltage transients.

Use Scenario: Snubber network and transformer demagnetization in flyback and resonant LLC converters.

IC Role / Device Role / Timing Role: Fast, soft-recovery path for stored magnetic energy dissipation.

Use Value: S factor = 2 prevents voltage ringing; 960 nC Qrr enables precise snubber capacitor sizing for minimal loss.

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultrafast recovery diode applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STTH812D	8 A IF(AV), same VRRM (1200 V), trr = 50 ns, Rth(j-c) = 2.0 °C/W	Higher current handling; requires larger heatsink footprint but supports higher-power SMPS designs.	Select when average load exceeds 5 A or thermal budget permits lower Rth(j-c) benefit.
IXYS MUR5120	5 A IF(AV), 1200 V VRRM, trr = 65 ns, VF = 1.35 V @ 125 °C, TO-220AC	Slower recovery and higher VF increase conduction and switching losses in high-frequency designs.	Acceptable where cost sensitivity outweighs efficiency targets, but verify EMI compliance at target switching frequency.

Compared with STTH812D and IXYS MUR5120, STTH512D offers optimal balance of 5 A rating, 48 ns trr, and 1.25 V VF at 150 °C-making it preferred for space-constrained, thermally aggressive 1–3 kW SMPS where soft recovery and low leakage are critical.

Availability

STTH512D is available at Aetrix Electronics and suitable for UPS systems, server power supplies, and industrial motor control applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for STTH512D 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 industrial, automotive, and consumer markets.

STTH512D belongs to ST's high-voltage ultrafast diode product line, engineered specifically for high-efficiency, high-reliability rectification in industrial power conversion systems operating at elevated temperatures and frequencies.

FAQ

What is the maximum allowable case temperature for STTH512D in continuous operation?

The STTH512D has a maximum junction temperature of 175 °C and a junction-to-case thermal resistance of 2.5 °C/W. For continuous 5 A operation, the case temperature must not exceed 137.5 °C to maintain Tj ≤ 175 °C-calculated as Tj = Tc + (P × Rth(j-c)), where conduction loss P ≈ 6.25 W at 1.25 V VF.

Is STTH512D pin-compatible with other TO-220AC diodes for drop-in replacement?

Yes-STTH512D uses standard TO-220AC mechanical dimensions and lead configuration (Anode–Cathode–Tab), matching industry-standard footprints. However, its ultrafast soft-recovery behavior differs from standard fast or standard recovery diodes, so layout parasitics and snubber values must be re-verified.

Does STTH512D require a thermal pad or insulator when mounted to a heatsink?

No insulator is required-the TO-220AC package features an electrically isolated metal tab rated for 2000 VRMS. Direct mounting to grounded heatsinks is permitted, simplifying thermal design and eliminating thermal interface resistance from insulating washers.

How does the softness factor (S = 2) impact circuit performance in motor drive inverters?

A softness factor of 2 indicates a gradual reverse recovery profile, which limits di/dt during turn-off and suppresses voltage overshoot across IGBTs. In motor drives, this reduces stress on switching devices, lowers EMI filter requirements, and improves system reliability under high dIF/dt conditions (>200 A/µs).

STTH512D Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-220-2

Packaging:: Tube

Product Status:: Active

Technology:: Standard

Voltage - DC Reverse (Vr) (Max):: 1200 V

Current - Average Rectified (Io):: 5A

Voltage - Forward (Vf) (Max) @ If:: 2.2 V @ 5 A

Speed:: Fast Recovery =< 500ns, > 200mA (Io)

Reverse Recovery Time (trr):: 95 ns

Current - Reverse Leakage @ Vr:: 5 µA @ 1200 V

Capacitance @ Vr, F:: -

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220AC

Operating Temperature - Junction:: 175°C (Max)

STTH512D FAQ

1.How can I place an order for STTH512D through Aetrix?

Please submit a Request for Quotation (RFQ) for STTH512D on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for STTH512D reliable?

The price and inventory of STTH512D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STTH512D is usually 5 days.

3.What payment methods are accepted for STTH512D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STTH512D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STTH512D?

STTH512D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STTH512D order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for STTH512D?

For technical support, including STTH512D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STTH512D requirements.

6.How does Aetrix verify that STTH512D is sourced from the original manufacturer or authorized distributors?

All STTH512D products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that STTH512D meets industry standards.

7.What is the process for return or replacement of STTH512D?

All STTH512D units undergo pre-shipment inspection (PSI). If there is an issue with STTH512D, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The STTH512D part is unused and in its original packaging.

Return procedure for STTH512D:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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