STTA112U Equivalent & Substitute Parts

Part Overview

The STTA112U is a general-purpose rectifier diode manufactured by STMicroelectronics, rated for 1200 V DC reverse voltage and 1 A average rectified current in a Surface Mount SMB (DO-214AA) package. This device is part of the TURBOSWITCH™ series and features fast recovery characteristics with a reverse recovery time of 115 ns.

The STTA112U is classified as obsolete. Identification of equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this component.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	1200	V
Current - Average Rectified (Io)	1	A
Voltage - Forward (Vf) (Max) @ If	1.65 V @ 1 A	V
Reverse Recovery Time (trr)	115	ns
Current - Reverse Leakage @ Vr	10	µA @ 1200 V
Package / Case	DO-214AA, SMB	—
Mounting Type	Surface Mount	—
Operating Temperature - Junction (Max)	125	°C

Substitute Part Grouping Explanation

Substitution of the STTA112U is determined by the following electrical and mechanical parameters:

Voltage Rating: Reverse voltage must equal or exceed 1200 V DC
Current Rating: Average rectified current must equal or exceed 1 A
Package Type: Surface Mount SMB (DO-214AA) package required for mechanical compatibility
Speed Classification: Fast recovery diode technology (≤ 500 ns, > 200 mA)
Forward Voltage: Operating point compatibility at 1 A forward current
Reverse Leakage: Leakage current performance at rated reverse voltage

The STTH112U meets all substitution criteria for the STTA112U within the allowed parameter ranges for this product category.

Parameter Comparison

Parameter	STTA112U (Main Part)	STTH112U (Substitute)	Unit
Manufacturer	STMicroelectronics	STMicroelectronics	—
Category	Diodes, Rectifiers	Diodes, Rectifiers	—
Voltage - DC Reverse (Vr) (Max)	1200	1200	V
Current - Average Rectified (Io)	1	1	A
Voltage - Forward (Vf) (Max) @ If	1.65 V @ 1 A	1.9 V @ 1 A	V
Speed	Fast Recovery ≤ 500 ns, > 200 mA	Fast Recovery ≤ 500 ns, > 200 mA	—
Reverse Recovery Time (trr)	115	75	ns
Current - Reverse Leakage @ Vr	10	5	µA @ 1200 V
Package / Case	DO-214AA, SMB	DO-214AA, SMB	—
Mounting Type	Surface Mount	Surface Mount	—
Operating Temperature - Junction (Max)	125	175	°C
Product Status	Obsolete	Active	—
RoHS Status	RoHS non-compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

The STTH112U is a direct substitute for the STTA112U based on electrical and mechanical parameter equivalence. Both devices share identical voltage and current ratings, package configuration, and fast recovery speed classification.

The STTH112U offers the following advantages:

Active Product Status: The STTH112U is an active product with established supply chain availability, addressing the obsolescence of the STTA112U
Improved Thermal Performance: Maximum junction temperature of 175°C compared to 125°C provides enhanced thermal margin
Enhanced Reverse Recovery: Reverse recovery time of 75 ns is superior to the STTA112U specification of 115 ns, resulting in reduced switching losses
Reduced Reverse Leakage: Reverse leakage current of 5 µA at 1200 V is lower than the STTA112U specification of 10 µA
Regulatory Compliance: ROHS3 compliance status supports modern manufacturing and environmental requirements

The STTH112U forward voltage specification of 1.9 V at 1 A is higher than the STTA112U specification of 1.65 V at 1 A. This parameter difference must be evaluated within the context of the specific application circuit to ensure compatibility with voltage drop budgets and thermal dissipation requirements.

Frequently Asked Questions (FAQ)

Q: Can the STTH112U be used as a direct replacement for the STTA112U in existing designs?

A: The STTH112U meets the electrical and mechanical substitution criteria for the STTA112U. Both devices are rated for 1200 V reverse voltage, 1 A average rectified current, and use the identical DO-214AA SMB surface mount package. The forward voltage difference of 0.25 V must be evaluated within the application circuit design to confirm compatibility.

Q: What is the significance of the reverse recovery time difference between these parts?

A: The STTH112U has a reverse recovery time of 75 ns compared to the STTA112U specification of 115 ns. This 40 ns improvement reduces switching losses and improves efficiency in high-frequency switching applications. Applications operating at lower switching frequencies may not require this performance advantage.

Q: Why is the STTH112U forward voltage higher than the STTA112U?

A: The STTH112U is classified as an ultrafast diode with improved reverse recovery characteristics. The forward voltage specification of 1.9 V at 1 A reflects the trade-off between reverse recovery performance and forward conduction characteristics inherent to ultrafast diode technology.

Q: Are there any package or mounting differences between these parts?

A: Both the STTA112U and STTH112U use the DO-214AA SMB surface mount package. No package or mounting modifications are required for substitution. The STTH112U is available in Cut Tape (CT) and Digi-Reel® packaging formats.

Q: What is the impact of the higher maximum junction temperature of the STTH112U?

A: The STTH112U maximum junction temperature of 175°C compared to the STTA112U specification of 125°C provides an additional 50°C thermal margin. This allows operation in higher ambient temperature environments or with higher power dissipation levels while maintaining reliable device performance.

Q: Does the STTH112U meet current regulatory compliance requirements?

A: The STTH112U is ROHS3 compliant, meeting current environmental and manufacturing regulations. The STTA112U is classified as RoHS non-compliant. For new designs or production requiring regulatory compliance, the STTH112U is the appropriate selection.

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