Equivalent & Substitute Parts for Vishay 12TQ045 Schottky Diode

Part Overview

The Vishay 12TQ045 is a Schottky rectifier diode rated for 45 V DC reverse voltage and 15 A average rectified current in a TO-220AC package. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for new designs and production continuity. Equivalent parts maintain identical electrical and mechanical specifications, while substitute parts provide functional alternatives with modified performance characteristics within acceptable operating parameters.

Key Parameters

Parameter	Value
Voltage - DC Reverse (Vr) (Max)	45 V
Current - Average Rectified (Io)	15 A
Voltage - Forward (Vf) (Max) @ If	560 mV @ 15 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr	1.75 mA @ 45 V
Mounting Type	Through Hole
Package / Case	TO-220-2
Operating Temperature - Junction	-55°C ~ 150°C
Technology	Schottky

Substitute Part Grouping Explanation

Substitution of the Vishay 12TQ045 is determined by the following critical parameters:

Voltage Rating: All substitute parts maintain the 45 V DC reverse voltage specification, ensuring compatibility in circuits designed for this voltage class.

Current Rating: The original part is rated for 15 A average rectified current. Substitute parts with equal or higher current ratings (15 A or 16 A) are functionally compatible, as they can handle the specified load without exceeding thermal or electrical limits.

Package Type: All substitute parts use the TO-220-2 or TO-220AC package, maintaining identical mechanical fit and thermal interface characteristics.

Technology: All parts employ Schottky diode technology, preserving the fast recovery characteristics and forward voltage behavior required for the application.

Operating Temperature Range: Substitute parts with equal or extended temperature ranges maintain compatibility with the original thermal operating envelope.

Substitute parts are grouped into two categories: manufacturer-recommended substitutes with enhanced specifications (higher current ratings or improved compliance status) and parametric equivalents with identical electrical characteristics.

Parameter Comparison

Parameter	Vishay 12TQ045	IXYS DSS16-0045B	onsemi MBR1645G	STMicroelectronics STPS1545D
Voltage - DC Reverse (Vr) (Max)	45 V	45 V	45 V	45 V
Current - Average Rectified (Io)	15 A	16 A	16 A	15 A
Voltage - Forward (Vf) (Max) @ If	560 mV @ 15 A	480 mV @ 15 A	630 mV @ 16 A	840 mV @ 30 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr	1.75 mA @ 45 V	10 mA @ 45 V	200 µA @ 45 V	200 µA @ 45 V
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	TO-220-2	TO-220-2	TO-220-2	TO-220-2
Operating Temperature - Junction	-55°C ~ 150°C	-55°C ~ 150°C	-65°C ~ 175°C	Max 175°C
Product Status	Obsolete	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: STMicroelectronics STPS1545D

The STPS1545D is the direct parametric equivalent to the Vishay 12TQ045, maintaining identical voltage and current ratings of 45 V and 15 A respectively. This part is active in production status and ROHS3 compliant, addressing the obsolescence of the original component. The STPS1545D is available in high inventory quantities (35,200 pcs), ensuring supply chain continuity. The TO-220AC package provides direct mechanical compatibility with existing PCB layouts.

Secondary Recommendation: IXYS DSS16-0045B

The DSS16-0045B offers enhanced current capacity at 16 A while maintaining the 45 V voltage rating and identical operating temperature range. This part provides improved forward voltage characteristics (480 mV @ 15 A versus 560 mV @ 15 A), resulting in lower power dissipation. ROHS3 compliance and active product status support long-term availability. The DSS16-0045B is suitable for applications where thermal performance optimization is beneficial.

Tertiary Recommendation: onsemi MBR1645G

The MBR1645G provides 16 A current capacity and extended operating temperature range (-65°C to 175°C), offering thermal margin beyond the original specification. This part is ROHS3 compliant and maintains high inventory availability (17,020 pcs). The MBR1645G is appropriate for applications requiring extended temperature operation or higher current headroom. Forward voltage is higher at 630 mV @ 16 A, resulting in increased power dissipation compared to the original part.

Compliance Consideration: All three substitute parts are ROHS3 compliant, whereas the original Vishay 12TQ045 is RoHS non-compliant. This compliance upgrade is mandatory for new designs subject to RoHS regulations.

Frequently Asked Questions (FAQ)

Q: Can the STPS1545D directly replace the Vishay 12TQ045 without circuit modification?

A: Yes. The STPS1545D maintains identical voltage (45 V), current (15 A), and temperature specifications. The TO-220AC package provides mechanical compatibility. No circuit modifications are required.

Q: What is the difference between the IXYS DSS16-0045B and the original 12TQ045?

A: The DSS16-0045B has a higher current rating (16 A versus 15 A) and lower forward voltage (480 mV @ 15 A versus 560 mV @ 15 A). Both maintain 45 V voltage rating and identical temperature range. The higher current rating provides design margin without requiring circuit changes.

Q: Why does the onsemi MBR1645G have higher forward voltage than the original part?

A: Forward voltage is a characteristic of the specific diode design and manufacturing process. The MBR1645G's higher forward voltage (630 mV @ 16 A) results in increased power dissipation. This must be evaluated in thermal design calculations for applications with tight thermal budgets.

Q: Are all substitute parts available in the same package?

A: Yes. All substitute parts use the TO-220-2 or TO-220AC package, which are mechanically and thermally equivalent. PCB layout modifications are not required.

Q: What is the significance of the reverse leakage current differences?

A: The original 12TQ045 has reverse leakage of 1.75 mA @ 45 V. Substitute parts show higher leakage (10 mA for DSS16-0045B, 200 µA for MBR1645G and STPS1545D). Higher leakage increases standby power consumption and heat generation. Applications sensitive to leakage current should evaluate this parameter against circuit requirements.

Q: Which substitute part has the best thermal performance?

A: The onsemi MBR1645G offers the widest operating temperature range (-65°C to 175°C) and highest maximum junction temperature (175°C). The IXYS DSS16-0045B provides the lowest forward voltage (480 mV @ 15 A), resulting in the lowest power dissipation and heat generation at rated current.

Q: Are all substitute parts RoHS compliant?

A: Yes. All three substitute parts are ROHS3 compliant. The original Vishay 12TQ045 is RoHS non-compliant. This compliance upgrade is required for new designs and manufacturing in regulated markets.

Q: Can I use a 16 A rated diode in a circuit designed for 15 A?

A: Yes. A higher current rating provides design margin and does not create compatibility issues. The circuit will operate within the diode's safe operating area. Thermal design must account for actual power dissipation based on forward voltage characteristics.

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