MBR745 Schottky Diode Equivalent & Substitute Parts

Part Overview

The MBR745 is a 45V, 7.5A Schottky rectifier diode in TO-220-2 package configuration, manufactured by onsemi under the SWITCHMODE™ series. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for new designs and production continuity. The MBR745 serves as a fast recovery rectifier suitable for power supply and switching applications requiring low forward voltage drop and rapid switching characteristics.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) Maximum	45	V
Current - Average Rectified (Io)	7.5	A
Voltage - Forward (Vf) Maximum @ If	840 mV @ 15 A	mV @ A
Speed - Fast Recovery	≤ 500ns, > 200mA (Io)	ns
Current - Reverse Leakage @ Vr	100	µA @ 45 V
Mounting Type	Through Hole	—
Package / Case	TO-220-2	—
Operating Temperature - Junction	-65 to 175	°C
Technology	Schottky	—

Substitute Part Grouping Explanation

Substitution of the MBR745 is determined by the following critical parameters: reverse voltage rating (45V minimum), average rectified current (7.5A minimum), fast recovery speed characteristic (≤500ns), forward voltage drop characteristics, reverse leakage current, and through-hole TO-220-2 package compatibility. Parts are grouped into three categories:

Direct Equivalents (Identical Electrical and Package Specifications): Parts meeting all electrical parameters at 45V/7.5A with matching TO-220-2 package configuration and fast recovery characteristics.

Compatible Substitutes (Higher Current Rating): Parts rated for 45V with current ratings of 10A or higher, maintaining fast recovery speed and compatible package form factors. These provide enhanced current capacity while maintaining voltage and switching speed specifications.

Partial Substitutes (Reduced Voltage Rating): Parts rated at 40V with 7.5A current, suitable for applications where the full 45V rating is not required, maintaining all other critical electrical characteristics.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vr (Max) V	Io (A)	Vf (Max) mV @ If	Speed (ns)	Ir @ Vr (µA)	Package	Product Status	RoHS Status
MBR745	onsemi	45	7.5	840 @ 15A	≤500	100 @ 45V	TO-220-2	Obsolete	Non-compliant
MBR745G	onsemi	45	7.5	840 @ 15A	≤500	100 @ 45V	TO-220-2	Active	ROHS3 Compliant
MBR745 (Taiwan Semiconductor)	Taiwan Semiconductor Corporation	45	7.5	—	≤500	100 @ 45V	TO-220-2	Active	ROHS3 Compliant
MBR745-E3/45	Vishay General Semiconductor - Diodes Division	45	7.5	840 @ 15A	≤500	100 @ 45V	TO-220-2	Active	ROHS3 Compliant
STPS745D	STMicroelectronics	45	7.5	840 @ 15A	≤500	100 @ 45V	TO-220-2	Active	ROHS3 Compliant
MBR745-BP	Micro Commercial Co	45	7.5	—	≤500	100 @ 45V	TO-220-2	Active	—
MBR740-BP	Micro Commercial Co	40	7.5	—	≤500	100 @ 40V	TO-220-2	Active	—
DSS10-0045B	IXYS	45	10	510 @ 10A	≤500	5 @ 45V	TO-220-2	Active	ROHS3 Compliant
DSS10-0045A	IXYS	45	10	680 @ 10A	≤500	300 @ 45V	TO-220-2	Active	ROHS3 Compliant
VT2045BP-M3/4W	Vishay General Semiconductor - Diodes Division	45	20	660 @ 20A	≤500	2 @ 45V	TO-220-2	Active	ROHS3 Compliant
MBR1040F-BP	Micro Commercial Co	40	10	550 @ 10A	≤500	500 @ 40V	TO-220-2 Isolated Tab	Active	—

Engineering Selection Recommendations

Primary Direct Equivalent: MBR745G (onsemi) provides identical electrical specifications to the obsolete MBR745 with active product status and ROHS3 compliance. This part maintains the SWITCHMODE™ series designation and is the recommended replacement for direct substitution in existing designs.

Alternative Direct Equivalents: MBR745-E3/45 (Vishay) and STPS745D (STMicroelectronics) offer equivalent electrical performance with active status and full ROHS3 compliance. Both parts maintain 45V/7.5A ratings with identical fast recovery characteristics and are suitable for new designs requiring compliance certification.

Secondary Option - Taiwan Semiconductor MBR745: Active status with ROHS3 compliance and matching electrical specifications, though forward voltage characteristics are not specified in available documentation.

Micro Commercial Co Variants: MBR745-BP provides identical 45V/7.5A specifications with active status. MBR740-BP offers reduced voltage rating (40V) suitable for applications not requiring full 45V capability.

Higher Current Alternatives: DSS10-0045B (IXYS) and VT2045BP-M3/4W (Vishay) provide 45V rating with increased current capacity (10A and 20A respectively), suitable for applications requiring enhanced current handling while maintaining voltage specifications. These parts are ROHS3 compliant and active.

Reduced Voltage Option: MBR1040F-BP (Micro Commercial Co) rated at 40V/10A with isolated tab package variant, suitable for applications where 40V rating is acceptable and isolation is required.

Frequently Asked Questions (FAQ)

Q: Can MBR745G directly replace the obsolete MBR745?

A: Yes. MBR745G maintains identical electrical specifications (45V, 7.5A, 840mV forward voltage @ 15A, ≤500ns recovery time) and TO-220-2 package configuration. The primary difference is active product status and ROHS3 compliance certification.

Q: What is the difference between MBR745-E3/45 and STPS745D?

A: Both parts meet identical electrical specifications for the MBR745 (45V, 7.5A, 840mV Vf, ≤500ns recovery). The difference is manufacturer: MBR745-E3/45 is Vishay and STPS745D is STMicroelectronics. Both are ROHS3 compliant and active.

Q: Can DSS10-0045B be used as a substitute for MBR745?

A: DSS10-0045B is compatible for applications where higher current capacity (10A vs 7.5A) is beneficial or required. It maintains the 45V rating and fast recovery characteristics. Forward voltage is lower (510mV @ 10A) and reverse leakage is significantly lower (5µA @ 45V), making it suitable for designs requiring enhanced performance margins.

Q: What is the significance of the TO-220-2 package designation?

A: TO-220-2 indicates a through-hole package with two leads (anode and cathode), standard for power rectifier applications. All listed substitutes maintain this package form factor, ensuring mechanical and thermal compatibility with existing PCB layouts and heatsinking arrangements.

Q: Is MBR740-BP suitable for 45V applications?

A: MBR740-BP is rated for 40V maximum reverse voltage. It is suitable only for applications where the operating voltage does not exceed 40V. For designs requiring full 45V capability, use MBR745-BP or higher-rated alternatives.

Q: What does ROHS3 compliance indicate?

A: ROHS3 compliance certifies that the component meets Restriction of Hazardous Substances Directive requirements, restricting specified hazardous materials. This certification is required for many commercial and industrial applications. The obsolete MBR745 is non-compliant; all active substitutes listed are ROHS3 compliant.

Q: Why does VT2045BP-M3/4W have different forward voltage characteristics?

A: VT2045BP-M3/4W is rated for 20A current, double the MBR745 specification. Forward voltage is specified at 20A (660mV) rather than 15A, reflecting the higher current rating. This part is suitable for applications requiring significantly higher current capacity while maintaining 45V rating.

Q: Can isolated tab variants like MBR1040F-BP be used interchangeably?

A: MBR1040F-BP features an isolated tab (ITO-220AC package) versus standard TO-220-2. The isolated tab electrically separates the tab from the cathode lead, required for specific thermal management configurations. Use only when isolation is specified in the design requirements.

Q: What is the impact of reverse leakage current differences between substitutes?

A: Reverse leakage current affects power dissipation and circuit performance at high temperatures. Lower leakage (DSS10-0045B at 5µA, VT2045BP-M3/4W at 2µA) provides better performance margins. Higher leakage (MBR1040F-BP at 500µA) may require thermal management consideration in high-temperature applications.

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