MBR1240MFST1G Equivalent & Substitute Parts

Part Overview

The MBR1240MFST1G is a Schottky rectifier diode manufactured by onsemi, rated for 40 V DC reverse voltage and 12 A average rectified current in a 5-DFN surface mount package. This component is classified as obsolete product status. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for new production builds and field replacements where the original part is no longer readily procurable.

Key Parameters

Parameter	Value
Voltage - DC Reverse (Vr) (Max)	40 V
Current - Average Rectified (Io)	12 A
Voltage - Forward (Vf) (Max) @ If	680 mV @ 12 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr	500 µA @ 40 V
Technology	Schottky
Mounting Type	Surface Mount
Package / Case	8-PowerTDFN, 5 Leads
Supplier Device Package	5-DFN (5x6) (8-SOFL)
Operating Temperature - Junction	-55°C ~ 150°C
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the MBR1240MFST1G are qualified based on electrical and mechanical parameter equivalence. The following criteria determine substitution eligibility:

Electrical Parameters (Must Match):

Voltage - DC Reverse (Vr) (Max): 40 V
Current - Average Rectified (Io): 12 A
Voltage - Forward (Vf) (Max) @ If: 680 mV @ 12 A
Speed: Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr: 500 µA @ 40 V
Technology: Schottky

Mechanical Parameters (Must Match):

Mounting Type: Surface Mount
Package / Case: 8-PowerTDFN, 5 Leads
Supplier Device Package: 5-DFN (5x6) (8-SOFL)
Operating Temperature - Junction: -55°C ~ 150°C

Compliance Parameters (Must Match):

RoHS Status: ROHS3 Compliant
Moisture Sensitivity Level (MSL): 1 (Unlimited)

All substitute parts listed below meet these criteria and are therefore electrically and mechanically interchangeable with the MBR1240MFST1G.

Parameter Comparison

Parameter	MBR1240MFST1G	NRVB1240MFST1G	NRVB1240MFST3G
Manufacturer	onsemi	onsemi	onsemi
Technology	Schottky	Schottky	Schottky
Voltage - DC Reverse (Vr) (Max)	40 V	40 V	40 V
Current - Average Rectified (Io)	12 A	12 A	12 A
Voltage - Forward (Vf) (Max) @ If	680 mV @ 12 A	680 mV @ 12 A	680 mV @ 12 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr	500 µA @ 40 V	500 µA @ 40 V	500 µA @ 40 V
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Package / Case	8-PowerTDFN, 5 Leads	8-PowerTDFN, 5 Leads	8-PowerTDFN, 5 Leads
Supplier Device Package	5-DFN (5x6) (8-SOFL)	5-DFN (5x6) (8-SOFL)	5-DFN (5x6) (8-SOFL)
Operating Temperature - Junction	-55°C ~ 150°C	-55°C ~ 150°C	-55°C ~ 150°C
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
Product Status	Obsolete	Active	Active

Engineering Selection Recommendations

Primary Substitute: NRVB1240MFST1G

The NRVB1240MFST1G is the preferred substitute for the obsolete MBR1240MFST1G. This part maintains active product status with onsemi and is supplied in Tape & Reel (TR) packaging. All electrical and mechanical parameters are identical to the original part. The component carries ROHS3 compliance and MSL 1 rating, matching the original specification. Inventory availability is significantly higher (5047 pcs) compared to the original part.

Secondary Substitute: NRVB1240MFST3G

The NRVB1240MFST3G is an alternative substitute with identical electrical and mechanical specifications. This part also maintains active product status and carries equivalent compliance certifications. Inventory availability is lower (780 pcs) than the primary substitute. Both NRVB1240 variants are functionally equivalent and may be selected based on packaging preference and supply chain availability.

Frequently Asked Questions (FAQ)

Q: Can NRVB1240MFST1G and NRVB1240MFST3G be used interchangeably with MBR1240MFST1G?

A: Yes. Both substitute parts are electrically and mechanically equivalent. They share identical voltage ratings (40 V), current ratings (12 A), forward voltage characteristics (680 mV @ 12 A), switching speed (Fast Recovery ≤ 500ns), and package configuration (5-DFN 5x6). All three parts are ROHS3 compliant with MSL 1 rating.

Q: What is the difference between NRVB1240MFST1G and NRVB1240MFST3G?

A: The primary difference is packaging format. NRVB1240MFST1G is supplied in Tape & Reel (TR) format, while NRVB1240MFST3G packaging is not specified. All electrical and mechanical parameters are identical. Selection between these variants depends on assembly process requirements and supply availability.

Q: Why is the original MBR1240MFST1G classified as obsolete?

A: The MBR1240MFST1G has reached end-of-life status with the manufacturer. The NRVB1240 series represents the current active product line offering equivalent performance and specifications.

Q: Are there any thermal or performance differences between these parts?

A: No. All three parts share identical operating temperature range (-55°C ~ 150°C), forward voltage drop (680 mV @ 12 A), reverse leakage current (500 µA @ 40 V), and recovery speed characteristics (Fast Recovery ≤ 500ns, > 200mA).

Q: Can these diodes be used in high-frequency switching applications?

A: Yes. All three parts are classified as Fast Recovery Schottky diodes with recovery time ≤ 500ns at currents > 200mA, making them suitable for switching power supply and high-frequency rectification applications.

Q: What is the significance of the 5-DFN (5x6) package designation?

A: This indicates a 5-lead Dual Flat No-lead package with 5mm × 6mm footprint dimensions. All three parts use this identical package, ensuring PCB layout and assembly compatibility without modification.

Q: Are moisture sensitivity precautions required during handling?

A: All three parts carry MSL 1 (Unlimited) rating, indicating no moisture sensitivity restrictions. Standard handling procedures for surface mount components apply.

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