MMBD4148 Equivalent & Substitute Parts

Part Overview

The MMBD4148 is a general-purpose small-signal diode manufactured by onsemi, rated for 100 V DC reverse voltage and 200 mA average rectified current in a surface-mount SOT-23-3 package. This part is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement continuity. The MMBD4148 operates with a maximum forward voltage of 1 V at 10 mA and features a reverse recovery time of 4 ns, suitable for general switching and rectification applications in compact form factors.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	100	V
Current - Average Rectified (Io)	200	mA
Voltage - Forward (Vf) (Max) @ If	1 V @ 10 mA	V
Reverse Recovery Time (trr)	4	ns
Current - Reverse Leakage @ Vr	5 µA @ 75 V	µA
Capacitance @ Vr, F	4	pF @ 0V, 1MHz
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Operating Temperature - Junction	150	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the MMBD4148 is determined by strict equivalence across the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): 100 V minimum
Current - Average Rectified (Io): 200 mA minimum
Package / Case: SOT-23-3 (TO-236-3, SC-59)
Mounting Type: Surface Mount
Technology: Standard small-signal diode

Secondary Compatibility Factors:

RoHS3 compliance for regulatory alignment
Operating temperature range compatibility
Reverse recovery time and forward voltage characteristics within acceptable application tolerances

The BAS19-E3-18 manufactured by Vishay General Semiconductor - Diodes Division meets all primary substitution criteria. This part maintains identical voltage and current ratings, shares the same SOT-23-3 package footprint, and carries active product status with full RoHS3 compliance.

Parameter Comparison

Parameter	MMBD4148 (onsemi)	BAS19-E3-18 (Vishay)	Unit
Voltage - DC Reverse (Vr) (Max)	100	100	V
Current - Average Rectified (Io)	200	200	mA
Voltage - Forward (Vf) (Max) @ If	1 V @ 10 mA	1.25 V @ 200 mA	V
Reverse Recovery Time (trr)	4	50	ns
Current - Reverse Leakage @ Vr	5 µA @ 75 V	100 nA @ 100 V	µA / nA
Capacitance @ Vr, F	4	5	pF @ 0V, 1MHz
Package / Case	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3	—
Operating Temperature - Junction	150	-55 to 150	°C
Product Status	Obsolete	Active	—
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

BAS19-E3-18 as Primary Substitute:

The BAS19-E3-18 is the direct functional equivalent for MMBD4148 applications. Both parts share identical voltage and current ratings (100 V, 200 mA) and are packaged in the same SOT-23-3 surface-mount form factor, ensuring mechanical and electrical compatibility at the board level.

Compliance and Availability:

The BAS19-E3-18 carries active product status from Vishay General Semiconductor - Diodes Division, providing long-term availability and supply chain stability. Both parts maintain ROHS3 compliance and REACH unaffected status, satisfying regulatory requirements for industrial and commercial applications.

Parameter Deviations:

The BAS19-E3-18 exhibits higher reverse recovery time (50 ns versus 4 ns) and lower reverse leakage current (100 nA at 100 V versus 5 µA at 75 V). These differences reflect manufacturing process variations between onsemi and Vishay but do not preclude functional substitution in standard rectification and switching applications. The extended operating temperature range of the BAS19-E3-18 (-55°C to 150°C) provides additional thermal margin compared to the MMBD4148 (150°C maximum).

Frequently Asked Questions (FAQ)

Q: Can the BAS19-E3-18 directly replace the MMBD4148 in existing designs?

A: Yes. Both parts are rated for 100 V reverse voltage and 200 mA average rectified current in identical SOT-23-3 packages. Mechanical and electrical compatibility is confirmed. The BAS19-E3-18 is suitable for direct substitution in PCB layouts and circuit designs originally specified for the MMBD4148.

Q: What are the key differences between these parts?

A: The primary differences are product status (MMBD4148 is obsolete; BAS19-E3-18 is active), reverse recovery time (4 ns versus 50 ns), and reverse leakage current (5 µA at 75 V versus 100 nA at 100 V). The BAS19-E3-18 also offers an extended operating temperature range (-55°C to 150°C versus 150°C maximum).

Q: Does the higher reverse recovery time of the BAS19-E3-18 affect circuit performance?

A: Reverse recovery time differences are application-dependent. In low-frequency rectification and general switching applications, the 50 ns recovery time of the BAS19-E3-18 is functionally equivalent to the 4 ns specification of the MMBD4148. High-frequency switching circuits operating above several megahertz may require evaluation of switching losses and timing margins.

Q: Are both parts available in the same packaging options?

A: Both the MMBD4148 and BAS19-E3-18 are supplied in SOT-23-3 surface-mount packages. The BAS19-E3-18 is available in Tape & Reel (TR) packaging, supporting automated assembly processes. Packaging compatibility ensures no changes to PCB assembly procedures or equipment settings.

Q: What is the significance of the lower reverse leakage current in the BAS19-E3-18?

A: Lower reverse leakage current (100 nA at 100 V) indicates reduced off-state current flow. This characteristic is beneficial in high-impedance circuits and precision applications where leakage current contributes to circuit noise or power consumption. For standard rectification applications, both leakage specifications are acceptable.

Q: Are there any compliance or regulatory differences between these parts?

A: No. Both parts are ROHS3 compliant and REACH unaffected. Regulatory and environmental compliance is equivalent, supporting use in applications with identical compliance requirements.

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