MMBF4393LT1 Equivalent & Substitute Parts

Part Overview

The MMBF4393LT1 is an N-channel JFET transistor manufactured by onsemi, rated for 30V operation with 0.225W power dissipation in a SOT-23 surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The MMBF4393LT1 remains available in inventory (2300 pcs), but active alternatives with compatible electrical and mechanical specifications are recommended for long-term supply chain stability.

Substiute Parts

MMBF4393LT1

onsemiIn Stock: 2402MMBF4393LT1 Datasheet

Current PartRFQ

MMBF4393LT1G

onsemiIn Stock: 125465MMBF4393LT1G Datasheet

DirectRFQ

CMPF4393 TR PBFREE

Central Semiconductor CorpIn Stock: 1570CMPF4393 TR PBFREE Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the MMBF4393LT1 is determined by the following critical parameters:

Electrical Compatibility Criteria:

• FET Type: N-Channel (required match)
• Drain to Source Voltage (Vdss): Minimum 30V (equal or higher acceptable)
• Current - Drain (Idss): 5 mA nominal range
• Voltage - Cutoff (VGS off): 500 mV nominal
• Input Capacitance (Ciss): 14 pF nominal
• Resistance - RDS(On): 100 Ohms nominal

Mechanical Compatibility Criteria:

• Package / Case: SOT-23-3 (TO-236) pinout compatibility
• Mounting Type: Surface Mount
• Moisture Sensitivity Level: MSL 1 (Unlimited)

Compliance Criteria:

• RoHS Status: ROHS3 Compliant preferred for new designs
• REACH Status: REACH Unaffected (acceptable)

Two substitute parts meet these criteria with varying electrical ratings and compliance improvements.

Parameter Comparison

Engineering Selection Recommendations

MMBF4393LT1G (onsemi) is the direct equivalent substitute. It maintains identical electrical specifications (30V Vdss, 0.225W power rating, 100 Ohms RDS(On)) and pinout compatibility in SOT-23-3 packaging. This part is currently in active production status with ROHS3 compliance, addressing the obsolescence and compliance limitations of the original MMBF4393LT1. Inventory availability is substantial (125,400 pcs), ensuring supply chain continuity.

CMPF4393 TR PBFREE (Central Semiconductor Corp) is a functional substitute with enhanced electrical ratings. It provides higher Drain to Source Voltage (40V vs. 30V) and increased power dissipation capability (0.350W vs. 0.225W), offering design margin improvement. The extended operating temperature range (-65°C to 150°C vs. -55°C to 150°C) provides additional thermal flexibility. This part is ROHS3 compliant and active in production. Selection of this substitute is appropriate when higher voltage or power headroom is required within the same SOT-23-3 package footprint.

Both substitutes are ROHS3 compliant and REACH unaffected, meeting modern regulatory requirements. The choice between MMBF4393LT1G and CMPF4393 TR PBFREE depends on whether the application requires exact electrical parameter matching (MMBF4393LT1G) or benefits from enhanced ratings (CMPF4393 TR PBFREE).

Frequently Asked Questions (FAQ)

Q: Can MMBF4393LT1G be used as a direct replacement for MMBF4393LT1?

A: Yes. MMBF4393LT1G is the direct onsemi equivalent with identical electrical specifications (30V Vdss, 0.225W power, 100 Ohms RDS(On)) and SOT-23-3 pinout. It is the recommended substitute for obsolete MMBF4393LT1 applications.

Q: What is the difference between MMBF4393LT1G and CMPF4393 TR PBFREE?

A: Both are N-channel JFETs in SOT-23-3 packages with 100 Ohms RDS(On). CMPF4393 TR PBFREE offers higher voltage rating (40V vs. 30V Vdss) and greater power dissipation (0.350W vs. 0.225W). MMBF4393LT1G maintains exact electrical parity with the original part.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. Both MMBF4393LT1G and CMPF4393 TR PBFREE are ROHS3 compliant. The original MMBF4393LT1 is RoHS non-compliant, making substitution necessary for applications requiring RoHS compliance.

Q: Do the substitute parts use the same SOT-23-3 pinout?

A: Yes. All substitute parts use SOT-23-3 (TO-236) packaging with identical pinout, enabling direct PCB footprint compatibility without layout modifications.

Q: Which substitute should be selected for new designs?

A: MMBF4393LT1G is recommended for direct replacement applications. CMPF4393 TR PBFREE is appropriate when design margins for voltage or power dissipation are beneficial. Both are active production parts with stable supply availability.

Q: What is the moisture sensitivity level for substitute parts?

A: Both substitutes have MSL 1 (Unlimited), matching the original part. No special moisture control measures are required during storage or handling.