BFR30LT1 Equivalent & Substitute Parts

Part Overview

The BFR30LT1 is an N-Channel JFET transistor manufactured by onsemi, housed in a SOT-23-3 surface mount package. This device is rated for 225 mW power dissipation with a maximum drain-source voltage of 25 V and is designed for general-purpose switching and amplification applications. The part is currently listed as obsolete, making identification of suitable substitute components essential for ongoing design support and production continuity.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	25	V
Current - Drain (Idss) @ Vds, Vgs=0	4 mA @ 10 V	mA
Voltage - Cutoff (VGS off) @ Id	5 V @ 0.5 nA	V
Input Capacitance (Ciss) @ Vds	5 pF @ 10 V	pF
Power - Max	225	mW
Operating Temperature Range	-55 to 150	°C
Package / Case	SOT-23-3	—
Mounting Type	Surface Mount	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the BFR30LT1 is determined by the following critical parameters:

FET Type & Configuration: N-Channel JFET technology
Package Compatibility: SOT-23-3 (TO-236-3, SC-59) surface mount package
Voltage Rating: Maximum Vdss of 25 V or greater
Power Dissipation: Minimum 225 mW capability
Operating Temperature: -55°C to 150°C range
Drain Current (Idss): Specified at rated Vds and Vgs=0

The substitute parts identified below maintain compatibility across these parameters while offering active product status and improved compliance certifications.

Parameter Comparison

Parameter	BFR30LT1	MMBF5457	MMBF5484	MMBF5485	MMBFJ108	MMBFJ110
FET Type	N-Channel JFET	N-Channel JFET	N-Channel JFET	N-Channel JFET	N-Channel JFET	N-Channel JFET
Vdss (V)	25	25	25	25	25	25
Idss @ Vds (mA)	4 @ 10 V	1 @ 15 V	5 @ 15 V	10 @ 15 V	80 @ 15 V	10 @ 15 V
VGS(off) (V)	5 @ 0.5 nA	0.5 @ 10 nA	—	—	3 @ 10 nA	4 @ 10 nA
Ciss @ Vds (pF)	5 @ 10 V	7 @ 15 V	—	—	—	—
Power - Max (mW)	225	350	400	400	350	460
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

All identified substitute parts maintain the SOT-23-3 package footprint and N-Channel JFET configuration required for direct replacement of the BFR30LT1. The following factors support substitution decisions:

MMBF5457: Offers 350 mW power rating with lower Idss (1 mA @ 15 V) compared to the original part. Active product status with ROHS3 compliance. Suitable for applications requiring lower drain current characteristics.

MMBF5484: Rated for 400 mW with 5 mA Idss @ 15 V and 400 MHz frequency capability. Active status with ROHS3 compliance. Provides enhanced power handling for RF applications.

MMBF5485: Delivers 400 mW power dissipation with 10 mA Idss @ 15 V and 400 MHz frequency response. Active product with ROHS3 compliance. Increased current rating supports higher-current switching applications.

MMBFJ108: Provides 350 mW power rating with 80 mA Idss @ 15 V and 8 Ohm RDS(On). Active status with ROHS3 compliance. Highest drain current option for low-impedance switching circuits.

MMBFJ110: Rated for 460 mW with 10 mA Idss @ 15 V and 18 Ohm RDS(On). Active product with ROHS3 compliance. Highest power dissipation rating among substitutes.

All substitute parts are ROHS3 compliant and REACH unaffected, addressing regulatory requirements not met by the obsolete BFR30LT1.

Frequently Asked Questions (FAQ)

Q: Can MMBF5457 directly replace BFR30LT1 in all applications?

A: MMBF5457 maintains identical Vdss (25 V), operating temperature range (-55°C to 150°C), and SOT-23-3 package. However, Idss is lower (1 mA @ 15 V versus 4 mA @ 10 V). Substitution is valid where lower drain current does not compromise circuit function.

Q: What is the difference between MMBF5484 and MMBF5485?

A: Both parts share identical voltage ratings, temperature range, and 400 MHz frequency capability. The primary difference is drain current: MMBF5484 is rated for 5 mA while MMBF5485 is rated for 10 mA. Selection depends on circuit current requirements.

Q: Are all substitute parts available in the same packaging options?

A: MMBF5457 and MMBFJ108 are supplied in Cut Tape (CT) & Digi-Reel format. MMBFJ110, MMBF5485, and MMBF5486 are supplied in Tape & Reel (TR) format. MMBF5484 is available in Cut Tape & Digi-Reel. Packaging selection should align with production assembly requirements.

Q: Why is RoHS compliance important for BFR30LT1 substitution?

A: The original BFR30LT1 is RoHS non-compliant. All identified substitutes are ROHS3 compliant, meeting current environmental and regulatory standards for electronic component manufacturing and use.

Q: Which substitute part offers the highest power dissipation?

A: MMBFJ110 provides the highest power rating at 460 mW, followed by MMBF5484 and MMBF5485 at 400 mW each. Selection should be based on actual circuit power requirements rather than maximum rating alone.

Q: Can substitutes be used interchangeably in RF applications?

A: MMBF5484 and MMBF5485 are specified for 400 MHz operation with 4 dB noise figure, making them suitable for RF applications. MMBF5457, MMBFJ108, and MMBFJ110 lack frequency specifications and should be evaluated for specific RF performance requirements.

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