MMBFJ271 JFET P-Channel Transistor Equivalent & Substitute Parts

Part Overview

The MMBFJ271 is a P-Channel JFET transistor rated for 30 V breakdown voltage and 225 mW maximum power dissipation in a surface mount SOT-23-3 package. This part is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across voltage ratings, current characteristics, and thermal operating ranges while accommodating packaging and availability constraints.

Key Parameters

Parameter	Value	Unit
Voltage - Breakdown (V(BR)GSS)	30	V
Current - Drain (Idss) @ Vds (Vgs=0)	6	mA @ 15 V
Voltage - Cutoff (VGS off) @ Id	1.5	V @ 1 nA
Power - Max	225	mW
Operating Temperature Range	-55 to 150	°C (TJ)
Package / Case	SOT-23-3	—
Mounting Type	Surface Mount	—
FET Type	P-Channel	—

Substitute Part Grouping Explanation

Substitution eligibility for the MMBFJ271 is determined by the following criteria:

Voltage Rating: All substitutes must maintain V(BR)GSS ≥ 30 V to ensure equivalent or superior voltage handling capability
Package Compatibility: All substitutes must use SOT-23-3 surface mount packaging to maintain PCB layout and assembly compatibility
FET Type: All substitutes must be P-Channel JFETs to preserve circuit functionality
Power Rating: Substitutes with power ratings ≥ 225 mW are acceptable; higher ratings provide thermal margin
Operating Temperature: All substitutes must support the -55°C to 150°C range or equivalent
Current and Voltage Characteristics: Idss and VGS(off) parameters may vary within acceptable design tolerances; RDS(On) values indicate on-state resistance performance

The following parts meet these substitution criteria: MMBFJ175LT1G, MMBFJ175LT3G, MMBFJ177LT1G, and CMPFJ176 TR.

Parameter Comparison

Parameter	MMBFJ271	MMBFJ175LT1G	MMBFJ175LT3G	MMBFJ177LT1G	CMPFJ176 TR
Manufacturer	onsemi	onsemi	onsemi	onsemi	Central Semiconductor Corp
Product Status	Obsolete	Active	Active	Active	Active
V(BR)GSS (V)	30	30	30	30	30
Idss @ 15 V (mA)	6	7	7	1.5	2
VGS(off) @ 10 nA (V)	1.5 @ 1 nA	3	3	0.8	1
RDS(On) (Ohms)	—	125	125	300	250
Power - Max (mW)	225	225	225	225	350
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-65 to 150
Package	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	RoHS non-compliant

Engineering Selection Recommendations

Primary Substitutes (onsemi ROHS3 Compliant):

MMBFJ175LT1G and MMBFJ175LT3G are functionally equivalent to MMBFJ271 with active product status and ROHS3 compliance. Both parts share identical voltage ratings, power dissipation, and operating temperature ranges. The primary difference is packaging format: MMBFJ175LT1G is supplied in Cut Tape (CT) & Digi-Reel format, while MMBFJ175LT3G is supplied in Tape & Reel (TR) format. Selection between these two depends on procurement and assembly requirements. Idss is slightly elevated at 7 mA compared to the original 6 mA specification, and RDS(On) is specified at 125 Ohms, indicating lower on-state resistance.

MMBFJ177LT1G is an active onsemi part with ROHS3 compliance and identical voltage and power ratings. This part exhibits lower Idss (1.5 mA) and lower VGS(off) (0.8 V), with higher RDS(On) (300 Ohms). Selection of this part is appropriate when lower leakage current is required.

Secondary Substitute (Non-ROHS Compliant):

CMPFJ176 TR is manufactured by Central Semiconductor Corp and maintains 30 V voltage rating with higher power dissipation (350 mW). This part is RoHS non-compliant and should be selected only when ROHS3 compliance is not a design requirement. Operating temperature range extends to -65°C, providing wider low-temperature capability.

Frequently Asked Questions (FAQ)

Q: Can MMBFJ175LT1G and MMBFJ175LT3G be used interchangeably with MMBFJ271?

A: Yes. Both parts are electrically equivalent with identical voltage ratings (30 V), power dissipation (225 mW), and operating temperature ranges (-55°C to 150°C). The difference is packaging format: CT & Digi-Reel versus Tape & Reel. PCB layout and circuit performance are identical.

Q: What is the difference between MMBFJ175LT1G and MMBFJ177LT1G?

A: Both are onsemi P-Channel JFETs in SOT-23-3 packages with 30 V ratings. MMBFJ175LT1G has Idss of 7 mA and RDS(On) of 125 Ohms. MMBFJ177LT1G has lower Idss (1.5 mA) and higher RDS(On) (300 Ohms). Selection depends on whether lower leakage current or lower on-state resistance is prioritized in the application.

Q: Is CMPFJ176 TR suitable for new designs?

A: CMPFJ176 TR is electrically compatible with MMBFJ271 and offers higher power dissipation (350 mW). However, it is RoHS non-compliant. Use this part only when ROHS3 compliance is not required by design specifications or regulatory requirements.

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

A: All substitute parts use SOT-23-3 surface mount packaging, ensuring PCB compatibility. However, they differ in supply format: MMBFJ175LT1G and MMBFJ177LT1G are available in Cut Tape & Digi-Reel format, while MMBFJ175LT3G is supplied in Tape & Reel format. Verify procurement format requirements with your supplier.

Q: What compliance certifications apply to these substitutes?

A: MMBFJ175LT1G, MMBFJ175LT3G, and MMBFJ177LT1G are ROHS3 compliant. CMPFJ176 TR is RoHS non-compliant. All parts are REACH unaffected and classified as EAR99 for export control purposes.

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