MMBT5551-7 Equivalent & Substitute Parts

Part Overview

The MMBT5551-7 is a Surface Mount NPN Bipolar Junction Transistor (BJT) manufactured by Diodes Incorporated in SOT-23-3 package. This device is rated for 160V collector-emitter breakdown voltage with 600mA maximum collector current and 300MHz transition frequency. The part is currently discontinued at DiGi Electronics, necessitating identification of equivalent and substitute components for ongoing design and production requirements. Suitable alternatives must maintain electrical compatibility within the specified parameter ranges while meeting automotive-grade qualification standards.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	160	V
Current - Collector (Ic) (Max)	600	mA
Power - Max	300	mW
Frequency - Transition	300	MHz
Operating Temperature Range	-55 to 150	°C
Package / Case	SOT-23-3 (TO-236-3, SC-59)	—
Grade	Automotive	—
Qualification	AEC-Q101	—

Substitute Part Grouping Explanation

Substitution of the MMBT5551-7 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor Type: NPN (mandatory match)
Voltage - Collector Emitter Breakdown: minimum 160V (equal or greater)
Current - Collector (Ic) (Max): minimum 600mA (equal or greater)
Package / Case: SOT-23-3 compatible (TO-236-3, SC-59)
Operating Temperature Range: -55°C to 150°C minimum (equal or greater)
Mounting Type: Surface Mount (mandatory match)
Grade: Automotive with AEC-Q101 qualification (preferred for direct equivalence)

Secondary Compatibility Parameters:

Power dissipation rating (300mW minimum)
Frequency - Transition (300MHz preferred, lower acceptable for non-frequency-critical applications)
Vce Saturation characteristics
DC Current Gain (hFE)

Substitute parts are grouped into two categories: Direct Equivalents (matching all primary criteria with active product status) and Functional Alternatives (meeting electrical requirements with parameter trade-offs).

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) V	Power mW	Freq MHz	Temp °C	Package	Status	RoHS
MMBT5551-7	Diodes Inc.	600	160	300	300	-55 to 150	SOT-23-3	Discontinued	Non-compliant
MMBT5551-7-F	Diodes Inc.	600	160	300	300	-55 to 150	SOT-23-3	Active	Compliant
MMBT5551LT1G	onsemi	600	160	225	—	-55 to 150	SOT-23-3	Active	Compliant
MMBT5551LT3G	onsemi	600	160	225	—	-55 to 150	SOT-23-3	Active	Compliant
CMPT5551 TR PBFREE	Central Semiconductor	600	160	350	300	-65 to 150	SOT-23-3	Active	Compliant
MMBT5551-TP	Micro Commercial Co	600	160	300	100	-55 to 150	SOT-23-3	Active	Compliant
MMBT5551_R1_00001	Panjit International	600	160	250	300	-55 to 150	SOT-23-3	Active	Compliant
BSR19A,215	Nexperia USA Inc.	300	160	250	300	-55 to 150	SOT-23-3	Active	Compliant
MMBT5550LT1G	onsemi	600	140	225	—	-55 to 150	SOT-23-3	Active	Compliant
MMBT5550LT3G	onsemi	600	140	225	—	-55 to 150	SOT-23-3	Active	Compliant
MMBT2484LT1G	onsemi	100	60	225	—	-55 to 150	SOT-23-3	Active	Compliant
MMBT2484LT3G	onsemi	100	60	225	—	-55 to 150	SOT-23-3	Active	Compliant

Engineering Selection Recommendations

Direct Equivalents (Recommended Primary Substitutes):

MMBT5551-7-F (Diodes Incorporated) is the direct successor to the MMBT5551-7. This part maintains identical electrical specifications (160V, 600mA, 300MHz, 300mW) with active product status and RoHS3 compliance. The packaging format differs (Cut Tape & Digi-Reel versus standard packaging), but the component is electrically and mechanically interchangeable.

MMBT5551LT1G and MMBT5551LT3G (onsemi) provide full electrical compatibility with 160V breakdown voltage and 600mA collector current. These parts differ in power rating (225mW versus 300mW) and packaging format (Cut Tape or Tape & Reel). Both maintain AEC-Q101 automotive qualification and RoHS3 compliance. The reduced power rating is acceptable for applications not requiring the full 300mW dissipation margin.

CMPT5551 TR PBFREE (Central Semiconductor Corp) matches all primary electrical parameters with enhanced power rating (350mW) and extended lower temperature range (-65°C). This part is suitable for applications requiring additional thermal margin or lower temperature operation.

MMBT5551-TP (Micro Commercial Co) provides electrical equivalence with identical 160V/600mA ratings and 300mW power. The transition frequency is reduced to 100MHz, limiting this part to applications not requiring 300MHz performance.

MMBT5551_R1_00001 (Panjit International Inc.) offers full parameter compatibility with 160V/600mA ratings and 300MHz transition frequency. Power rating is 250mW, acceptable for most applications.

Functional Alternatives (Limited Substitution):

BSR19A,215 (Nexperia USA Inc.) maintains 160V breakdown voltage and 300MHz transition frequency but is limited to 300mA maximum collector current. This part is suitable only for applications requiring less than 300mA collector current.

MMBT5550LT1G and MMBT5550LT3G (onsemi) provide 600mA collector current with reduced breakdown voltage (140V versus 160V). These parts are suitable for applications with maximum operating voltage below 140V.

MMBT2484LT1G and MMBT2484LT3G (onsemi) are not recommended as substitutes. These parts are limited to 100mA collector current and 60V breakdown voltage, falling significantly below the MMBT5551-7 specifications.

Selection Criteria by Application:

For applications requiring full parameter equivalence with active product status, select MMBT5551-7-F or MMBT5551LT1G/LT3G.

For applications with reduced power dissipation requirements, MMBT5551LT1G/LT3G are acceptable.

For applications requiring extended temperature range, select CMPT5551 TR PBFREE.

For applications with collector current requirements below 300mA, BSR19A,215 is acceptable.

For applications with maximum operating voltage below 140V, MMBT5550LT1G/LT3G are acceptable.

Frequently Asked Questions (FAQ)

Q: Can MMBT5551-7-F be used as a direct replacement for MMBT5551-7?

A: Yes. MMBT5551-7-F is the active production equivalent with identical electrical specifications (160V, 600mA, 300MHz, 300mW). The only difference is packaging format (Cut Tape & Digi-Reel). Both are automotive-grade AEC-Q101 qualified.

Q: What is the difference between MMBT5551LT1G and MMBT5551LT3G?

A: Both parts are electrically identical with 160V breakdown voltage and 600mA collector current. The difference is packaging: LT1G is supplied in Cut Tape & Digi-Reel format, while LT3G is supplied in Tape & Reel format. Select based on your procurement and assembly requirements.

Q: Can I use MMBT5550LT1G/LT3G instead of MMBT5551-7?

A: MMBT5550 parts have reduced breakdown voltage (140V versus 160V). They are suitable only if your application operates at maximum voltages below 140V. The collector current rating (600mA) and package (SOT-23-3) are compatible.

Q: Why is BSR19A,215 listed as a substitute if it has only 300mA collector current?

A: BSR19A,215 is a functional alternative for applications requiring less than 300mA collector current. It maintains the 160V breakdown voltage and 300MHz transition frequency. It is not a direct equivalent due to the reduced current rating.

Q: Are MMBT2484LT1G and MMBT2484LT3G suitable replacements?

A: No. MMBT2484 parts are not suitable substitutes. They are limited to 100mA collector current and 60V breakdown voltage, both significantly below MMBT5551-7 specifications. These parts are only compatible with applications designed for lower voltage and current operation.

Q: What is the significance of RoHS compliance in selecting a substitute?

A: The original MMBT5551-7 is RoHS non-compliant. All active substitute parts listed are RoHS3 compliant. For new designs or applications with RoHS requirements, select from the RoHS3 compliant alternatives. For legacy applications without RoHS requirements, both compliant and non-compliant parts are acceptable.

Q: Does the reduced power rating in MMBT5551LT1G (225mW versus 300mW) affect compatibility?

A: The reduced power rating (225mW versus 300mW) provides less thermal margin but is acceptable for applications not requiring the full 300mW dissipation capability. Verify that your application's power dissipation does not exceed 225mW at maximum operating conditions.

Q: Can I use CMPT5551 TR PBFREE in applications requiring operation below -55°C?

A: Yes. CMPT5551 TR PBFREE has an extended lower temperature rating of -65°C versus -55°C for the MMBT5551-7. This part is suitable for applications requiring operation at temperatures below -55°C.

Q: What packaging formats are available for MMBT5551 equivalents?

A: Available packaging formats include Cut Tape (CT) & Digi-Reel, Tape & Reel (TR), and standard packaging. Select based on your assembly process requirements. All formats use the same SOT-23-3 component package.

Q: Is automotive qualification (AEC-Q101) required for all substitute parts?

A: The original MMBT5551-7 carries automotive-grade qualification. For automotive applications, select substitute parts with AEC-Q101 qualification. All primary substitute recommendations listed maintain this qualification.

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