MMST3904Q-7-F Equivalent & Substitute Parts

Part Overview

The MMST3904Q-7-F is an NPN bipolar junction transistor manufactured by Diodes Incorporated, designed for general-purpose switching and amplification applications. This surface mount device operates at 40 V collector-emitter breakdown voltage with a maximum collector current of 200 mA and transition frequency of 300 MHz. The part is classified as Active product status with AEC-Q101 automotive qualification and ROHS3 compliance. Substitute parts are identified when equivalent electrical performance, mechanical compatibility, and regulatory compliance can be maintained across alternative manufacturers while preserving circuit functionality.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Collector-Emitter Breakdown Voltage (Max)	40	V
Collector Current (Max)	200	mA
Power Dissipation (Max)	200	mW
Transition Frequency	300	MHz
DC Current Gain (hFE Min)	100	@ 10mA, 1V
Vce Saturation (Max)	300	mV @ 5mA, 50mA
Package Type	SOT-323 (SC-70)	—
Operating Temperature Range	-55 to 150	°C
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution eligibility for the MMST3904Q-7-F is determined by strict equivalence across the following electrical and mechanical parameters:

Critical Matching Parameters:

Transistor Type: NPN
Collector-Emitter Breakdown Voltage: 40 V (maximum)
Collector Current: 200 mA (maximum)
DC Current Gain (hFE): 100 minimum at 10 mA, 1 V
Vce Saturation: 300 mV maximum at specified bias conditions
Package: SOT-323 (SC-70) surface mount configuration
RoHS Compliance: ROHS3 Compliant
Moisture Sensitivity: MSL 1 (Unlimited)

Allowable Variations:

Power dissipation may exceed 200 mW (higher ratings are acceptable)
Transition frequency may equal or exceed 300 MHz
Operating temperature range may be extended beyond -55 to 150°C
Packaging format may differ (Tape & Reel, Cut Tape, Digi-Reel) provided pinout and footprint remain compatible
Supplier device package designation may vary (SOT-323, SC-70, SC-70-3, UMT3) if mechanical compatibility is maintained

All identified substitutes maintain electrical equivalence and regulatory compliance with the primary part.

Parameter Comparison

Parameter	MMST3904Q-7-F (Diodes)	PMST3904,115 (Nexperia)	PMST3904,135 (Nexperia)	CMST3904 TR PBFREE (Central Semi)	MMBT3904W_R1_00001 (Panjit)	MMBT3904WT1G (onsemi)	UMT3904T106 (Rohm)
Transistor Type	NPN	NPN	NPN	NPN	NPN	NPN	NPN
Vce(BR) Max (V)	40	40	40	40	40	40	40
Ic Max (mA)	200	200	200	200	200	200	200
Power Max (mW)	200	200	200	275	150	150	200
Frequency - Transition (MHz)	300	300	300	300	—	300	300
hFE Min @ 10mA, 1V	100	100	100	100	100	100	100
Vce Sat Max (mV)	300	300	300	300	300	300	300
Package	SOT-323	SOT-323	SOT-323	SOT-323	SOT-323	SC-70	UMT3
Operating Temp Range (°C)	-55 to 150	to 150	to 150	-65 to 150	-55 to 150	-55 to 150	to 150
RoHS Status	ROHS3	ROHS3	ROHS3	ROHS3	ROHS3	ROHS3	ROHS3
MSL	1	1	1	1	1	1	1
AEC-Q101	Yes	Yes	Yes	—	—	—	—

Engineering Selection Recommendations

Primary Substitutes (Full Equivalence):

PMST3904,115 and PMST3904,135 (Nexperia USA Inc.) are direct electrical equivalents with identical electrical specifications and AEC-Q101 automotive qualification. Both parts maintain 40 V breakdown voltage, 200 mA collector current, 300 mV saturation voltage, and 300 MHz transition frequency. These parts are suitable for applications requiring automotive-grade components.

Secondary Substitutes (Electrical Equivalence with Specification Variations):

CMST3904 TR PBFREE (Central Semiconductor Corp) provides electrical equivalence with extended power dissipation rating (275 mW) and expanded operating temperature range (-65 to 150°C). This part lacks documented AEC-Q101 qualification but maintains all critical electrical parameters.

MMBT3904W_R1_00001 (Panjit International Inc.) and MMBT3904WT1G (onsemi) are electrically equivalent with reduced power dissipation ratings (150 mW). These parts are suitable for applications where power dissipation does not exceed 150 mW. MMBT3904WT1G maintains 300 MHz transition frequency specification.

UMT3904T106 (Rohm Semiconductor) provides electrical equivalence with alternative package designation (UMT3) while maintaining SOT-323 mechanical compatibility. This part specifies 300 MHz transition frequency and 200 mW power dissipation.

Selection Criteria:

For automotive applications requiring AEC-Q101 qualification: PMST3904,115 or PMST3904,135
For extended temperature range applications: CMST3904 TR PBFREE
For power-constrained applications: MMBT3904W_R1_00001 or MMBT3904WT1G
For alternative package sourcing: UMT3904T106

All substitutes maintain ROHS3 compliance and MSL 1 moisture sensitivity rating.

Frequently Asked Questions (FAQ)

Q: Can PMST3904,115 replace MMST3904Q-7-F in automotive applications?

A: Yes. PMST3904,115 maintains identical electrical specifications (40 V, 200 mA, 300 mV saturation, 300 MHz transition frequency) and carries AEC-Q101 automotive qualification equivalent to the primary part.

Q: What is the difference between MMBT3904W_R1_00001 and MMBT3904WT1G?

A: Both parts are electrically equivalent with 150 mW power dissipation ratings. MMBT3904WT1G specifies 300 MHz transition frequency, while MMBT3904W_R1_00001 does not document this parameter. Both maintain 40 V breakdown voltage, 200 mA collector current, and 300 mV saturation voltage.

Q: Is CMST3904 TR PBFREE suitable for all applications where MMST3904Q-7-F is used?

A: CMST3904 TR PBFREE is electrically equivalent with extended operating temperature range (-65 to 150°C versus -55 to 150°C) and higher power dissipation (275 mW). However, this part does not carry documented AEC-Q101 qualification. Suitability depends on application requirements for automotive certification.

Q: Are the package designations SOT-323, SC-70, and UMT3 mechanically compatible?

A: SOT-323 and SC-70 are equivalent package designations for the same physical form factor. UMT3 is an alternative package designation from Rohm Semiconductor that maintains mechanical compatibility with SOT-323 footprints. Pin configuration and lead spacing remain identical across these designations.

Q: What is the significance of the power dissipation difference between 150 mW and 200 mW ratings?

A: Power dissipation rating indicates maximum allowable heat generation. Parts rated at 150 mW (MMBT3904W_R1_00001, MMBT3904WT1G) are suitable for applications where actual power dissipation does not exceed 150 mW. Parts rated at 200 mW or higher accommodate higher power dissipation. Selection depends on circuit power requirements.

Q: Can I substitute MMST3904Q-7-F with UMT3904T106 in existing PCB designs?

A: Yes, provided the PCB footprint accommodates the UMT3 package designation. Both parts maintain SOT-323 mechanical compatibility and identical pin configuration. Electrical performance is equivalent across all critical parameters.

Q: What does MSL 1 (Unlimited) moisture sensitivity mean?

A: MSL 1 indicates the component has unlimited shelf life without moisture bake-out requirements. All identified substitutes carry MSL 1 rating, eliminating moisture-related handling constraints.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All identified substitute parts maintain ROHS3 compliance, consistent with the primary MMST3904Q-7-F part.

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