MMBT3904T Equivalent & Substitute Parts

Part Overview

The MMBT3904T is a surface mount NPN bipolar junction transistor manufactured by onsemi, rated for 40V collector-emitter breakdown voltage and 200mA maximum collector current. This component is classified as obsolete, which necessitates identification of equivalent and substitute parts for ongoing design requirements and production continuity. The MMBT3904T operates at a transition frequency of 300MHz with a maximum power dissipation of 250mW in the SC-89-3 package configuration.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Collector-Emitter Breakdown Voltage (Max)	40	V
Collector Current (Max)	200	mA
Power Dissipation (Max)	250	mW
Transition Frequency	300	MHz
DC Current Gain (hFE Min)	100	@ 10mA, 1V
Vce Saturation (Max)	300	mV @ 5mA, 50mA
Operating Temperature (Max)	150	°C
Mounting Type	Surface Mount	—
Package	SC-89-3	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the MMBT3904T is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

Transistor type must be NPN
Collector-emitter breakdown voltage must be 40V or greater
Maximum collector current must be 200mA or greater
DC current gain (hFE) minimum must be 100 or greater at specified conditions
Vce saturation must not exceed 300mV at specified bias conditions
Transition frequency must be 300MHz or greater

Mechanical Compatibility Criteria:

Surface mount mounting type
Package footprint compatibility with SC-89-3, SOT-23-3, SOT-416, SOT-523, or TO-236AB configurations
Moisture sensitivity level of 1 (Unlimited)

Compliance Criteria:

RoHS3 compliance required
REACH unaffected status

Substitute parts are grouped into three categories: direct equivalents (same base part number with different packaging or manufacturer), similar performance alternatives (matching electrical specifications with different package options), and automotive-grade upgrades (AEC-Q101 qualified variants).

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) V	Power mW	Freq MHz	Package	Status	Automotive
MMBT3904T	onsemi	200	40	250	300	SC-89-3	Obsolete	No
MMBT3904LT1G	onsemi	200	40	300	300	SOT-23-3	Active	No
MMBT3904TT1G	onsemi	200	40	300	300	SOT-416	Active	No
MMBT3904-TP	Micro Commercial Co	200	40	350	300	SOT-23	Active	No
MMBT3904,215	Nexperia USA Inc.	200	40	250	300	TO-236AB	Active	Yes
MMBT3904T-TP	Micro Commercial Co	200	40	150	300	SOT-523	Active	No
PMBS3904,215	Nexperia USA Inc.	100	40	250	180	TO-236AB	Active	Yes
PMBS3904,235	Nexperia USA Inc.	100	40	250	180	TO-236AB	Active	Yes
SST3904T116	Rohm Semiconductor	200	40	350	300	SOT-23-3	Active	No

Engineering Selection Recommendations

Direct Equivalents (Recommended Primary Substitutes):

MMBT3904LT1G (onsemi) and MMBT3904TT1G (onsemi) are direct equivalents sharing the same base part number and electrical specifications. Both are active products with enhanced power ratings (300mW versus 250mW) and extended operating temperature ranges (-55°C to 150°C). MMBT3904LT1G uses SOT-23-3 packaging, while MMBT3904TT1G uses SOT-416 packaging. Selection between these depends on PCB layout requirements and available footprint space.

Automotive-Grade Alternative:

MMBT3904,215 (Nexperia USA Inc.) provides an automotive-qualified option with AEC-Q101 certification. This part maintains identical electrical specifications to the original MMBT3904T and is available in TO-236AB packaging. This option is suitable for applications requiring automotive-grade component qualification.

Alternative Manufacturers:

MMBT3904-TP (Micro Commercial Co) and SST3904T116 (Rohm Semiconductor) offer equivalent electrical performance with increased power dissipation ratings (350mW). Both maintain 200mA collector current and 300MHz transition frequency specifications. These parts are available in SOT-23 and SOT-23-3 packages respectively.

Limited Current Applications:

PMBS3904,215 and PMBS3904,235 (Nexperia USA Inc.) are automotive-qualified alternatives with reduced maximum collector current (100mA) and transition frequency (180MHz). These parts are suitable only for applications where the lower current and frequency specifications are acceptable.

Reduced Power Dissipation Option:

MMBT3904T-TP (Micro Commercial Co) provides a compact SOT-523 package option with reduced power dissipation (150mW). This part is suitable for space-constrained applications where the lower power rating is compatible with circuit requirements.

Frequently Asked Questions (FAQ)

Q: Can MMBT3904LT1G directly replace MMBT3904T in existing designs?

A: MMBT3904LT1G is electrically equivalent and meets or exceeds all electrical specifications of MMBT3904T. However, the package changes from SC-89-3 to SOT-23-3, requiring PCB layout modification. Pin configuration remains compatible (NPN, three-terminal configuration).

Q: What is the difference between MMBT3904,215 and MMBT3904LT1G?

A: MMBT3904,215 is manufactured by Nexperia and carries AEC-Q101 automotive qualification. MMBT3904LT1G is manufactured by onsemi without automotive qualification. Both share identical electrical specifications and TO-236AB/SOT-23-3 package compatibility. Selection depends on automotive qualification requirements.

Q: Why are PMBS3904,215 and PMBS3904,235 listed as substitutes if they have lower current ratings?

A: These parts are listed as similar alternatives for applications where maximum collector current does not exceed 100mA and transition frequency requirements do not exceed 180MHz. They are not suitable for designs requiring the full 200mA current capability of MMBT3904T.

Q: Is the MMBT3904T-TP suitable for high-power applications?

A: No. MMBT3904T-TP has a maximum power dissipation of 150mW, which is 40% lower than the original MMBT3904T (250mW). This part is suitable only for low-power applications where thermal constraints are minimal.

Q: What packaging options are available for direct electrical equivalents?

A: Direct electrical equivalents are available in the following packages: SOT-23-3 (MMBT3904LT1G), SOT-416 (MMBT3904TT1G), SOT-23 (MMBT3904-TP), and TO-236AB (MMBT3904,215). Selection depends on PCB footprint availability and assembly equipment compatibility.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts maintain RoHS3 compliance and REACH unaffected status, matching the environmental compliance profile of the original MMBT3904T.

Q: Which substitute part offers the best thermal performance?

A: MMBT3904-TP and SST3904T116 both offer 350mW maximum power dissipation, providing 40% higher thermal capability than the original MMBT3904T. These parts are suitable for applications with elevated power dissipation requirements.

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