MMBT100A Equivalent & Substitute Parts

Part Overview

The MMBT100A is an NPN bipolar junction transistor manufactured by onsemi, designed for general-purpose switching and amplification applications. This device features a 45 V collector-emitter breakdown voltage, 500 mA maximum collector current, and 350 mW power dissipation in a surface-mount SOT-23-3 package. The MMBT100A is classified as obsolete; however, equivalent and substitute parts remain available from multiple manufacturers. Identifying suitable alternatives ensures design continuity and maintains supply chain flexibility for applications requiring NPN transistor functionality within the specified electrical and mechanical parameters.

Key Parameters

Parameter	MMBT100A Value	Unit
Transistor Type	NPN	—
Collector-Emitter Breakdown Voltage (Max)	45	V
Collector Current (Max)	500	mA
Power Dissipation (Max)	350	mW
Transition Frequency	250	MHz
Operating Temperature Range	−55 to 150	°C
Package Type	SOT-23-3 (TO-236-3, SC-59)	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitute parts for the MMBT100A are classified based on electrical parameter compatibility within the following criteria:

Primary Substitution Criteria:

Transistor type must be NPN
Collector-emitter breakdown voltage must be ≥45 V
Maximum collector current must be ≥500 mA
Package must be SOT-23-3 or equivalent surface-mount variant (TO-236-3, SC-59, SMT3)
Operating temperature range must encompass −55°C to 150°C or higher
Mounting type must be surface mount

Grouping Logic:

Group 1 – Direct Equivalents (Identical Electrical Ratings): Parts meeting all primary criteria with collector current of 500 mA, breakdown voltage of 45 V, and power dissipation of 300–350 mW.

Group 2 – Enhanced Performance Substitutes (Higher Current or Voltage): Parts with collector current ≥500 mA and breakdown voltage ≥45 V, suitable for applications where the MMBT100A is specified but higher ratings provide design margin.

Group 3 – Reduced Current Substitutes (Lower Current Rating): Parts with collector current <500 mA but meeting voltage and package requirements; applicable only when circuit design permits reduced current handling.

Group 4 – Cross-Manufacturer Alternatives: Parts from manufacturers other than onsemi meeting equivalent electrical and mechanical specifications.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) (Max) V	Power (Max) mW	fT MHz	Package	Status
MMBT100A	onsemi	500	45	350	250	SOT-23-3	Obsolete
BCX19LT1G	onsemi	500	45	300	—	SOT-23-3	Active
MMBT100	onsemi	500	45	350	250	SOT-23-3	Active
MMBT6429LT1G	onsemi	200	45	225	700	SOT-23-3	Active
NSVBC817-16LT1G	onsemi	500	45	225	100	SOT-23-3	Active
SMMBT4401LT1G	onsemi	600	40	300	250	SOT-23-3	Active
2SD1484KT146Q	Rohm Semiconductor	500	50	200	250	SMT3	Active
2SD1484KT146R	Rohm Semiconductor	500	50	200	250	SMT3	Active
BC817-16,215	Nexperia USA Inc.	500	45	250	100	TO-236AB	Active
BC817-25 RFG	Taiwan Semiconductor Corporation	500	45	300	100	SOT-23	Active
BC817-25,235	Nexperia USA Inc.	500	45	250	100	TO-236AB	Active

Engineering Selection Recommendations

Recommended Primary Substitute: MMBT100

The MMBT100 is the active-status equivalent of the obsolete MMBT100A. Both parts are manufactured by onsemi and share identical electrical specifications: 500 mA collector current, 45 V breakdown voltage, 350 mW power dissipation, 250 MHz transition frequency, and SOT-23-3 packaging. The MMBT100 carries RoHS3 compliance and is in active production with substantial inventory availability (65,400 units). This part provides direct functional replacement without circuit redesign.

Secondary Substitutes (onsemi Alternatives):

BCX19LT1G meets all primary substitution criteria with 500 mA collector current and 45 V breakdown voltage in SOT-23-3 packaging. Power dissipation is 300 mW (50 mW lower than MMBT100A), and transition frequency is not specified. This part is active and RoHS3 compliant.

NSVBC817-16LT1G provides 500 mA collector current and 45 V breakdown voltage in SOT-23-3 packaging with extended operating temperature range (−65°C to 150°C). Transition frequency is 100 MHz (lower than MMBT100A), and power dissipation is 225 mW. This part is active and RoHS3 compliant.

Cross-Manufacturer Alternatives:

BC817-16,215 (Nexperia USA Inc.) and BC817-25,235 (Nexperia USA Inc.) both provide 500 mA collector current and 45 V breakdown voltage in TO-236AB packaging. Both are active, RoHS3 compliant, and carry AEC-Q101 automotive qualification. Transition frequency is 100 MHz. These parts are suitable for applications where automotive-grade components are required.

BC817-25 RFG (Taiwan Semiconductor Corporation) offers 500 mA collector current and 45 V breakdown voltage in SOT-23 packaging. This part is active and RoHS3 compliant with 100 MHz transition frequency.

Substitutes with Parameter Deviations:

MMBT6429LT1G has reduced collector current (200 mA maximum) but offers higher transition frequency (700 MHz). This part is suitable only for applications where current requirements do not exceed 200 mA.

SMMBT4401LT1G provides 600 mA collector current but has reduced breakdown voltage (40 V). This part is suitable only for applications where the 40 V rating is acceptable.

2SD1484KT146Q and 2SD1484KT146R (Rohm Semiconductor) provide 500 mA collector current and 50 V breakdown voltage (higher than MMBT100A) in SMT3 packaging. Power dissipation is 200 mW. Both are active and RoHS3 compliant. These parts are suitable for applications requiring enhanced voltage margin.

Frequently Asked Questions (FAQ)

Q: Can MMBT100 directly replace MMBT100A without circuit modification?

A: Yes. The MMBT100 is the active-production equivalent of the obsolete MMBT100A. Both parts share identical electrical specifications (500 mA, 45 V, 350 mW, 250 MHz) and SOT-23-3 packaging. Direct substitution is supported without circuit redesign.

Q: What is the primary difference between MMBT100A and BCX19LT1G?

A: Both parts provide 500 mA collector current and 45 V breakdown voltage in SOT-23-3 packaging. BCX19LT1G has 300 mW power dissipation (50 mW lower) and does not specify transition frequency. MMBT100A specifies 350 mW and 250 MHz. BCX19LT1G is suitable for applications where the lower power rating is acceptable.

Q: Are BC817 variants compatible with MMBT100A?

A: BC817 variants (BC817-16,215 and BC817-25,235 from Nexperia; BC817-25 RFG from Taiwan Semiconductor Corporation) provide 500 mA collector current and 45 V breakdown voltage in SOT-23 or TO-236AB packaging. Transition frequency is 100 MHz (lower than MMBT100A's 250 MHz). These parts are compatible for applications where 100 MHz bandwidth is sufficient. Nexperia variants carry AEC-Q101 automotive qualification.

Q: Can MMBT6429LT1G replace MMBT100A?

A: MMBT6429LT1G has reduced collector current (200 mA maximum) compared to MMBT100A (500 mA). This part is suitable only for applications where circuit design permits operation at 200 mA or lower. Higher transition frequency (700 MHz) does not compensate for reduced current capability in applications requiring 500 mA.

Q: What is the significance of SMT3 packaging in 2SD1484 variants?

A: SMT3 is a surface-mount package equivalent to SOT-23-3 and TO-236-3. The 2SD1484KT146Q and 2SD1484KT146R from Rohm Semiconductor are mechanically compatible with MMBT100A footprints. Both provide 500 mA collector current and 50 V breakdown voltage (5 V higher than MMBT100A), offering enhanced voltage margin in designs where this rating is beneficial.

Q: Are there temperature range differences between substitute parts?

A: MMBT100A specifies −55°C to 150°C operating range. NSVBC817-16LT1G extends this to −65°C to 150°C. BC817-16,215 and BC817-25,235 specify 150°C maximum (lower bound not specified). 2SD1484 variants specify 150°C maximum. For applications requiring full −55°C to 150°C range, MMBT100, BCX19LT1G, and NSVBC817-16LT1G are preferred.

Q: What compliance certifications apply to substitute parts?

A: All listed substitute parts are RoHS3 compliant. BC817-16,215 and BC817-25,235 (Nexperia) carry AEC-Q101 automotive qualification. All parts are REACH unaffected and classified as EAR99 for export control purposes.

Q: Can SMMBT4401LT1G replace MMBT100A?

A: SMMBT4401LT1G provides 600 mA collector current (higher than MMBT100A) but has reduced breakdown voltage (40 V versus 45 V). This part is suitable only for applications where 40 V breakdown voltage is acceptable. The higher current capability does not offset the voltage reduction in designs requiring 45 V rating.

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