FMMTA64TC PNP Darlington Transistor Equivalent & Substitute Parts

Part Overview

The FMMTA64TC is a PNP Darlington bipolar junction transistor manufactured by Diodes Incorporated, designed for surface mount applications in the SOT-23-3 package. This device is rated for 30 V collector-emitter breakdown voltage and 500 mA maximum collector current, with a maximum power dissipation of 330 mW. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. Substitute parts must maintain electrical compatibility across critical parameters including voltage rating, current capacity, DC current gain, and thermal characteristics while accommodating modern active product availability.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP - Darlington	—
Collector-Emitter Breakdown Voltage (Max)	30	V
Collector Current (Max)	500	mA
Vce Saturation (Max) @ Ib, Ic	1.5 V @ 100 µA, 100 mA	V
DC Current Gain (hFE) (Min) @ Ic, Vce	20000 @ 100 mA, 5 V	—
Power Dissipation (Max)	330	mW
Transition Frequency	125	MHz
Operating Temperature Range	-55 to 150	°C
Package / Case	SOT-23-3 (TO-236-3, SC-59)	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the FMMTA64TC is determined by strict electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

Transistor type must be PNP - Darlington configuration
Collector-emitter breakdown voltage must be ≥ 30 V
Maximum collector current must be ≥ 500 mA
DC current gain (hFE) must be ≥ 20000 @ 100 mA, 5 V
Vce saturation characteristics must support the specified operating point
Collector cutoff current (ICBO) must be ≤ 100 nA

Mechanical Compatibility Criteria:

Package must be SOT-23-3 (TO-236-3, SC-59) or equivalent surface mount variant
Mounting type must be surface mount
Moisture sensitivity level must be ≤ 1 (Unlimited)

Environmental & Compliance Criteria:

RoHS3 compliance required
Operating temperature range must encompass -55°C to 150°C or higher maximum

Substitute parts are grouped into two categories: Direct Electrical Equivalents (matching all electrical parameters within specification) and Functional Equivalents (meeting or exceeding electrical requirements with minor parameter variations). Parts with reduced current capacity (300 mA) or lower maximum power dissipation are listed as functional equivalents suitable for applications not requiring full 500 mA operation.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) V	Vce Sat @ Ib, Ic	hFE (Min) @ Ic, Vce	Power (Max) mW	Freq MHz	Temp Range °C	Package	Status
FMMTA64TC	Diodes Incorporated	500	30	1.5V @ 100µA, 100mA	20000 @ 100mA, 5V	330	125	-55 to 150	SOT-23-3	Obsolete
MMBTA64-7-F	Diodes Incorporated	500	30	1.5V @ 100µA, 100mA	20000 @ 100mA, 5V	300	125	-55 to 150	SOT-23-3	Active
BCV26,215	Nexperia USA Inc.	500	30	1V @ 100µA, 100mA	20000 @ 100mA, 5V	250	220	-55 to 150	TO-236AB	Active
MMBTA64LT1G	onsemi	500	30	1.5V @ 100µA, 100mA	20000 @ 100mA, 5V	225	125	-55 to 150	SOT-23-3	Active
MMBTA64LT3G	onsemi	500	30	1.5V @ 100µA, 100mA	20000 @ 100mA, 5V	225	125	-55 to 150	SOT-23-3	Active
PMBTA64,215	Nexperia USA Inc.	500	30	1.5V @ 100µA, 100mA	20000 @ 100mA, 5V	250	125	-55 to 150	TO-236AB	Active
SMMBTA64LT1G	onsemi	500	30	1.5V @ 100µA, 100mA	20000 @ 100mA, 5V	225	125	-55 to 150	SOT-23-3	Active
2SB852KT146B	Rohm Semiconductor	300	32	1.5V @ 400µA, 200mA	5000 @ 100mA, 5V	200	200	-55 to 150	SMT3	Active
BCV26	onsemi	1200	30	1V @ 100µA, 100mA	20000 @ 100mA, 5V	350	220	-55 to 150	SOT-23-3	Active
BCV26,235	NXP USA Inc.	500	30	1V @ 100µA, 100mA	20000 @ 100mA, 5V	250	220	-55 to 150	SOT-23	Active
BCV26E6327HTSA1	Infineon Technologies	500	30	1V @ 100µA, 100mA	20000 @ 100mA, 5V	360	200	-55 to 150	PG-SOT23	Obsolete

Engineering Selection Recommendations

Primary Recommendation: MMBTA64-7-F (Diodes Incorporated)

MMBTA64-7-F is the direct successor to FMMTA64TC from the same manufacturer. It maintains identical electrical specifications (500 mA, 30 V, 20000 hFE) and package format (SOT-23-3), with active product status and AEC-Q101 automotive qualification. Power dissipation is reduced to 300 mW, which is acceptable for applications not requiring the full 330 mW specification. This part offers the highest compatibility with existing designs and supply chain continuity.

Secondary Recommendations: MMBTA64LT1G, MMBTA64LT3G, SMMBTA64LT1G (onsemi)

These onsemi variants provide full electrical equivalence with 500 mA collector current, 30 V breakdown voltage, and 20000 hFE gain. All three parts are active products with identical SOT-23-3 packaging and -55°C to 150°C operating range. Power dissipation is 225 mW. MMBTA64LT1G and SMMBTA64LT1G offer the highest inventory availability (23,100 and 35,100 units respectively). These parts are suitable for direct substitution in applications where the reduced power rating is acceptable.

Automotive-Grade Alternatives: PMBTA64,215 (Nexperia USA Inc.), BCV26,235 (NXP USA Inc.)

Both parts carry AEC-Q101 automotive qualification and maintain 500 mA collector current with 30 V breakdown voltage. PMBTA64,215 matches the original 125 MHz transition frequency, while BCV26,235 operates at 220 MHz. Both use TO-236AB packaging (mechanically compatible with SOT-23-3) and are active products. These options are preferred for automotive and industrial applications requiring formal qualification documentation.

Higher Current Capability: BCV26 (onsemi)

BCV26 provides 1.2 A maximum collector current with 30 V breakdown voltage and 220 MHz transition frequency. This part is suitable for applications requiring higher current capacity than the original 500 mA specification. It maintains 20000 hFE gain and operates across -55°C to 150°C. Extensive inventory availability (185,100 units) supports high-volume production.

Functional Equivalent with Reduced Current: 2SB852KT146B (Rohm Semiconductor)

2SB852KT146B is a functional equivalent suitable for applications not requiring full 500 mA operation. It provides 300 mA maximum collector current, 32 V breakdown voltage (exceeding the 30 V requirement), and 200 MHz transition frequency. DC current gain is reduced to 5000 hFE, which may limit applicability in high-impedance circuits. This part is recommended only when current requirements are confirmed below 300 mA.

Obsolete Parts to Avoid: BCV26E6327HTSA1 (Infineon Technologies)

BCV26E6327HTSA1 is classified as obsolete and should not be selected for new designs despite meeting electrical specifications. Limited inventory (1,090 units) and discontinued status create supply chain risk.

Frequently Asked Questions (FAQ)

Q: Can MMBTA64-7-F directly replace FMMTA64TC without circuit modification?

A: Yes. MMBTA64-7-F is electrically equivalent to FMMTA64TC across all critical parameters: 500 mA collector current, 30 V breakdown voltage, 20000 hFE minimum gain, and identical SOT-23-3 packaging. The 30 mW reduction in maximum power dissipation (from 330 mW to 300 mW) does not affect functionality in standard applications. No circuit changes are required.

Q: What is the difference between MMBTA64LT1G and MMBTA64LT3G?

A: Both parts are electrically identical with 500 mA collector current, 30 V breakdown voltage, 20000 hFE gain, and 225 mW power dissipation. The suffix designations (LT1G vs. LT3G) indicate different manufacturing date codes or tape reel configurations from onsemi. Electrical performance and package format are identical. Selection between these parts is based on inventory availability and supply chain preference.

Q: Is BCV26 a suitable substitute if my application requires higher current?

A: Yes, if your circuit design permits. BCV26 provides 1.2 A maximum collector current compared to the original 500 mA specification, with identical 30 V breakdown voltage and 20000 hFE gain. The higher current rating makes it suitable for applications requiring current capacity beyond 500 mA. However, verify that your PCB layout and thermal management accommodate the potentially higher power dissipation (350 mW maximum).

Q: Why do some substitute parts have lower power dissipation ratings?

A: Power dissipation ratings reflect the maximum thermal capability of the specific device variant and package implementation. MMBTA64LT1G, MMBTA64LT3G, and SMMBTA64LT1G are rated at 225 mW compared to the original 330 mW. This reduction does not affect electrical functionality; it indicates more conservative thermal design margins. These parts are suitable for applications where actual power dissipation remains below 225 mW.

Q: Can I use 2SB852KT146B as a direct replacement?

A: 2SB852KT146B is a functional equivalent only for applications where collector current does not exceed 300 mA. It provides lower DC current gain (5000 hFE vs. 20000 hFE), which may affect circuit performance in high-impedance or low-base-current applications. Verify that your circuit operates within the 300 mA current limit and that the reduced gain does not compromise circuit function before substitution.

Q: What is the difference between TO-236AB and SOT-23-3 packaging?

A: TO-236AB and SOT-23-3 are mechanically equivalent package designations for the same three-lead surface mount form factor. Both refer to the same physical dimensions and pin configuration. Parts specified as TO-236AB (such as PMBTA64,215 and BCV26,235) are directly compatible with PCB layouts designed for SOT-23-3 components. No package adapter or layout modification is required.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed in this reference are RoHS3 compliant and carry moisture sensitivity level 1 (unlimited). They meet the same environmental and regulatory requirements as the original FMMTA64TC.

Q: Which substitute part offers the best supply chain continuity?

A: SMMBTA64LT1G (onsemi) offers the highest inventory availability at 35,100 units in stock, followed by MMBTA64LT1G (23,100 units) and BCV26 (185,100 units). For immediate production needs, SMMBTA64LT1G provides the most secure supply position. For long-term availability, BCV26 from onsemi represents the most established product line with extensive market adoption.

Q: Do automotive-qualified parts (AEC-Q101) perform differently than standard parts?

A: Automotive-qualified parts (MMBTA64-7-F, PMBTA64,215, BCV26,235) undergo additional qualification testing and documentation per AEC-Q101 standards. Electrical performance is equivalent to non-qualified variants; the qualification designation indicates compliance with automotive industry reliability and traceability requirements. Selection of AEC-Q101 parts is required for automotive applications; standard parts are acceptable for consumer and industrial applications.

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