KST63MTF Equivalent & Substitute Parts

Part Overview

The KST63MTF is a PNP Darlington bipolar junction transistor manufactured by onsemi, designed for surface mount applications in the SOT-23-3 package. This device operates at 30 V collector-emitter breakdown voltage with a maximum collector current of 500 mA and delivers 350 mW power dissipation. The KST63MTF is classified as obsolete, necessitating identification of active equivalent and substitute components for new designs and production continuity. Substitute parts must maintain electrical compatibility across critical parameters including voltage ratings, current capacity, and thermal characteristics while accommodating modern supply chain availability.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP - Darlington	—
Collector Current (Max)	500	mA
Collector-Emitter Breakdown Voltage (Max)	30	V
Vce Saturation (Max)	1.5	V @ 100µA, 100mA
DC Current Gain (hFE Min)	10000	@ 100mA, 5V
Power Dissipation (Max)	350	mW
Transition Frequency	125	MHz
Package Type	SOT-23-3 (TO-236-3, SC-59)	—
Mounting Type	Surface Mount	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the KST63MTF is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Transistor topology: PNP Darlington configuration
Collector current rating: 500 mA minimum
Collector-emitter breakdown voltage: 30 V minimum
Package compatibility: SOT-23-3 / TO-236-3 surface mount
Saturation voltage: 1.5 V maximum at specified bias conditions
Moisture sensitivity: MSL 1 (Unlimited)

Secondary Compatibility Factors:

DC current gain (hFE): Minimum 5000 @ 100mA, 5V (lower than KST63MTF but acceptable for most applications)
Power dissipation: 225 mW to 360 mW range
Transition frequency: 125 MHz to 220 MHz
Operating temperature range: -55°C to 150°C (TJ)

Parts are grouped into direct equivalents (matching all primary criteria with active product status) and similar alternatives (meeting electrical requirements with minor parameter variations or different manufacturers).

Parameter Comparison

Part Number	Manufacturer	Status	Ic (Max) mA	Vce(br) V	Vce Sat V	hFE Min	Power mW	fT MHz	Package
KST63MTF	onsemi	Obsolete	500	30	1.5	10000	350	125	SOT-23-3
MMBTA63LT1G	onsemi	Active	500	30	1.5	5000	225	125	SOT-23-3
MMBTA64LT1G	onsemi	Active	500	30	1.5	20000	225	125	SOT-23-3
MMBTA64LT3G	onsemi	Active	500	30	1.5	20000	225	125	SOT-23-3
MMBTA63-7-F	Diodes Incorporated	Active	500	30	1.5	10000	300	125	SOT-23-3
MMBTA64-7-F	Diodes Incorporated	Active	500	500	1.5	20000	300	125	SOT-23-3
PMBTA64,215	Nexperia USA Inc.	Active	500	30	1.5	20000	250	125	TO-236AB
BCV26,215	Nexperia USA Inc.	Active	500	30	1.0	20000	250	220	TO-236AB
BCV26,235	NXP USA Inc.	Active	500	30	1.0	20000	250	220	SOT-23
BCV26E6327HTSA1	Infineon Technologies	Obsolete	500	30	1.0	20000	360	200	PG-SOT23
2SB852KT146B	Rohm Semiconductor	Active	300	32	1.5	5000	200	200	SMT3

Engineering Selection Recommendations

Direct Equivalents (Recommended Primary Choices):

MMBTA63LT1G and MMBTA64LT1G from onsemi represent the most direct functional equivalents to the KST63MTF. Both devices maintain identical voltage and current ratings, matching saturation voltage specifications, and operate within the same frequency range. MMBTA63LT1G provides hFE of 5000 (lower than KST63MTF) while MMBTA64LT1G delivers hFE of 20000 (higher). Both are active products with RoHS3 compliance and unlimited moisture sensitivity rating. MMBTA63LT1G is available in Cut Tape and Digi-Reel packaging with 152,660 units in stock, while MMBTA64LT1G is supplied in Tape & Reel format with 23,100 units available.

Automotive-Qualified Alternatives:

MMBTA63-7-F and MMBTA64-7-F from Diodes Incorporated are AEC-Q101 qualified automotive-grade devices. Both maintain 500 mA collector current and 30 V breakdown voltage with 1.5 V saturation voltage. MMBTA63-7-F matches the KST63MTF hFE specification at 10000, while MMBTA64-7-F provides 20000. Power dissipation is rated at 300 mW, exceeding the KST63MTF specification. MMBTA64-7-F has 34,975 units in stock.

Nexperia Alternatives:

PMBTA64,215 from Nexperia USA Inc. meets all primary electrical specifications with 500 mA, 30 V, and 1.5 V saturation voltage. This part carries AEC-Q101 automotive qualification and RoHS3 compliance. The TO-236AB package is mechanically compatible with SOT-23-3 footprints. PMBTA64,215 is active with 4,015 units available.

BCV26,215 and BCV26,235 from Nexperia/NXP provide enhanced transition frequency at 220 MHz with reduced saturation voltage of 1.0 V. Both maintain 500 mA and 30 V ratings with AEC-Q101 qualification. BCV26,215 is supplied in Tape & Reel (3,718 units), while BCV26,235 is available in bulk packaging (10,920 units).

Limited Compatibility Alternative:

2SB852KT146B from Rohm Semiconductor is a partial substitute with reduced collector current (300 mA maximum) and higher breakdown voltage (32 V). This device is suitable only for applications where the 300 mA current limit is acceptable. The SMT3 package differs from SOT-23-3, requiring PCB layout verification. This part is active with 24,100 units in stock.

Obsolete Parts to Avoid:

BCV26E6327HTSA1 from Infineon Technologies is classified as obsolete and should not be selected for new designs despite meeting electrical specifications.

Frequently Asked Questions (FAQ)

Q: Can MMBTA63LT1G directly replace KST63MTF in all applications?

A: MMBTA63LT1G is electrically compatible for applications where the reduced DC current gain (5000 vs. 10000) does not impact circuit performance. The lower hFE may require increased base drive current in some switching applications. Verify base current requirements in your specific circuit design.

Q: What is the difference between MMBTA64LT1G and MMBTA64LT3G?

A: Both parts are functionally identical with 500 mA collector current, 30 V breakdown voltage, and 20000 hFE minimum. The primary difference is packaging designation and supplier reel configuration. MMBTA64LT1G has 23,100 units in stock, while MMBTA64LT3G has 785 units available.

Q: Are Nexperia BCV26 parts pin-compatible with KST63MTF?

A: Yes. BCV26,215 and BCV26,235 maintain the same SOT-23-3 / TO-236AB pinout as KST63MTF. The TO-236AB package designation indicates mechanical and electrical compatibility with SOT-23-3 footprints.

Q: Why does 2SB852KT146B have lower collector current (300 mA vs. 500 mA)?

A: 2SB852KT146B is a different device variant optimized for lower current applications. It is not a true equivalent and should only be used when circuit requirements permit 300 mA maximum collector current operation.

Q: What is the significance of AEC-Q101 qualification on MMBTA63-7-F and MMBTA64-7-F?

A: AEC-Q101 qualification indicates these devices meet automotive industry reliability and quality standards. These parts are suitable for automotive and industrial applications requiring enhanced qualification documentation.

Q: Can I use BCV26E6327HTSA1 as a substitute?

A: BCV26E6327HTSA1 is classified as obsolete and is not recommended for new designs. Although it meets electrical specifications, obsolete parts present supply chain risk and should be avoided in favor of active alternatives.

Q: What packaging options are available for KST63MTF substitutes?

A: Substitute parts are supplied in multiple packaging formats: Cut Tape (CT) & Digi-Reel, Tape & Reel (TR), and Bulk. SOT-23-3 and TO-236AB packages are mechanically interchangeable. Verify your assembly equipment compatibility with the selected packaging format.

Q: How do saturation voltage differences affect circuit performance?

A: KST63MTF specifies 1.5 V saturation voltage, while BCV26 variants specify 1.0 V. Lower saturation voltage reduces power dissipation in saturated switching applications. This difference is typically negligible in most circuit designs but should be verified for high-current or thermally constrained applications.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All active substitute parts listed carry RoHS3 compliance certification. Obsolete parts (KST63MTF and BCV26E6327HTSA1) have REACH Unaffected status.

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