KST93MTF Equivalent & Substitute Parts

Part Overview

The KST93MTF is a Surface Mount PNP Bipolar Junction Transistor manufactured by onsemi, rated for 200V collector-emitter breakdown voltage and 500mA maximum collector current. This device is packaged in SOT-23-3 and is classified as obsolete. Due to its obsolete product status, equivalent substitute components are necessary for new designs and ongoing production requirements where inventory depletion occurs.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) (Max)	500	mA
Voltage - Collector Emitter Breakdown (Max)	200	V
Power - Max	250	mW
Frequency - Transition	50	MHz
Operating Temperature Range	-55 to 150	°C
Package / Case	SOT-23-3	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the KST93MTF is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

Transistor polarity must be PNP
Voltage - Collector Emitter Breakdown rating must be equal to or greater than 200V
Package and mounting type must be SOT-23-3 Surface Mount
Operating temperature range must encompass -55°C to 150°C

Functional Compatibility Criteria:

Current rating and power dissipation capacity must support the application requirements
Transition frequency must be adequate for the intended switching frequency

The FMMT596TA from Diodes Incorporated meets the mandatory electrical and mechanical substitution criteria. While this substitute exhibits different maximum collector current (300mA versus 500mA) and power rating (500mW versus 250mW), it maintains voltage compatibility, package equivalence, and temperature range alignment.

Parameter Comparison

Parameter	KST93MTF (onsemi)	FMMT596TA (Diodes Inc.)	Unit
Transistor Type	PNP	PNP	—
Current - Collector (Ic) (Max)	500	300	mA
Voltage - Collector Emitter Breakdown (Max)	200	200	V
Vce Saturation (Max)	500mV @ 2mA, 20mA	350mV @ 25mA, 250mA	V @ Ib, Ic
Current - Collector Cutoff (Max)	250	100	nA
DC Current Gain (hFE) (Min)	25 @ 30mA, 10V	85 @ 250mA, 10V	@ Ic, Vce
Power - Max	250	500	mW
Frequency - Transition	50	150	MHz
Operating Temperature Range	-55 to 150	-55 to 150	°C
Package / Case	SOT-23-3	SOT-23-3	—
Mounting Type	Surface Mount	Surface Mount	—
Product Status	Obsolete	Active	—

Engineering Selection Recommendations

KST93MTF (onsemi): This component is classified as obsolete and should not be selected for new designs. Existing inventory is available (149,400 pcs), but long-term supply cannot be assured.

FMMT596TA (Diodes Incorporated): This component is classified as active product status and is RoHS3 compliant. It is suitable for new designs and ongoing production. The FMMT596TA provides superior electrical performance characteristics including higher DC current gain (85 versus 25), higher transition frequency (150MHz versus 50MHz), and greater power dissipation capability (500mW versus 250mW). The reduced maximum collector current (300mA versus 500mA) must be evaluated against application requirements.

Both components share identical voltage ratings (200V), operating temperature range (-55°C to 150°C), and package configuration (SOT-23-3 Surface Mount). Both maintain REACH Unaffected status and EAR99 ECCN classification.

Frequently Asked Questions (FAQ)

Q: Can FMMT596TA directly replace KST93MTF in all applications?

A: Direct replacement is possible only when the application collector current requirement does not exceed 300mA. The FMMT596TA maximum collector current rating is 300mA compared to the KST93MTF rating of 500mA. Applications requiring sustained collector currents between 300mA and 500mA require circuit redesign or alternative component selection.

Q: Are the SOT-23-3 packages physically identical?

A: Both components use SOT-23-3 package configuration (also designated TO-236-3 or SC-59). Physical dimensions and PCB footprints are equivalent, enabling direct board-level substitution without layout modification.

Q: What is the significance of the higher DC current gain in FMMT596TA?

A: The FMMT596TA exhibits minimum DC current gain (hFE) of 85 at 250mA and 10V, compared to KST93MTF minimum hFE of 25 at 30mA and 10V. Higher current gain reduces base drive requirements and improves switching efficiency in saturation-mode applications.

Q: Does the higher transition frequency of FMMT596TA affect compatibility?

A: The FMMT596TA transition frequency of 150MHz exceeds the KST93MTF specification of 50MHz. Higher transition frequency enables faster switching operation and is backward compatible with applications designed for lower frequency operation.

Q: What is the impact of different Vce saturation specifications?

A: FMMT596TA exhibits lower saturation voltage (350mV at 25mA, 250mA) compared to KST93MTF (500mV at 2mA, 20mA). Lower saturation voltage reduces power dissipation in saturated switching applications and improves efficiency.

Q: Are there moisture sensitivity or compliance differences?

A: Both components carry MSL Level 1 (Unlimited) moisture sensitivity rating. Both maintain REACH Unaffected status. FMMT596TA includes RoHS3 compliance certification, while KST93MTF compliance information is not provided in the available data.

Q: What inventory considerations apply to these components?

A: KST93MTF inventory is substantial (149,400 pcs) but the obsolete status indicates no future production. FMMT596TA is active product with current inventory of 1,846 pcs and ongoing manufacturing availability.

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