STPSA92-AP Equivalent & Substitute Parts

Part Overview

The STPSA92-AP is a PNP bipolar junction transistor manufactured by STMicroelectronics, designed for small-signal switching and amplification applications. This device features a maximum collector current of 500 mA, collector-emitter breakdown voltage of 300 V, and maximum power dissipation of 625 mW in a Through Hole TO-92AP package.

The STPSA92-AP is classified as an obsolete product. Identification of equivalent and substitute parts is necessary to support ongoing maintenance, repair, and redesign of legacy systems utilizing this component. Substitute parts must maintain electrical and mechanical compatibility within the specified parameter ranges.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) (Max)	500	mA
Voltage - Collector Emitter Breakdown (Max)	300	V
Vce Saturation (Max) @ Ib, Ic	500mV @ 2mA, 20mA	—
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 30mA, 10V	—
Power - Max	625	mW
Frequency - Transition	50	MHz
Operating Temperature (TJ)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3 (TO-226AA)	—

Substitute Part Grouping Explanation

Substitution of the STPSA92-AP is determined by equivalence across the following critical electrical and mechanical parameters:

Electrical Equivalence Criteria:

Transistor type must be PNP
Maximum collector current (Ic) must be ≥ 500 mA
Collector-emitter breakdown voltage (VCEO) must be ≥ 300 V
Maximum power dissipation must be ≥ 625 mW
Transition frequency must be ≥ 50 MHz
Operating temperature range must support 150°C (TJ)
Vce saturation characteristics must be compatible at specified bias conditions

Mechanical Equivalence Criteria:

Mounting type must be Through Hole
Package must be TO-92-3 or equivalent TO-226-3 form factor
Lead configuration must support direct board-level substitution

The KSP92BU manufactured by Fairchild Semiconductor meets all specified electrical and mechanical parameters and is classified as an active product, providing long-term availability for legacy system support.

Parameter Comparison

Parameter	STPSA92-AP (STMicroelectronics)	KSP92BU (Fairchild Semiconductor)	Match Status
Transistor Type	PNP	PNP	Equivalent
Current - Collector (Ic) (Max)	500 mA	500 mA	Equivalent
Voltage - Collector Emitter Breakdown (Max)	300 V	300 V	Equivalent
Vce Saturation (Max) @ Ib, Ic	500mV @ 2mA, 20mA	500mV @ 2mA, 20mA	Equivalent
Current - Collector Cutoff (Max)	100 nA	250 nA	Compatible
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 30mA, 10V	25 @ 30mA, 10V	Compatible
Power - Max	625 mW	625 mW	Equivalent
Frequency - Transition	50 MHz	50 MHz	Equivalent
Operating Temperature (TJ)	150°C	150°C	Equivalent
Mounting Type	Through Hole	Through Hole	Equivalent
Package / Case	TO-226-3, TO-92-3	TO-226-3, TO-92-3	Equivalent
Product Status	Obsolete	Active	Substitute is Active

Engineering Selection Recommendations

Primary Substitute: KSP92BU (Fairchild Semiconductor)

The KSP92BU is the recommended substitute for the obsolete STPSA92-AP. This selection is based on the following engineering factors:

Electrical Compatibility: The KSP92BU maintains all critical electrical parameters at or above the STPSA92-AP specifications. Maximum collector current, breakdown voltage, power dissipation, and transition frequency are identical. Vce saturation characteristics are equivalent. The DC current gain (hFE) of the KSP92BU is lower (25 vs. 40 minimum), which represents a conservative design margin and does not preclude substitution in applications where the original part was specified.

Mechanical Compatibility: Both devices utilize identical Through Hole mounting technology and TO-92-3 package form factors, enabling direct board-level substitution without layout modification.

Product Status and Availability: The KSP92BU is classified as an active product with substantial inventory availability (105,400 pieces), ensuring long-term supply continuity for legacy system support and new production runs.

Compliance: Both devices are RoHS3 compliant and carry identical ECCN and HTSUS classifications, supporting regulatory and procurement requirements.

Frequently Asked Questions (FAQ)

Q: Can the KSP92BU be used as a direct replacement for the STPSA92-AP without circuit modification?

A: Yes. The KSP92BU meets or exceeds all electrical specifications of the STPSA92-AP and shares identical package and mounting characteristics. Direct substitution is supported at the board level without circuit redesign.

Q: What is the significance of the difference in DC current gain (hFE) between the two devices?

A: The STPSA92-AP specifies a minimum hFE of 40 at 30 mA collector current and 10 V collector-emitter voltage. The KSP92BU specifies a minimum hFE of 25 under identical conditions. This difference indicates that the KSP92BU exhibits lower current amplification. In applications where base drive current is calculated based on the original part's hFE, the KSP92BU will require proportionally higher base current to achieve the same collector current. Circuit designs that account for hFE variation or employ feedback mechanisms will accommodate this difference without performance degradation.

Q: Are there package compatibility concerns when substituting the KSP92BU for the STPSA92-AP?

A: No. Both devices are supplied in TO-92-3 (TO-226AA) Through Hole packages with formed leads. Pin assignments and lead spacing are identical, supporting direct board-level substitution without mechanical modification.

Q: What is the difference between the STPSA92-AP supplier device package designation (TO-92AP) and the KSP92BU designation (TO-92-3)?

A: The TO-92AP designation indicates a specific STMicroelectronics package variant with formed leads. The TO-92-3 designation is the industry-standard nomenclature for the same physical package form factor. Both designations refer to the same mechanical and electrical package specification. The KSP92BU is compatible with applications designed for the STPSA92-AP.

Q: Why is the STPSA92-AP classified as obsolete?

A: The STPSA92-AP is no longer manufactured by STMicroelectronics. Obsolescence typically results from product line consolidation, technology transition, or market demand shifts. The KSP92BU, manufactured by Fairchild Semiconductor and classified as an active product, provides functional and electrical equivalence for legacy system support.

Q: What is the collector cutoff current (ICBO) difference between the two devices, and does it affect substitution?

A: The STPSA92-AP specifies a maximum ICBO of 100 nA, while the KSP92BU specifies 250 nA. Collector cutoff current represents leakage current when the transistor is in the off state. The higher leakage of the KSP92BU is within acceptable limits for small-signal switching applications and does not preclude substitution. Applications sensitive to leakage current should evaluate circuit-level impact through simulation or testing.

Q: Are there compliance or regulatory differences between the STPSA92-AP and KSP92BU?

A: Both devices share identical ECCN (EAR99) and HTSUS (8541.21.0095) classifications. The STPSA92-AP is RoHS3 compliant. Compliance documentation for the KSP92BU should be verified through the manufacturer or authorized distributor to confirm equivalent regulatory status for your specific application and jurisdiction.

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