2SB1122S-TD-E Equivalent & Substitute Parts

Part Overview

The 2SB1122S-TD-E is a PNP bipolar junction transistor manufactured by onsemi, rated for 50 V collector-emitter breakdown voltage and 1 A maximum collector current. This device is packaged in TO-243AA (PCP) surface mount configuration with 500 mW power dissipation capability and 150 MHz transition frequency. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Collector Current (Max)	1	A
Collector-Emitter Breakdown Voltage (Max)	50	V
Power Dissipation (Max)	500	mW
Transition Frequency	150	MHz
DC Current Gain (hFE Min)	100	@ 100 mA, 2 V
Operating Temperature (Max)	150	°C
Package Type	TO-243AA (PCP)	Surface Mount
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the 2SB1122S-TD-E is determined by the following critical parameters:

Electrical Compatibility Requirements:

Transistor type must be PNP
Collector current rating must be equal to or greater than 1 A
Collector-emitter breakdown voltage must be equal to or greater than 50 V
Power dissipation must support 500 mW or higher
Transition frequency must be 150 MHz or higher
DC current gain (hFE) must meet or exceed 100 at specified test conditions
Operating temperature range must include 150°C

Mechanical Compatibility Requirements:

Surface mount mounting type
Package footprint compatibility with TO-243AA or equivalent land pattern
Moisture sensitivity level of 1 (Unlimited) or equivalent

Substitutes are grouped into three categories:

Direct Equivalents (Parametric Match): Parts with identical electrical specifications and packaging, differing only in packaging format (tape & reel versus cut tape).

Similar Equivalents (Enhanced Specifications): Parts that exceed the minimum electrical requirements while maintaining mechanical compatibility. These include higher current ratings, improved power dissipation, or enhanced frequency response.

Cross-Manufacturer Equivalents: Parts from alternative manufacturers meeting or exceeding all electrical and mechanical requirements with confirmed compatibility.

Parameter Comparison

Part Number	Manufacturer	Ic (Max)	Vce Breakdown (Max)	Power (Max)	fT	hFE (Min)	Package	Status
2SB1122S-TD-E	onsemi	1 A	50 V	500 mW	150 MHz	100	TO-243AA (PCP)	Obsolete
2SB1122T-TD-E	onsemi	1 A	50 V	500 mW	150 MHz	100	TO-243AA (PCP)	Obsolete
2SB1123S-TD-E	onsemi	2 A	50 V	500 mW	150 MHz	100	TO-243AA (PCP)	Active
2SB1123T-TD-E	onsemi	2 A	50 V	500 mW	150 MHz	200	TO-243AA (PCP)	Active
2SAR513PT100	Rohm Semiconductor	1 A	50 V	2 W	400 MHz	180	TO-243AA (MPT3)	Active
2SAR533PT100	Rohm Semiconductor	3 A	50 V	2 W	300 MHz	180	TO-243AA (MPT3)	Active
BCX51-10F	Nexperia USA Inc.	1 A	45 V	500 mW	145 MHz	63	TO-243AA (SOT-89)	Active
BCX51-10,115	Nexperia USA Inc.	1 A	45 V	1.3 W	145 MHz	63	TO-243AA (SOT-89)	Active
BCX51-16,115	Nexperia USA Inc.	1 A	45 V	1.3 W	145 MHz	100	TO-243AA (SOT-89)	Active
BCX51-16,135	Nexperia USA Inc.	1 A	45 V	1.3 W	145 MHz	100	TO-243AA (SOT-89)	Active
BCX51,115	NXP USA Inc.	1 A	45 V	1.3 W	145 MHz	63	TO-243AA (SOT-89)	Active

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications):

The 2SB1122T-TD-E is a parametric equivalent to the 2SB1122S-TD-E, differing only in packaging format (tape & reel versus cut tape). Both are classified as obsolete. This part maintains all electrical specifications and is suitable for direct substitution where packaging format is not a constraint.

For Active Product Substitution (Recommended for New Designs):

The 2SB1123S-TD-E and 2SB1123T-TD-E are active onsemi products with identical voltage and frequency ratings. These parts feature doubled collector current capability (2 A versus 1 A) while maintaining the same power dissipation and package footprint. Both are ROHS3 compliant and carry active product status, providing long-term availability and supply chain stability.

The 2SB1123T-TD-E additionally provides enhanced DC current gain (hFE = 200 minimum), improving circuit performance in applications requiring higher gain.

For Enhanced Performance Requirements:

The 2SAR513PT100 (Rohm Semiconductor) provides identical 1 A collector current and 50 V breakdown voltage with significant performance enhancements: 2 W power dissipation (4× improvement), 400 MHz transition frequency (2.67× improvement), and 180 minimum hFE. This part is active and ROHS3 compliant.

The 2SAR533PT100 (Rohm Semiconductor) extends collector current to 3 A while maintaining 50 V breakdown voltage, 2 W power dissipation, and active product status. This part is suitable for applications requiring higher current handling.

For Voltage-Constrained Applications:

The Nexperia BCX51 series (BCX51-10F, BCX51-10,115, BCX51-16,115, BCX51-16,135, BCX51,115) provides 1 A collector current with 45 V breakdown voltage. These parts are active, AEC-Q100 qualified for automotive applications, and ROHS3 compliant. The BCX51-16,115 and BCX51-16,135 variants offer 100 minimum hFE matching the original specification.

All recommended substitutes maintain surface mount TO-243AA package compatibility and MSL 1 (Unlimited) moisture sensitivity rating.

Frequently Asked Questions (FAQ)

Q: Can the 2SB1123S-TD-E directly replace the 2SB1122S-TD-E?

A: Yes. The 2SB1123S-TD-E is a direct mechanical and electrical substitute with identical voltage (50 V), frequency (150 MHz), and package specifications. The doubled collector current rating (2 A versus 1 A) provides additional design margin without affecting compatibility. Both parts use TO-243AA (PCP) surface mount packaging.

Q: What is the difference between 2SB1122S-TD-E and 2SB1122T-TD-E?

A: These parts are electrically identical with matching specifications for current, voltage, frequency, and gain. The difference is packaging format: the "S" variant uses cut tape packaging, while the "T" variant uses tape & reel. Both are obsolete onsemi products.

Q: Why are Rohm 2SAR513PT100 and 2SAR533PT100 listed as substitutes?

A: These parts meet or exceed all critical electrical parameters: 50 V breakdown voltage, PNP type, and surface mount TO-243AA package. The 2SAR513PT100 matches the 1 A current rating with enhanced power dissipation (2 W) and frequency response (400 MHz). The 2SAR533PT100 extends current capability to 3 A. Both are active products with ROHS3 compliance.

Q: Can BCX51 series parts replace the 2SB1122S-TD-E?

A: BCX51 series parts are suitable substitutes with the following considerations: they maintain 1 A collector current and TO-243AA package compatibility. However, the breakdown voltage is 45 V (versus 50 V), and transition frequency is 145 MHz (versus 150 MHz). These parts are active, AEC-Q100 qualified, and ROHS3 compliant. Application voltage margins must accommodate the 5 V reduction in breakdown voltage.

Q: What does "obsolete" product status mean for the 2SB1122S-TD-E?

A: Obsolete status indicates the manufacturer has discontinued production. The 2SB1122S-TD-E has limited remaining inventory (5600 pieces). For new designs or long-term production, active alternatives such as the 2SB1123S-TD-E, 2SAR513PT100, or BCX51 series are recommended to ensure supply chain continuity.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 Compliant status, matching the original 2SB1122S-TD-E specification. All parts also maintain MSL 1 (Unlimited) moisture sensitivity rating.

Q: What is the difference between PCP and SOT-89 package designations?

A: PCP and SOT-89 are equivalent package designations for the TO-243AA surface mount package. Both refer to the same three-lead configuration and land pattern. Parts designated as PCP (onsemi and Rohm) and SOT-89 (Nexperia) are mechanically interchangeable.

Q: Which substitute offers the best performance upgrade?

A: The 2SAR513PT100 provides the most significant performance enhancement: 4× power dissipation (2 W versus 500 mW), 2.67× frequency improvement (400 MHz versus 150 MHz), and 80% higher minimum gain (180 versus 100). This part maintains the 1 A current rating and 50 V voltage specification while offering active product status and ROHS3 compliance.

Q: Can I use a higher-current rated part like the 2SB1123S-TD-E in a circuit designed for 1 A?

A: Yes. Higher current ratings provide design margin without affecting circuit operation. The 2SB1123S-TD-E is rated for 2 A maximum collector current, making it suitable for applications requiring 1 A or less. The part maintains identical voltage, frequency, and package specifications.

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