2SB1203T-H Equivalent & Substitute Parts

Part Overview

The 2SB1203T-H is an obsolete PNP bipolar junction transistor manufactured by onsemi, rated for 50V collector-emitter breakdown voltage and 5A maximum collector current. This device is designed for through-hole mounting in TO-251-3 (IPak) package configuration and operates at a transition frequency of 130MHz with 1W maximum power dissipation. Due to its obsolete product status, equivalent and substitute parts are necessary for ongoing design support, production continuity, and component sourcing.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) (Max)	5	A
Voltage - Collector Emitter Breakdown (Max)	50	V
Vce Saturation (Max) @ Ib, Ic	550mV @ 150mA, 3A	—
Current - Collector Cutoff (Max)	1	µA
DC Current Gain (hFE) (Min) @ Ic, Vce	200 @ 500mA, 2V	—
Power - Max	1	W
Frequency - Transition	130	MHz
Operating Temperature (TJ)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-251-3 Short Leads, IPak, TO-251AA	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the 2SB1203T-H is determined by strict adherence to the following electrical and mechanical parameters:

Critical Parameters for Direct Substitution:

Transistor Type: PNP
Voltage - Collector Emitter Breakdown (Max): 50V
Current - Collector (Ic) (Max): 5A minimum
DC Current Gain (hFE) (Min): 200 @ 500mA, 2V
Mounting Type: Through Hole
Package / Case: TO-251-3 Short Leads, IPak, TO-251AA

Substitution Categories:

Direct Equivalent: Parts with identical electrical ratings and package specifications. The 2SB1203T-E qualifies as a parametric equivalent, offering the same 5A collector current, 50V breakdown voltage, and 1W power rating in the same TO-251-3 package. The primary distinction is product status: 2SB1203T-E is Active, whereas 2SB1203T-H is Obsolete.

Direct Substitute: Parts 2SA2039-E and 2SA2039-H provide direct substitution capability. Both maintain the 5A collector current and 50V breakdown voltage specifications. These parts feature enhanced transition frequency (360MHz versus 130MHz) and reduced power dissipation (800mW versus 1W), representing performance improvements within the same electrical class. Both are packaged in TO-251-3 configuration.

Similar Parts (Higher Current Rating): Parts 2SA2040-E and 2SB1204T-E are classified as similar rather than direct substitutes due to elevated maximum collector current ratings (8A versus 5A). These parts maintain 50V breakdown voltage and TO-251-3 packaging but exceed the current specification of the 2SB1203T-H. Selection of these parts is appropriate only when circuit design permits operation at higher current ratings.

Parameter Comparison

Parameter	2SB1203T-H (Main)	2SB1203T-E (Parametric Equivalent)	2SA2039-E (Direct Substitute)	2SA2039-H (Direct Substitute)	2SA2040-E (Similar)	2SB1204T-E (Similar)
Transistor Type	PNP	PNP	PNP	PNP	PNP	PNP
Current - Collector (Ic) (Max)	5 A	5 A	5 A	5 A	8 A	8 A
Voltage - Collector Emitter Breakdown (Max)	50 V	50 V	50 V	50 V	50 V	50 V
Vce Saturation (Max) @ Ib, Ic	550mV @ 150mA, 3A	550mV @ 150mA, 3A	430mV @ 100mA, 2A	430mV @ 100mA, 2A	400mV @ 40mA, 2A	500mV @ 200mA, 4A
Current - Collector Cutoff (Max)	1 µA	1 µA	1 µA	1 µA	100 nA	1 µA
DC Current Gain (hFE) (Min) @ Ic, Vce	200 @ 500mA, 2V	200 @ 500mA, 2V	200 @ 500mA, 2V	200 @ 500mA, 2V	200 @ 500mA, 2V	200 @ 500mA, 2V
Power - Max	1 W	1 W	800 mW	800 mW	1 W	1 W
Frequency - Transition	130 MHz	130 MHz	360 MHz	360 MHz	330 MHz	130 MHz
Operating Temperature (TJ)	150 °C	150 °C	150 °C	150 °C	150 °C	150 °C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	TO-251-3	TO-251-3	TO-251-3	TO-251-3	TO-251-3	TO-251-3
Product Status	Obsolete	Active	Obsolete	Obsolete	Obsolete	Obsolete
RoHS Status	Not Specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Preferred):

The 2SB1203T-E is the recommended parametric equivalent for the 2SB1203T-H. This part maintains identical electrical specifications across all critical parameters: 5A maximum collector current, 50V breakdown voltage, 1W power dissipation, and 130MHz transition frequency. The 2SB1203T-E is currently in Active product status, ensuring long-term availability and supply chain continuity. Both parts are ROHS3 compliant and carry REACH Unaffected designation, meeting current regulatory requirements.

For Direct Substitution (Functionally Equivalent):

The 2SA2039-E and 2SA2039-H provide direct substitution capability with enhanced performance characteristics. Both parts maintain the 5A collector current and 50V breakdown voltage specifications required for circuit compatibility. The 2SA2039 series offers superior transition frequency (360MHz) and lower saturation voltage, representing performance improvements suitable for applications where these enhancements do not conflict with circuit design constraints. Both parts are ROHS3 compliant.

For Higher Current Applications:

The 2SA2040-E and 2SB1204T-E are suitable only when circuit design permits operation at elevated collector current levels (8A maximum). These parts maintain 50V breakdown voltage and TO-251-3 packaging but should not be selected as direct replacements for 5A-rated designs unless circuit analysis confirms compatibility with higher current ratings.

Compliance Considerations:

All recommended substitute parts carry ROHS3 compliance and REACH Unaffected status, matching or exceeding the regulatory profile of the 2SB1203T-H. The 2SB1203T-E, as an Active product, provides superior long-term availability and supply security compared to Obsolete alternatives.

Frequently Asked Questions (FAQ)

Q: Can the 2SB1203T-E be used as a direct replacement for the 2SB1203T-H?

A: Yes. The 2SB1203T-E is a parametric equivalent offering identical electrical specifications: 5A maximum collector current, 50V breakdown voltage, 1W power dissipation, and 130MHz transition frequency. Both parts use the TO-251-3 package. The primary advantage of the 2SB1203T-E is its Active product status, ensuring ongoing availability.

Q: What is the difference between the 2SA2039-E and 2SA2039-H?

A: Both parts are electrically identical with 5A collector current and 50V breakdown voltage. The primary difference is packaging designation: 2SA2039-E is supplied in Bulk packaging, while 2SA2039-H does not specify packaging type. Both are suitable substitutes for the 2SB1203T-H.

Q: Can I use the 2SA2040-E in place of the 2SB1203T-H?

A: The 2SA2040-E is not a direct replacement. While it maintains 50V breakdown voltage and TO-251-3 packaging, it is rated for 8A maximum collector current versus 5A for the 2SB1203T-H. Selection of the 2SA2040-E is appropriate only when circuit design permits operation at higher current levels.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All recommended substitute parts (2SB1203T-E, 2SA2039-E, 2SA2039-H, 2SA2040-E, and 2SB1204T-E) are ROHS3 compliant. The 2SB1203T-H does not specify RoHS status in available documentation.

Q: What is the significance of transition frequency differences between these parts?

A: Transition frequency (fT) indicates the frequency at which transistor current gain drops to unity. The 2SB1203T-H operates at 130MHz, while 2SA2039 series parts operate at 360MHz. Higher transition frequency permits operation at higher signal frequencies but does not affect compatibility in lower-frequency applications. Circuit design determines whether enhanced frequency response is beneficial or irrelevant.

Q: Are there any thermal considerations when substituting these parts?

A: All parts operate at maximum junction temperature (TJ) of 150°C. The 2SA2039 series dissipates 800mW maximum versus 1W for the 2SB1203T-H. In thermally constrained applications, the 2SA2039 series may offer improved thermal performance due to lower power dissipation.

Q: Can I use these parts interchangeably in existing PCB designs?

A: Yes, provided the PCB is designed for TO-251-3 (IPak) through-hole mounting. All substitute parts use identical package configuration and pin assignment. No PCB modification is required for substitution.

Q: What is the inventory status of these parts?

A: The 2SB1203T-E (Active status) has 1069 pieces in stock. The 2SA2039-E has 8010 pieces available. The 2SA2040-E has 3950 pieces in stock. The 2SB1204T-E has 797 pieces available. Inventory levels support production requirements for all recommended substitutes.

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