BD135 NPN Bipolar Junction Transistor Equivalent & Substitute Parts

Part Overview

The BD135 is an NPN bipolar junction transistor manufactured by onsemi, rated for 45 V collector-emitter breakdown voltage and 1.5 A maximum collector current in a Through Hole TO-126 package. The original onsemi BD135 carries an Obsolete product status, necessitating identification of equivalent and substitute components for ongoing design support and procurement continuity. Active alternatives with identical or superior electrical specifications are available from onsemi and STMicroelectronics.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Current - Collector (Ic) Max	1.5	A
Voltage - Collector Emitter Breakdown (Max)	45	V
Vce Saturation (Max)	500	mV @ 50mA, 500mA
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) Min	40–100	@ 150mA, 2V
Power - Max	1.25	W
Operating Temperature	−55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-225AA, TO-126-3	—

Substitute Part Grouping Explanation

Substitution of the BD135 is determined by strict equivalence in the following electrical and mechanical parameters:

Transistor Type: NPN polarity must be maintained
Current Rating (Ic Max): 1.5 A collector current capacity
Voltage Rating (Vce Breakdown): 45 V minimum breakdown voltage
Saturation Voltage (Vce Sat): 500 mV maximum at specified base and collector currents
Leakage Current (ICBO): 100 nA maximum cutoff current
Power Dissipation: 1.25 W maximum
Operating Temperature Range: −55°C to 150°C junction temperature
Mounting and Package: Through Hole configuration compatible with TO-126 or TO-126-3 footprints

Substitute parts must satisfy all electrical parameters within the specified limits. DC Current Gain (hFE) variations within the range of 40–100 @ 150mA, 2V are acceptable as they remain within the functional operating envelope. Packaging format (Bulk, Tube) and RoHS compliance status do not affect electrical substitutability but influence procurement and regulatory requirements.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) A	Vce Breakdown (Max) V	Vce Sat (Max) mV	ICBO (Max) nA	hFE (Min) @ 150mA, 2V	Power (Max) W	Temp Range °C	Package	Product Status	RoHS Status
BD135	onsemi	1.5	45	500	100	40	1.25	−55 to 150	TO-126	Obsolete	Non-compliant
BD135G	onsemi	1.5	45	500	100	40	1.25	−55 to 150	TO-126	Active	ROHS3 Compliant
BD13510STU	onsemi	1.5	45	500	100	63	1.25	−55 to 150	TO-126-3	Active	ROHS3 Compliant
BD13516S	onsemi	1.5	45	500	100	100	1.25	−55 to 150	TO-126-3	Last Time Buy	ROHS3 Compliant
BD13516STU	onsemi	1.5	45	500	100	100	1.25	−55 to 150	TO-126-3	Active	ROHS3 Compliant
BD135	STMicroelectronics	1.5	45	500	100	40	1.25	−55 to 150	SOT-32-3	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: BD135G (onsemi)

BD135G is the direct Active equivalent of the obsolete onsemi BD135. It maintains identical electrical specifications (Ic 1.5 A, Vce 45 V, hFE 40 @ 150mA, 2V) and is ROHS3 compliant. The TO-126 package footprint is mechanically and electrically interchangeable with the original part. This is the preferred substitution path for designs currently using the obsolete BD135.

Secondary Recommendation: BD13516STU (onsemi)

BD13516STU provides Active product status with enhanced DC Current Gain (hFE 100 @ 150mA, 2V) compared to the original specification (hFE 40). All other electrical parameters remain equivalent. The TO-126-3 package is mechanically compatible with TO-126 footprints. ROHS3 compliance is confirmed. This option is suitable for applications where higher current gain provides design margin.

Alternative Recommendation: BD135 (STMicroelectronics)

The STMicroelectronics BD135 maintains identical electrical specifications to the onsemi original and carries Active product status with ROHS3 compliance. The SOT-32-3 package is mechanically equivalent to TO-126-3. This option provides cross-manufacturer sourcing flexibility.

Not Recommended for New Designs: BD13516S (onsemi)

BD13516S carries Last Time Buy status, indicating discontinued production. While electrically equivalent, procurement of this part is not recommended for new designs or long-term production requirements.

Frequently Asked Questions (FAQ)

Q: Can BD135G be used as a direct replacement for the obsolete BD135?

A: Yes. BD135G is electrically and mechanically identical to the original onsemi BD135. All electrical parameters (Ic, Vce, saturation voltage, leakage current, power rating, and temperature range) are equivalent. The TO-126 package footprint is identical. BD135G is the recommended direct substitute.

Q: What is the difference between BD135G and BD13516STU?

A: Both parts are electrically equivalent in all parameters except DC Current Gain (hFE). BD135G specifies hFE minimum of 40 @ 150mA, 2V, while BD13516STU specifies hFE minimum of 100 @ 150mA, 2V. Both are Active products with ROHS3 compliance. The choice depends on circuit design requirements for current gain. BD13516STU provides higher gain margin.

Q: Are the TO-126 and TO-126-3 packages mechanically interchangeable?

A: Yes. Both packages are Through Hole configurations with identical pin assignments and footprint compatibility. The designations refer to the same physical package with minor nomenclature variations across manufacturers.

Q: Is the STMicroelectronics BD135 compatible with designs using the onsemi BD135?

A: Yes. The STMicroelectronics BD135 maintains identical electrical specifications and is housed in the SOT-32-3 package, which is mechanically equivalent to TO-126-3. Both are Active products with ROHS3 compliance. Cross-manufacturer substitution is electrically valid.

Q: Why should BD13516S not be selected for new designs?

A: BD13516S carries Last Time Buy product status, indicating that onsemi has discontinued production and will not accept new orders beyond a specified cutoff date. For new designs requiring long-term component availability, BD135G or BD13516STU are recommended.

Q: Does RoHS compliance affect the electrical performance of the substitute parts?

A: No. RoHS compliance is a regulatory and manufacturing requirement that does not alter electrical performance. All ROHS3-compliant substitutes maintain identical electrical specifications to the original part. RoHS compliance is relevant for applications subject to regulatory requirements in specific markets or industries.

Q: Can I use BD13510STU as a substitute?

A: Yes. BD13510STU is electrically equivalent with all parameters matching the original BD135 specification. It carries Active product status and ROHS3 compliance. The DC Current Gain (hFE 63 @ 150mA, 2V) falls within the acceptable range for substitution. The TO-126-3 package is mechanically compatible.

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