BD1356STU Equivalent & Substitute Parts

Part Overview

The BD1356STU 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 TO-126-3 through-hole package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. The BD1356STU serves in general-purpose switching and amplification circuits where moderate voltage and current handling are required.

Key Parameters

Parameter	Value
Transistor Type	NPN
Current - Collector (Ic) (Max)	1.5 A
Voltage - Collector Emitter Breakdown (Max)	45 V
Vce Saturation (Max) @ Ib, Ic	500mV @ 50mA, 500mA
Current - Collector Cutoff (Max)	100nA (ICBO)
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 150mA, 2V
Power - Max	1.25 W
Operating Temperature (TJ)	150°C
Mounting Type	Through Hole
Package / Case	TO-225AA, TO-126-3
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the BD1356STU is determined by electrical and mechanical parameter compatibility. All substitute parts must maintain the following core specifications:

Electrical Parameters (Critical for Substitution):

Transistor Type: NPN
Current - Collector (Ic) (Max): 1.5 A
Voltage - Collector Emitter Breakdown (Max): 45 V
Vce Saturation (Max) @ Ib, Ic: 500mV @ 50mA, 500mA
Current - Collector Cutoff (Max): 100nA (ICBO)
Power - Max: 1.25 W

Mechanical Parameters (Critical for Substitution):

Mounting Type: Through Hole
Package / Case: TO-225AA, TO-126-3 or equivalent through-hole package

DC Current Gain Consideration: The BD1356STU specifies DC Current Gain (hFE) minimum of 40 @ 150mA, 2V. Substitute parts with higher hFE values (such as BD13516STU at 100 @ 150mA, 2V) remain electrically compatible as they exceed the minimum specification.

Operating Temperature Range: The BD1356STU operates to 150°C maximum junction temperature. Substitute parts with extended operating temperature ranges (-55°C to 150°C) provide broader environmental capability while maintaining compatibility.

Parameter Comparison

Part Number	Manufacturer	Product Status	Ic (Max)	Vce Breakdown (Max)	Vce Sat (Max)	hFE (Min)	Power (Max)	Package	Operating Temp (TJ)	RoHS Status
BD1356STU	onsemi	Obsolete	1.5 A	45 V	500mV @ 50mA, 500mA	40 @ 150mA, 2V	1.25 W	TO-126-3	150°C	Not Specified
BD135G	onsemi	Active	1.5 A	45 V	500mV @ 50mA, 500mA	40 @ 150mA, 2V	1.25 W	TO-126	-55°C ~ 150°C	ROHS3 Compliant
BD135TG	onsemi	Last Time Buy	1.5 A	45 V	500mV @ 50mA, 500mA	40 @ 150mA, 2V	1.25 W	TO-126	-55°C ~ 150°C	ROHS3 Compliant
BD13516STU	onsemi	Active	1.5 A	45 V	500mV @ 50mA, 500mA	100 @ 150mA, 2V	1.25 W	TO-126-3	150°C	ROHS3 Compliant
BD135-16	STMicroelectronics	Not For New Designs	1.5 A	45 V	500mV @ 50mA, 500mA	40 @ 150mA, 2V	1.25 W	SOT-32	150°C	ROHS3 Compliant
BD135	STMicroelectronics	Active	1.5 A	45 V	500mV @ 50mA, 500mA	40 @ 150mA, 2V	1.25 W	SOT-32-3	150°C	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: BD13516STU

The BD13516STU is the preferred substitute for the BD1356STU. Both parts are manufactured by onsemi and share identical electrical specifications with the exception of DC Current Gain (hFE), where BD13516STU exceeds the minimum requirement. The BD13516STU maintains the same TO-126-3 package configuration, eliminating any mechanical redesign requirements. The part is currently in active production status with ROHS3 compliance and 1900 units in stock inventory.

Secondary Recommendation: BD135G

The BD135G is an active onsemi product with full electrical compatibility to the BD1356STU. It provides extended operating temperature range (-55°C to 150°C) and ROHS3 compliance. The package designation differs slightly (TO-126 versus TO-126-3), but both are through-hole TO-126 variants with compatible pinouts. BD135G has 2369 units in stock inventory.

Alternative Recommendation: BD135

The BD135 manufactured by STMicroelectronics is an active product with identical electrical specifications to the BD1356STU. It provides ROHS3 compliance and the highest inventory availability (26500 units). The package is SOT-32-3, which is a through-hole configuration compatible with TO-126-3 footprints. This part is suitable for applications where cross-manufacturer sourcing is acceptable.

Not Recommended for New Designs: BD135TG and BD135-16

BD135TG carries a Last Time Buy status, indicating limited future availability. BD135-16 is marked Not For New Designs by STMicroelectronics, restricting its use to legacy system maintenance only.

Frequently Asked Questions (FAQ)

Q: Can BD135G directly replace BD1356STU in existing designs?

A: Yes. BD135G maintains all critical electrical parameters (1.5 A collector current, 45 V breakdown voltage, 500mV saturation voltage, 1.25 W power rating) and uses a compatible through-hole package. The primary difference is extended operating temperature range and ROHS3 compliance, both of which are improvements over the obsolete BD1356STU.

Q: What is the difference between BD13516STU and BD1356STU?

A: Both parts are onsemi NPN transistors with identical voltage and current ratings in the same TO-126-3 package. The BD13516STU has a higher minimum DC Current Gain (hFE) of 100 @ 150mA, 2V compared to 40 @ 150mA, 2V for the BD1356STU. This higher gain does not create compatibility issues; it represents an improved specification. BD13516STU is currently active in production.

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

A: TO-126 and TO-126-3 are both three-lead through-hole packages with identical pinout and mechanical dimensions. They are functionally interchangeable for PCB mounting purposes. The "-3" designation indicates a specific variant, but both accommodate the same footprint.

Q: Why does BD135 use SOT-32-3 package instead of TO-126-3?

A: SOT-32-3 and TO-126-3 are equivalent package designations for the same three-lead through-hole transistor package. Different manufacturers use different naming conventions. Both packages have identical pinout and mounting footprint compatibility.

Q: Is BD135G suitable for applications requiring extended temperature operation?

A: Yes. BD135G operates from -55°C to 150°C junction temperature, providing a wider operating range than the BD1356STU specification of 150°C maximum. This extended range is beneficial for applications exposed to low-temperature environments.

Q: What is the inventory status for substitute parts?

A: BD135 has the highest inventory (26500 units), followed by BD135G (2369 units) and BD13516STU (1900 units). BD135TG has 1451 units but carries Last Time Buy status. BD135-16 has 9916 units but is marked Not For New Designs.

Q: Can I use BD135-16 as a substitute?

A: BD135-16 meets all electrical specifications but is designated Not For New Designs by STMicroelectronics. It is suitable only for maintenance and repair of existing systems using this part. For new production, use BD135, BD135G, or BD13516STU instead.

Q: Does hFE variation affect circuit performance?

A: DC Current Gain (hFE) affects base current requirements for saturation. Higher hFE values (such as BD13516STU at 100) require less base current to achieve the same collector current. This is generally beneficial for circuit design, reducing base drive requirements. All substitute parts maintain saturation voltage specifications, ensuring compatible switching performance.

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