BCW71_D87Z NPN Bipolar Junction Transistor Equivalent & Substitute Parts

Part Overview

The BCW71_D87Z is an NPN bipolar junction transistor manufactured by onsemi, designed for surface mount applications in the SOT-23-3 package. This device operates at a maximum collector current of 500 mA with a collector-emitter breakdown voltage of 45 V and a transition frequency of 330 MHz. The BCW71_D87Z is classified as an obsolete product with limited inventory availability (742 pieces in stock). Due to its obsolete status and restricted availability, identifying equivalent and substitute parts from active product lines is essential for design continuity and procurement reliability.

Key Parameters

Parameter	BCW71_D87Z	Unit
Transistor Type	NPN	—
Current - Collector (Ic) Max	500	mA
Voltage - Collector Emitter Breakdown (Max)	45	V
Vce Saturation (Max) @ Ib, Ic	250 mV @ 500 µA, 10 mA	—
Current - Collector Cutoff (Max)	100	µA
DC Current Gain (hFE) Min @ Ic, Vce	110 @ 2 mA, 5 V	—
Power - Max	350	mW
Frequency - Transition	330	MHz
Operating Temperature Range	-55 to 150	°C
Package / Case	SOT-23-3	—
Mounting Type	Surface Mount	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the BCW71_D87Z is determined by strict alignment of the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor type: NPN configuration
Package: SOT-23-3 (TO-236-3, SC-59)
Mounting type: Surface Mount
Collector-emitter breakdown voltage: 45 V minimum
Maximum collector current: 500 mA or greater
Power dissipation: 300 mW or greater
Operating temperature range: -55°C to 150°C or wider

Substitution Groups:

Group 1: Full Current Capability (500 mA) Substitutes Parts that maintain the full 500 mA collector current rating with 45 V breakdown voltage. These include BC817-16LT1G, BC817-16LT3G, BC817-40LT1G, BC817-40LT3G, and BCX19LT1G. All are active products with RoHS3 compliance and unlimited moisture sensitivity level (MSL 1).

Group 2: Reduced Current Capability (100 mA) Substitutes Parts with lower maximum collector current (100 mA) but matching 45 V breakdown voltage and SOT-23-3 package. These include BC847ALT1G, BC847BLT3G, BC847CLT1G, and BC847CLT3G. These are suitable only for applications where collector current does not exceed 100 mA.

Group 3: Reduced Voltage Capability (40 V) Substitutes The MMBT3904LT1G operates at 40 V breakdown voltage with 200 mA maximum collector current. This part is suitable only for applications where the 45 V rating is not a hard requirement.

Parameter Comparison

Part Number	Manufacturer	Ic Max (mA)	Vce Breakdown (V)	Vce Sat (mV)	hFE Min	Freq (MHz)	Power (mW)	Temp Range (°C)	Status	RoHS
BCW71_D87Z	onsemi	500	45	250 @ 500µA, 10mA	110 @ 2mA, 5V	330	350	-55 to 150	Obsolete	—
BC817-16LT1G	onsemi	500	45	700 @ 50mA, 500mA	100 @ 100mA, 1V	100	300	-65 to 150	Active	ROHS3
BC817-16LT3G	onsemi	500	45	700 @ 50mA, 500mA	100 @ 100mA, 1V	100	300	-65 to 150	Active	ROHS3
BC817-40LT1G	onsemi	500	45	700 @ 50mA, 500mA	250 @ 100mA, 1V	100	300	-65 to 150	Active	ROHS3
BC817-40LT3G	onsemi	500	45	700 @ 50mA, 500mA	250 @ 100mA, 1V	100	300	-65 to 150	Active	ROHS3
BC847ALT1G	onsemi	100	45	600 @ 5mA, 100mA	110 @ 2mA, 5V	100	300	-55 to 150	Active	ROHS3
BC847BLT3G	onsemi	100	45	600 @ 5mA, 100mA	200 @ 2mA, 5V	100	300	-55 to 150	Active	ROHS3
BC847CLT1G	onsemi	100	45	600 @ 5mA, 100mA	420 @ 2mA, 5V	100	300	-55 to 150	Active	ROHS3
BC847CLT3G	onsemi	100	45	600 @ 5mA, 100mA	420 @ 2mA, 5V	100	300	-55 to 150	Active	ROHS3
BCX19LT1G	onsemi	500	45	620 @ 50mA, 500mA	100 @ 100mA, 1V	—	300	-55 to 150	Active	ROHS3
MMBT3904LT1G	onsemi	200	40	300 @ 5mA, 50mA	100 @ 10mA, 1V	300	300	-55 to 150	Active	ROHS3

Engineering Selection Recommendations

For Direct Replacement (Full Electrical Equivalence):

The BC817-16LT1G, BC817-16LT3G, BC817-40LT1G, BC817-40LT3G, and BCX19LT1G are the primary substitutes for the BCW71_D87Z. All maintain the 500 mA collector current rating and 45 V breakdown voltage. These parts are active products with RoHS3 compliance and unlimited moisture sensitivity level. The BC817 series variants differ in DC current gain (hFE) specifications and packaging format (Cut Tape vs. Tape & Reel). The BCX19LT1G offers equivalent electrical performance with active product status and RoHS3 compliance.

For Current-Limited Applications (100 mA Maximum):

The BC847ALT1G, BC847BLT3G, BC847CLT1G, and BC847CLT3G are suitable substitutes only when the application circuit limits collector current to 100 mA or less. These parts maintain the 45 V breakdown voltage and SOT-23-3 package. The BC847 series variants differ in DC current gain specifications. All are active products with RoHS3 compliance.

For Reduced Voltage Applications (40 V Acceptable):

The MMBT3904LT1G is a substitute only when the application does not require the full 45 V breakdown voltage rating. This part operates at 40 V with a maximum collector current of 200 mA. It is an active product with RoHS3 compliance and 300 MHz transition frequency.

Packaging Considerations:

All substitute parts are available in SOT-23-3 package with surface mount mounting type. The BC817 and BC847 series are available in both Cut Tape (CT) & Digi-Reel® and Tape & Reel (TR) packaging formats. Inventory availability varies: BC817-16LT1G (305,400 pcs), BC817-40LT1G (305,000 pcs), BC847CLT1G (80,100 pcs), and BCX19LT1G (110,100 pcs) offer substantial stock levels.

Compliance Status:

All active substitute parts carry RoHS3 compliance and REACH Unaffected status, matching the regulatory requirements of the obsolete BCW71_D87Z. Moisture sensitivity level is MSL 1 (Unlimited) for all parts.

Frequently Asked Questions (FAQ)

Q: Can I use BC847 series parts as direct replacements for BCW71_D87Z?

A: BC847 series parts (BC847ALT1G, BC847BLT3G, BC847CLT1G, BC847CLT3G) are not direct replacements because they have a maximum collector current rating of 100 mA, while the BCW71_D87Z is rated for 500 mA. Use BC847 parts only if your circuit design limits collector current to 100 mA or less.

Q: What is the difference between BC817-16LT1G and BC817-40LT1G?

A: Both parts have identical electrical ratings (500 mA, 45 V, 100 MHz, 300 mW). The primary difference is DC current gain: BC817-16LT1G has hFE minimum of 100 @ 100 mA, 1V, while BC817-40LT1G has hFE minimum of 250 @ 100 mA, 1V. The "-16" and "-40" designations refer to these gain classifications. Select based on your circuit's base drive requirements.

Q: Can I substitute MMBT3904LT1G for BCW71_D87Z?

A: MMBT3904LT1G is not a direct substitute. It operates at 40 V breakdown voltage (versus 45 V for BCW71_D87Z) and has a maximum collector current of 200 mA (versus 500 mA). Use MMBT3904LT1G only if your application does not require the full 45 V rating and collector current does not exceed 200 mA.

Q: What is the difference between Cut Tape (CT) & Digi-Reel® and Tape & Reel (TR) packaging?

A: Both packaging formats contain the same electronic component in SOT-23-3 package. Cut Tape format is suitable for smaller volume orders and manual assembly. Tape & Reel format is optimized for high-volume automated assembly. Electrical performance is identical; selection depends on manufacturing process requirements.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All active substitute parts listed (BC817 series, BC847 series, BCX19LT1G, and MMBT3904LT1G) carry RoHS3 compliance certification. The obsolete BCW71_D87Z does not have RoHS status specified.

Q: Which substitute part has the highest inventory availability?

A: BC817-16LT1G and BC817-40LT1G both have 305,000+ pieces in stock, providing the highest inventory availability among all substitutes. These parts are recommended for procurement reliability.

Q: Does transition frequency matter when selecting a substitute?

A: Transition frequency (fT) affects high-frequency performance. The BCW71_D87Z has 330 MHz fT, while BC817 and BC847 series have 100 MHz fT. For applications operating below 100 MHz, this difference is not critical. For applications requiring frequencies above 100 MHz, verify that the substitute part's 100 MHz rating is sufficient for your circuit design.

Q: What is the significance of Vce saturation specifications?

A: Vce saturation indicates the voltage drop across the transistor when fully saturated (conducting at maximum). BCW71_D87Z specifies 250 mV @ 500 µA, 10 mA, while BC817 series specifies 700 mV @ 50 mA, 500 mA. Higher saturation voltage results in greater power dissipation. Verify that your circuit design can tolerate the saturation voltage of the substitute part.

Q: Can I mix different BC817 variants in the same design?

A: Yes, BC817-16LT1G, BC817-16LT3G, BC817-40LT1G, and BC817-40LT3G can be used interchangeably from an electrical standpoint. The "-16" and "-40" designations indicate different DC current gain ranges. Select the variant that matches your circuit's base drive and gain requirements. The "LT1G" and "LT3G" suffixes indicate different packaging formats (Cut Tape vs. Tape & Reel) with identical electrical performance.

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