BCP51 PNP Bipolar Transistor Equivalent & Substitute Parts

Part Overview

The BCP51 is a PNP bipolar junction transistor manufactured by onsemi, rated for 45 V collector-emitter breakdown voltage and 1.5 A maximum collector current in a surface mount SOT-223-4 package. The device is classified as obsolete, necessitating identification of active equivalent and substitute components for new designs and production continuity. Substitute parts must maintain electrical compatibility within the specified parameter ranges while offering active product status and current manufacturing support.

Key Parameters

Parameter	BCP51 Value	Unit
Transistor Type	PNP	—
Collector Current (Ic) Max	1.5	A
Collector-Emitter Breakdown Voltage (Max)	45	V
Vce Saturation (Max)	500	mV @ 50mA, 500mA
DC Current Gain (hFE) Min	40	@ 150mA, 2V
Power Dissipation (Max)	1	W
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package	SOT-223-4 (TO-261-4)	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitute parts for the BCP51 are classified into two categories based on electrical parameter compatibility:

Direct Voltage/Current Equivalents: Parts maintaining the 45 V minimum collector-emitter breakdown voltage and 1.5 A collector current rating. The BCP53T1G qualifies as a direct substitute with superior voltage rating (80 V) and power dissipation (1.5 W), ensuring operation within all BCP51 application parameters.

Higher Current Capability Substitutes: Parts rated for 3 A collector current at 40 V breakdown voltage. These include FZT790A, NJT4030PT1G, NJT4030PT3G, NJV4030PT1G, NJV4030PT3G, NSS40300MZ4T1G, and NSS40300MZ4T3G. These devices exceed the BCP51 current specification and operate at slightly lower voltage ratings (40 V), suitable for applications where the 1.5 A limit is insufficient but voltage headroom remains adequate.

Lower Current Capability Substitutes: The PZT2907AT1G is rated for 600 mA maximum collector current at 60 V breakdown voltage. This part is applicable only to circuits where collector current does not exceed 600 mA.

Substitution eligibility is determined by:

Transistor type (PNP)
Collector current rating (equal to or greater than 1.5 A for direct substitution)
Collector-emitter breakdown voltage (equal to or greater than 45 V for direct substitution)
Surface mount SOT-223 package compatibility
Operating temperature range overlap (-55°C to 150°C)

Parameter Comparison

Part Number	Manufacturer	Ic Max (A)	Vce Breakdown (V)	Vce Sat (mV)	hFE Min	Power Max (W)	Freq Trans (MHz)	Status	Package
BCP51	onsemi	1.5	45	500 @ 50mA, 500mA	40 @ 150mA, 2V	1	—	Obsolete	SOT-223-4
BCP53T1G	onsemi	1.5	80	500 @ 50mA, 500mA	40 @ 150mA, 2V	1.5	50	Active	SOT-223
FZT790A	onsemi	3	40	750 @ 50mA, 2A	300 @ 10mA, 2V	2	100	Active	SOT-223-4
NJT4030PT1G	onsemi	3	40	500 @ 300mA, 3A	200 @ 1A, 1V	2	160	Active	SOT-223
NJT4030PT3G	onsemi	3	40	500 @ 300mA, 3A	200 @ 1A, 1V	2	160	Active	SOT-223
NJV4030PT1G	onsemi	3	40	500 @ 300mA, 3A	200 @ 1A, 1V	2	160	Active	SOT-223
NJV4030PT3G	onsemi	3	40	500 @ 300mA, 3A	200 @ 1A, 1V	2	160	Active	SOT-223
NSS40300MZ4T1G	onsemi	3	40	400 @ 300mA, 3A	175 @ 1A, 1V	2	160	Active	SOT-223
NSS40300MZ4T3G	onsemi	3	40	400 @ 300mA, 3A	175 @ 1A, 1V	2	160	Active	SOT-223
NSV40300MZ4T1G	Sanyo	3	40	400 @ 300mA, 3A	175 @ 1A, 1V	2	160	Active	SOT-223
PZT2907AT1G	onsemi	0.6	60	1.6 @ 50mA, 500mA	100 @ 150mA, 10V	1.5	200	Active	SOT-223

Engineering Selection Recommendations

Primary Substitute: BCP53T1G

The BCP53T1G is the recommended direct substitute for the obsolete BCP51. This onsemi device maintains identical collector current (1.5 A) and saturation voltage specifications while providing enhanced voltage rating (80 V vs. 45 V) and increased power dissipation capability (1.5 W vs. 1 W). The BCP53T1G carries active product status with RoHS3 compliance and unlimited moisture sensitivity level. The device is available in high inventory quantities (105,100 pcs) and is packaged in SOT-223 (TO-261), maintaining mechanical compatibility with the original BCP51 footprint.

Secondary Substitutes: Higher Current Devices (3 A Rating)

For applications requiring collector current exceeding 1.5 A but not exceeding 3 A, the following active devices are suitable:

FZT790A (onsemi): 3 A, 40 V, 100 MHz transition frequency, 2 W power dissipation. RoHS3 compliant. Inventory: 7,960 pcs.
NJT4030PT1G / NJT4030PT3G (onsemi): 3 A, 40 V, 160 MHz transition frequency, 2 W power dissipation. RoHS3 compliant. Inventory: 35,100 pcs (PT1G) and 1,796 pcs (PT3G).
NJV4030PT1G / NJV4030PT3G (onsemi): 3 A, 40 V, 160 MHz transition frequency, 2 W power dissipation. RoHS3 compliant. Tape & Reel packaging. Inventory: 12,863 pcs (PT1G) and 5,400 pcs (PT3G).
NSS40300MZ4T1G / NSS40300MZ4T3G (onsemi): 3 A, 40 V, 160 MHz transition frequency, 2 W power dissipation, 400 mV saturation voltage. RoHS3 compliant. Inventory: 14,402 pcs (T1G) and 12,863 pcs (T3G).
NSV40300MZ4T1G (Sanyo): 3 A, 40 V, 160 MHz transition frequency, 2 W power dissipation, 400 mV saturation voltage. Active status. Inventory: 12,963 pcs.

These devices operate at 40 V collector-emitter breakdown voltage, which is 5 V below the BCP51 specification. Circuit designs must confirm that maximum supply voltages do not exceed 40 V.

Tertiary Substitute: Lower Current Device

The PZT2907AT1G (onsemi) is applicable only to circuits where collector current does not exceed 600 mA. This device provides 60 V breakdown voltage and 200 MHz transition frequency with RoHS3 compliance and active product status. Inventory: 125,200 pcs.

All recommended substitutes maintain surface mount SOT-223 package compatibility, operating temperature range overlap, and REACH compliance status with the original BCP51.

Frequently Asked Questions (FAQ)

Q: Can the BCP53T1G directly replace the BCP51 in all applications?

A: The BCP53T1G is electrically compatible with the BCP51 for all applications where the original device operates within its 1.5 A and 45 V specifications. The BCP53T1G provides superior voltage rating (80 V) and power dissipation (1.5 W), ensuring operation within all BCP51 parameter ranges. Mechanical compatibility is maintained through identical SOT-223 package pinout.

Q: What is the difference between the 3 A rated devices and the BCP51?

A: The 3 A rated devices (FZT790A, NJT4030 series, NSS40300 series, NSV40300 series) provide double the collector current capability but operate at 40 V breakdown voltage compared to the BCP51's 45 V rating. These devices are suitable for applications requiring higher current handling. Circuit designs must confirm that maximum supply voltages do not exceed 40 V.

Q: Are there packaging differences between substitute parts?

A: All substitute parts are packaged in SOT-223 or SOT-223-4 surface mount packages with TO-261-4 or TO-261AA mechanical equivalence. Packaging variants include Cut Tape (CT) & Digi-Reel®, Tape & Reel (TR), and Bulk options. PCB footprints are compatible across all listed substitutes.

Q: What is the significance of the different part number suffixes (PT1G, PT3G, MZ4T1G, MZ4T3G)?

A: Part number suffixes indicate manufacturing date codes and packaging configurations. Electrical specifications remain identical across suffix variations for the same base part number. Selection should be based on available inventory and packaging requirements (Cut Tape, Tape & Reel, or Bulk).

Q: Which substitute offers the best saturation voltage performance?

A: The NSS40300MZ4T1G and NSS40300MZ4T3G devices provide 400 mV saturation voltage at 300 mA and 3 A conditions, compared to the BCP51's 500 mV specification. This represents improved switching efficiency for high-current applications.

Q: Is the PZT2907AT1G suitable for general BCP51 replacement?

A: The PZT2907AT1G is not a general replacement due to its 600 mA maximum collector current rating, which is 60% of the BCP51's 1.5 A specification. This device is applicable only to circuits confirmed to operate below 600 mA collector current.

Q: What compliance certifications apply to the substitute parts?

A: All active substitute parts listed carry RoHS3 compliance and REACH Unaffected status. Moisture sensitivity level is 1 (Unlimited) for all devices, matching the BCP51 specification. ECCN classification is EAR99 for all onsemi and Sanyo devices.

Q: Can I use the higher voltage rated BCP53T1G in place of the BCP51 without circuit modifications?

A: Yes. The BCP53T1G's 80 V rating provides additional voltage margin without requiring circuit modifications. The device maintains identical current and saturation voltage specifications, ensuring direct functional compatibility.

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