BSS64 Equivalent & Substitute Parts

Part Overview

The BSS64 is an NPN bipolar junction transistor manufactured by onsemi, designed for general-purpose switching and amplification applications. The device features an 80 V collector-emitter breakdown voltage, 200 mA maximum collector current, and 350 mW power dissipation in a surface mount SOT-23-3 package. The BSS64 is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. Substitute parts must maintain compatibility with existing PCB layouts while meeting or exceeding the electrical performance requirements of the original specification.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	80	V
Current - Collector (Ic) (Max)	200	mA
Power - Max	350	mW
Frequency - Transition	60	MHz
Operating Temperature Range	-55 to 150	°C
Package / Case	SOT-23-3	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the BSS64 is determined by the following critical parameters: transistor type (NPN), collector-emitter breakdown voltage (80 V minimum), maximum collector current (200 mA minimum), power dissipation capability (350 mW minimum), and package compatibility (SOT-23-3 surface mount). Substitute parts are grouped into two categories based on these constraints:

Category 1: Direct Electrical Equivalents (80 V, 200 mA minimum) Parts that maintain the 80 V breakdown voltage and 200 mA collector current rating, ensuring drop-in compatibility for applications requiring the original BSS64 specifications.

Category 2: Enhanced Performance Alternatives (80 V, higher current capability) Parts that exceed the 200 mA collector current specification while maintaining 80 V breakdown voltage, suitable for applications where increased current handling is beneficial and power dissipation limits are not exceeded.

Category 3: Reduced Specification Alternatives (80 V, lower current capability) Parts that operate at 80 V breakdown voltage but with reduced collector current ratings, applicable only when circuit design permits lower current operation.

Category 4: Voltage-Reduced Alternatives (lower voltage, 200 mA current) Parts with reduced breakdown voltage specifications, usable only in applications where the lower voltage rating is acceptable.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) V	Power mW	Frequency MHz	Package	Product Status
BSS64	onsemi	200	80	350	60	SOT-23-3	Obsolete
BSS64LT1G	onsemi	100	80	225	60	SOT-23-3	Active
MMBT8099LT1G	onsemi	500	80	225	150	SOT-23-3	Active
MMBTA06LT1G	onsemi	500	80	225	100	SOT-23-3	Active
MMBT6429LT1G	onsemi	200	45	225	700	SOT-23-3	Active
2SCR514RTL	Rohm Semiconductor	700	80	1000	320	TSMT3	Active
BSS64,215	Nexperia USA Inc.	100	80	250	100	SOT-23-3	Not For New Designs
FMMT620TA	Diodes Incorporated	1500	80	625	160	SOT-23-3	Active

Engineering Selection Recommendations

For Direct Replacement in Active Production: BSS64LT1G (onsemi) is the primary active equivalent from the original manufacturer. This part maintains the 80 V breakdown voltage and SOT-23-3 package, with reduced collector current (100 mA) and power dissipation (225 mW). Selection is appropriate when circuit design permits the lower current specification. Product status is Active with full RoHS3 compliance.

For Enhanced Current Capability (80 V, SOT-23-3): MMBT8099LT1G and MMBTA06LT1G both provide 500 mA collector current at 80 V breakdown voltage in SOT-23-3 packages. Both are Active products with RoHS3 compliance. MMBT8099LT1G offers 150 MHz transition frequency, while MMBTA06LT1G provides 100 MHz. Selection depends on frequency requirements and available inventory.

For Maximum Current Capability (80 V): FMMT620TA (Diodes Incorporated) provides 1.5 A collector current at 80 V in SOT-23-3 package with 625 mW power dissipation. This part is Active and RoHS3 compliant, suitable for applications requiring significantly higher current handling than the original BSS64.

For Alternative Packaging (80 V, higher current): 2SCR514RTL (Rohm Semiconductor) provides 700 mA at 80 V in TSMT3 package with 1 W power dissipation. This part requires PCB layout modification due to different package geometry. Product status is Active with RoHS3 compliance and AEC-Q101 automotive qualification.

Not Recommended for New Designs: BSS64,215 (Nexperia USA Inc.) carries "Not For New Designs" status despite Active inventory. This part is suitable only for legacy system maintenance where existing designs are locked.

Not Suitable as Direct Replacement: MMBT6429LT1G features reduced breakdown voltage (45 V) and is applicable only in applications where the lower voltage specification is acceptable.

Frequently Asked Questions (FAQ)

Q: Can BSS64LT1G directly replace BSS64 in all applications? A: BSS64LT1G maintains the same 80 V breakdown voltage and SOT-23-3 package as BSS64. However, collector current is reduced from 200 mA to 100 mA, and power dissipation decreases from 350 mW to 225 mW. Direct replacement is valid only when circuit design operates at or below 100 mA collector current.

Q: What is the difference between MMBT8099LT1G and MMBTA06LT1G? A: Both parts provide 500 mA at 80 V in SOT-23-3 packages with 225 mW power dissipation. MMBT8099LT1G features 150 MHz transition frequency, while MMBTA06LT1G operates at 100 MHz. Selection depends on frequency requirements and application bandwidth constraints.

Q: Why does MMBT6429LT1G have a lower breakdown voltage? A: MMBT6429LT1G is specified for 45 V breakdown voltage, making it unsuitable as a direct BSS64 replacement in circuits requiring 80 V operation. This part is applicable only in lower-voltage applications where the reduced voltage specification is acceptable.

Q: Can 2SCR514RTL replace BSS64 in existing PCB designs? A: 2SCR514RTL provides superior electrical performance (700 mA, 80 V, 1 W) but uses TSMT3 package instead of SOT-23-3. PCB layout modification is required. This part is suitable for new designs or redesigned boards where the enhanced current capability is beneficial.

Q: Is BSS64,215 suitable for new product development? A: BSS64,215 carries "Not For New Designs" product status. This part is restricted to legacy system maintenance and should not be selected for new development projects.

Q: What is the maximum collector current I can safely use with FMMT620TA? A: FMMT620TA is rated for 1.5 A maximum collector current at 80 V breakdown voltage. Circuit design must ensure operation within this specification and account for the 625 mW power dissipation limit under worst-case conditions.

Q: Are all substitute parts RoHS3 compliant? A: All substitute parts listed are RoHS3 compliant. Compliance status is consistent across all active and obsolete alternatives, ensuring environmental regulation adherence.

Q: What is the operating temperature range for substitute parts? A: All substitute parts operate across -55°C to 150°C junction temperature range, matching the original BSS64 specification. This ensures thermal compatibility in applications with wide operating temperature requirements.

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