BCX70H Equivalent & Substitute Parts

Part Overview

The BCX70H is an NPN bipolar junction transistor manufactured by onsemi, housed in a SOT-23-3 surface mount package. This device is rated for 45 V collector-emitter breakdown voltage with a maximum collector current of 200 mA and 350 mW power dissipation. The BCX70H is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain compatibility with the SOT-23-3 package footprint and satisfy the electrical performance requirements of the original application.

Key Parameters

Parameter	BCX70H Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	45	V
Current - Collector (Ic) (Max)	200	mA
Power - Max	350	mW
Vce Saturation (Max) @ Ib, Ic	550mV @ 1.25mA, 50mA	—
DC Current Gain (hFE) (Min) @ Ic, Vce	180 @ 2mA, 5V	—
Frequency - Transition	125	MHz
Current - Collector Cutoff (Max)	20	nA
Mounting Type	Surface Mount	—
Package / Case	SOT-23-3	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the BCX70H are selected based on the following critical parameters:

Mandatory Compatibility Criteria:

Transistor Type: NPN
Package / Case: SOT-23-3 (TO-236-3, SC-59)
Voltage - Collector Emitter Breakdown (Max): 45 V or greater
Mounting Type: Surface Mount

Performance Criteria:

Current - Collector (Ic) (Max): Equal to or greater than 200 mA
Power - Max: Equal to or greater than 350 mW
Frequency - Transition: Equal to or greater than 125 MHz

Substitute parts are grouped into two categories based on collector current rating:

Category A: Higher Current Rating (500 mA) BC817 series transistors (BC817-16LT1G, BC817-16LT3G, BC817-25LT1G, BC817-25LT3G, BC817-40LT1G, BC817-40LT3G) provide 500 mA maximum collector current, exceeding the BCX70H specification. These parts maintain the 45 V breakdown voltage and SOT-23-3 package, with reduced power dissipation (300 mW) and lower transition frequency (100 MHz). Variations within the BC817 series differ by DC current gain (hFE) rating and packaging format.

Category B: Lower Current Rating (100 mA) BC847 series transistors (BC847ALT1G, BC847BLT1G, BC847BLT3G, BC847CLT1G) provide 100 mA maximum collector current, below the BCX70H specification. These parts are suitable only for applications where the BCX70H current rating is not fully utilized. All BC847 variants maintain 45 V breakdown voltage and SOT-23-3 package compatibility.

Parameter Comparison

Parameter	BCX70H	BC817-16LT1G	BC817-25LT1G	BC817-40LT1G	BC847ALT1G	BC847BLT1G	BC847CLT1G
Transistor Type	NPN	NPN	NPN	NPN	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	45 V	45 V	45 V	45 V	45 V	45 V	45 V
Current - Collector (Ic) (Max)	200 mA	500 mA	500 mA	500 mA	100 mA	100 mA	100 mA
Power - Max	350 mW	300 mW	300 mW	300 mW	300 mW	300 mW	300 mW
Frequency - Transition	125 MHz	100 MHz	100 MHz	100 MHz	100 MHz	100 MHz	100 MHz
DC Current Gain (hFE) (Min) @ Ic, Vce	180 @ 2mA, 5V	100 @ 100mA, 1V	160 @ 100mA, 1V	250 @ 100mA, 1V	110 @ 2mA, 5V	200 @ 2mA, 5V	420 @ 2mA, 5V
Vce Saturation (Max) @ Ib, Ic	550mV @ 1.25mA, 50mA	700mV @ 50mA, 500mA	700mV @ 50mA, 500mA	700mV @ 50mA, 500mA	600mV @ 5mA, 100mA	600mV @ 5mA, 100mA	600mV @ 5mA, 100mA
Current - Collector Cutoff (Max)	20 nA	100 nA	100 nA	100 nA	15 nA	15 nA	15 nA
Package / Case	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (BC817 Series)

The BC817 series transistors are the preferred substitutes for the BCX70H in applications requiring the full 200 mA collector current specification. All BC817 variants (BC817-16LT1G, BC817-16LT3G, BC817-25LT1G, BC817-25LT3G, BC817-40LT1G, BC817-40LT3G) are classified as Active products with ROHS3 compliance, ensuring long-term availability and regulatory compliance. These parts maintain the 45 V breakdown voltage and SOT-23-3 package footprint, providing direct mechanical and electrical compatibility.

The BC817 series differs from the BCX70H in three parameters: reduced maximum power dissipation (300 mW versus 350 mW), lower transition frequency (100 MHz versus 125 MHz), and higher collector cutoff current (100 nA versus 20 nA). These differences are acceptable in most applications where the BCX70H was previously used, provided the application does not require the full 350 mW power budget or 125 MHz transition frequency.

Within the BC817 series, selection among variants is determined by DC current gain (hFE) requirements:

BC817-16 variants: hFE minimum of 100 @ 100mA, 1V
BC817-25 variants: hFE minimum of 160 @ 100mA, 1V
BC817-40 variants: hFE minimum of 250 @ 100mA, 1V

Packaging format variants (LT1G for Cut Tape & Digi-Reel, LT3G for Tape & Reel) do not affect electrical performance and are selected based on procurement and assembly requirements.

Secondary Substitutes (BC847 Series)

The BC847 series transistors are suitable substitutes only for applications where the collector current requirement does not exceed 100 mA. All BC847 variants (BC847ALT1G, BC847BLT1G, BC847BLT3G, BC847CLT1G) are classified as Active products with ROHS3 compliance. These parts maintain the 45 V breakdown voltage and SOT-23-3 package footprint.

The BC847 series differs from the BCX70H in collector current rating (100 mA versus 200 mA), power dissipation (300 mW versus 350 mW), and transition frequency (100 MHz versus 125 MHz). Additionally, BC847 variants feature lower collector cutoff current (15 nA versus 20 nA) and different DC current gain specifications measured at 2 mA collector current rather than 100 mA.

Within the BC847 series, selection is determined by DC current gain (hFE) requirements:

BC847A: hFE minimum of 110 @ 2mA, 5V
BC847B: hFE minimum of 200 @ 2mA, 5V
BC847C: hFE minimum of 420 @ 2mA, 5V

Compliance and Availability

All substitute parts listed are manufactured by onsemi and carry ROHS3 compliance certification. The BCX70H is classified as Obsolete, while all substitute parts are classified as Active, ensuring continued availability and manufacturing support. Inventory levels for substitute parts range from 10,300 to 305,400 units, indicating robust supply chain availability.

Frequently Asked Questions (FAQ)

Q: Can BC817 transistors directly replace the BCX70H without circuit modifications?

A: BC817 transistors are pin-compatible with the BCX70H in the SOT-23-3 package and maintain the same 45 V breakdown voltage. However, the reduced power dissipation (300 mW versus 350 mW) and lower transition frequency (100 MHz versus 125 MHz) must be evaluated against application requirements. If the application operates within these reduced specifications, no circuit modifications are required. If the application requires the full 350 mW power budget or 125 MHz transition frequency, circuit modifications or alternative parts must be considered.

Q: Why do BC817 variants have different part numbers (BC817-16, BC817-25, BC817-40)?

A: The numeric suffix indicates the minimum DC current gain (hFE) specification. BC817-16 specifies a minimum hFE of 100, BC817-25 specifies 160, and BC817-40 specifies 250, all measured at 100 mA collector current and 1 V collector-emitter voltage. Selection depends on the application's bias network design and required gain characteristics.

Q: Are BC847 transistors suitable replacements for the BCX70H?

A: BC847 transistors are suitable only for applications where the maximum collector current does not exceed 100 mA. The BCX70H is rated for 200 mA maximum collector current, so BC847 substitution is limited to circuits operating at half or less of the original current specification. BC847 variants are not recommended for applications requiring the full 200 mA collector current capability.

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

A: Cut Tape (CT) & Digi-Reel packaging is supplied in individual tape segments suitable for manual assembly or small-volume production. Tape & Reel (TR) packaging is supplied on continuous reels suitable for high-volume automated assembly. Both formats contain electrically identical components; selection is based on production volume and assembly equipment compatibility.

Q: Are all substitute parts RoHS compliant?

A: Yes, all substitute parts listed (BC817 and BC847 series) are ROHS3 compliant. The BCX70H product status does not specify RoHS compliance. All substitute parts carry REACH Unaffected status, indicating no restrictions under REACH regulations.

Q: What is the significance of the collector cutoff current (ICBO) difference between BCX70H and substitute parts?

A: The BCX70H specifies a maximum collector cutoff current of 20 nA, while BC817 variants specify 100 nA and BC847 variants specify 15 nA. Collector cutoff current represents leakage current when the transistor is in the off state. Higher cutoff current may affect circuit performance in applications with high impedance or precision analog circuits. For most digital and general-purpose switching applications, this difference is not significant.

Q: Can LT1G and LT3G variants of the same BC817 or BC847 part number be used interchangeably?

A: Yes, LT1G (Cut Tape & Digi-Reel) and LT3G (Tape & Reel) variants of the same base part number are electrically identical. The suffix indicates only the packaging and delivery format. Interchangeability depends on assembly process compatibility with the supplied packaging format.

Q: What is the operating temperature range for substitute parts?

A: BC817 series transistors operate from -65°C to 150°C (junction temperature). BC847 series transistors operate from -55°C to 150°C (junction temperature). The BCX70H operating temperature range is not specified in the provided data. If the application requires operation below -55°C, BC817 variants are preferred over BC847 variants.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message