CMPTA42 TR NPN Bipolar Junction Transistor Equivalent & Substitute Parts

Part Overview

The CMPTA42 TR is an NPN bipolar junction transistor manufactured by Central Semiconductor Corp, designed for general-purpose switching and amplification applications. This surface mount device operates at 300 V collector-emitter breakdown voltage with a maximum collector current of 500 mA and 350 mW power dissipation. The part is packaged in SOT-23 (TO-236-3) configuration and is currently in active production status with 660 pieces in stock.

Equivalent and substitute parts are necessary when the primary part becomes unavailable, when alternative sourcing is required for supply chain resilience, or when design specifications allow for components with enhanced electrical characteristics within the same functional category.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	300	V
Current - Collector (Ic) (Max)	500	mA
Power - Max	350	mW
Frequency - Transition	50	MHz
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 30mA, 10V	—
Vce Saturation (Max) @ Ib, Ic	500mV @ 2mA, 20mA	—
Current - Collector Cutoff (Max)	100	nA
Operating Temperature Range	-65 to 150	°C
Package / Case	SOT-23-3 (TO-236-3, SC-59)	—
Mounting Type	Surface Mount	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the CMPTA42 TR is determined by strict electrical and mechanical compatibility within the NPN bipolar junction transistor category. The following parameters establish the substitution criteria:

Primary Compatibility Parameters:

Transistor type must be NPN
Collector-emitter breakdown voltage must be greater than or equal to 300 V
Maximum collector current must be greater than or equal to 500 mA
Maximum power dissipation must be greater than or equal to 350 mW
Package must be SOT-23 or equivalent surface mount configuration (TO-236-3, SC-59, SOT-23-3)
DC current gain (hFE) minimum at specified conditions must be compatible with circuit design requirements
Operating temperature range must encompass the application requirements

Secondary Compatibility Parameters:

Vce saturation characteristics
Collector cutoff current (ICBO)
Transition frequency (fT)
Moisture sensitivity level

Substitute parts are grouped into two categories: Direct Equivalents (matching all primary parameters within tolerance) and Enhanced Substitutes (exceeding one or more electrical specifications while maintaining functional compatibility).

Parameter Comparison

Part Number	Manufacturer	Vce(BR)max (V)	Ic(Max) (mA)	P(Max) (mW)	fT (MHz)	hFE(Min) @ Ic, Vce	Vce(Sat) @ Ib, Ic	Package	Status
CMPTA42 TR	Central Semiconductor Corp	300	500	350	50	40 @ 30mA, 10V	500mV @ 2mA, 20mA	SOT-23	Active
CMPTA42E TR PBFREE	Central Semiconductor Corp	350	500	350	75	50 @ 30mA, 10V	350mV @ 5mA, 50mA	SOT-23	Active
FJV42MTF	onsemi	350	500	350	50	40 @ 30mA, 10V	500mV @ 2mA, 20mA	SOT-23-3	Active
MMBTA42-7-F	Diodes Incorporated	300	500	300	50	40 @ 30mA, 10V	500mV @ 2mA, 20mA	SOT-23-3	Active
PBHV8540T,215	Nexperia USA Inc.	400	500	300	30	10 @ 300mA, 10V	250mV @ 60mA, 300mA	TO-236AB	Active
SMBTA42E6327HTSA1	Infineon Technologies	300	500	360	70	40 @ 30mA, 10V	500mV @ 2mA, 20mA	PG-SOT23	Last Time Buy
SMMBTA42LT1G	onsemi	300	500	225	50	40 @ 30mA, 10V	500mV @ 2mA, 20mA	SOT-23-3	Active
SMMBTA42LT3G	onsemi	300	500	225	50	40 @ 30mA, 10V	500mV @ 2mA, 20mA	SOT-23-3	Active
TSC497CX RFG	Taiwan Semiconductor Corporation	300	500	500	75	100 @ 1mA, 10V	300mV @ 25mA, 250mA	SOT-23	Active

Engineering Selection Recommendations

Category 1: Direct Electrical Equivalents

MMBTA42-7-F (Diodes Incorporated) and SMMBTA42LT1G / SMMBTA42LT3G (onsemi) provide direct functional equivalence to the CMPTA42 TR. These parts maintain identical collector-emitter breakdown voltage (300 V), collector current (500 mA), DC current gain characteristics, and saturation voltage specifications. All three parts are in active production status with ROHS3 compliance. SMMBTA42LT1G carries AEC-Q101 automotive qualification, suitable for applications requiring automotive-grade reliability.

Category 2: Enhanced Voltage Rating Substitutes

CMPTA42E TR PBFREE (Central Semiconductor Corp) and FJV42MTF (onsemi) offer increased collector-emitter breakdown voltage (350 V) while maintaining all other primary electrical parameters. These parts are suitable for applications where higher voltage margin is beneficial. CMPTA42E TR PBFREE provides the same manufacturer lineage as the primary part with enhanced specifications and ROHS3 compliance. FJV42MTF offers equivalent performance with high inventory availability (125,400 pieces).

Category 3: High-Voltage Substitute

PBHV8540T,215 (Nexperia USA Inc.) provides the highest collector-emitter breakdown voltage (400 V) among available substitutes. This part is suitable for applications requiring maximum voltage headroom. Note that this part exhibits lower DC current gain (10 @ 300mA, 10V) and reduced transition frequency (30 MHz) compared to the primary part, requiring circuit-level evaluation for compatibility.

Category 4: Enhanced Power Dissipation Substitutes

TSC497CX RFG (Taiwan Semiconductor Corporation) offers the highest power dissipation rating (500 mW) and transition frequency (75 MHz), with significantly higher DC current gain (100 @ 1mA, 10V). This part is suitable for applications requiring enhanced thermal performance or higher-frequency operation. SMBTA42E6327HTSA1 (Infineon Technologies) provides 360 mW power rating with 70 MHz transition frequency, though it carries Last Time Buy status.

Compliance and Production Status:

All recommended substitutes maintain ROHS3 compliance and REACH unaffected status. All parts carry MSL 1 (Unlimited) moisture sensitivity rating. Selection should prioritize parts with Active production status: CMPTA42E TR PBFREE, FJV42MTF, MMBTA42-7-F, PBHV8540T,215, SMMBTA42LT1G, SMMBTA42LT3G, and TSC497CX RFG.

Frequently Asked Questions (FAQ)

Q1: Can SMMBTA42LT1G replace CMPTA42 TR in all applications?

SMMBTA42LT1G is electrically equivalent to CMPTA42 TR with identical voltage, current, and gain specifications. The primary difference is reduced maximum power dissipation (225 mW vs. 350 mW). Substitution is valid for applications where power dissipation does not exceed 225 mW. SMMBTA42LT1G carries AEC-Q101 automotive qualification, making it suitable for automotive applications where CMPTA42 TR may not be qualified.

Q2: What is the difference between CMPTA42E TR PBFREE and CMPTA42 TR?

CMPTA42E TR PBFREE is an enhanced version of CMPTA42 TR with increased collector-emitter breakdown voltage (350 V vs. 300 V), higher transition frequency (75 MHz vs. 50 MHz), and improved saturation voltage characteristics (350 mV vs. 500 mV at specified conditions). Both parts maintain identical collector current (500 mA) and power dissipation (350 mW). CMPTA42E TR PBFREE is a direct upgrade suitable for all applications where CMPTA42 TR is used, with the added benefit of higher voltage margin.

Q3: Is PBHV8540T,215 suitable as a direct replacement for CMPTA42 TR?

PBHV8540T,215 provides higher collector-emitter breakdown voltage (400 V) and identical collector current (500 mA), making it mechanically and functionally compatible. However, this part exhibits significantly lower DC current gain (10 @ 300mA, 10V vs. 40 @ 30mA, 10V) and reduced transition frequency (30 MHz vs. 50 MHz). Circuit-level evaluation is required to confirm compatibility, particularly for applications sensitive to current gain or frequency response.

Q4: Can SMMBTA42LT1G and SMMBTA42LT3G be used interchangeably?

SMMBTA42LT1G and SMMBTA42LT3G are electrically identical with identical electrical specifications. The primary difference is packaging: SMMBTA42LT1G is supplied in Cut Tape (CT) & Digi-Reel format, while SMMBTA42LT3G is supplied in Tape & Reel (TR) format. Selection depends on assembly process requirements and tape reel specifications rather than electrical performance.

Q5: What is the significance of the operating temperature range difference between CMPTA42 TR (-65°C to 150°C) and MMBTA42-7-F (-55°C to 150°C)?

CMPTA42 TR specifies a lower minimum operating temperature (-65°C) compared to MMBTA42-7-F (-55°C). For applications requiring operation below -55°C, CMPTA42 TR or SMMBTA42LT1G / SMMBTA42LT3G (both -55°C to 150°C) must be used. For applications within the -55°C to 150°C range, MMBTA42-7-F is fully compatible.

Q6: Why does TSC497CX RFG have higher DC current gain than CMPTA42 TR?

TSC497CX RFG exhibits DC current gain of 100 @ 1mA, 10V compared to CMPTA42 TR's 40 @ 30mA, 10V. These specifications are measured at different collector current levels (1 mA vs. 30 mA), making direct comparison inappropriate. At equivalent measurement conditions, the parts would exhibit comparable gain characteristics. TSC497CX RFG's higher power dissipation (500 mW) and transition frequency (75 MHz) make it suitable for higher-performance applications.

Q7: Are all substitute parts ROHS3 compliant?

All recommended substitute parts carry ROHS3 compliance status. CMPTA42 TR does not specify ROHS3 compliance in the provided data. If ROHS3 compliance is a design requirement, CMPTA42E TR PBFREE, FJV42MTF, MMBTA42-7-F, PBHV8540T,215, SMBTA42E6327HTSA1, SMMBTA42LT1G, SMMBTA42LT3G, and TSC497CX RFG all meet this requirement.

Q8: What packaging considerations apply when substituting CMPTA42 TR?

CMPTA42 TR is supplied in Tape & Reel (TR) format in SOT-23 package. Most substitute parts are available in SOT-23-3 or equivalent configurations. Verify that the selected substitute part's package specification (SOT-23, SOT-23-3, TO-236-3, SC-59, or TO-236AB) is compatible with PCB footprint and assembly equipment. Packaging format (Cut Tape, Tape & Reel, or Digi-Reel) affects supply chain logistics but not electrical performance.

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