2SA1774-Q-AP Equivalent & Substitute Parts

Part Overview

The 2SA1774-Q-AP is a Surface Mount PNP Bipolar Junction Transistor manufactured by Micro Commercial Co, rated for 50V collector-emitter breakdown voltage and 150mA maximum collector current. This component is classified as obsolete, necessitating identification of equivalent and substitute parts for ongoing design requirements and production continuity. The part is housed in a SOT-523 package and complies with ROHS3 standards.

Substiute Parts

2SA1774-Q-AP

Micro Commercial CoIn Stock: 10492SA1774-Q-AP Datasheet

Current PartRFQ

2DA1774Q-7-F

Diodes IncorporatedIn Stock: 363702DA1774Q-7-F Datasheet

DirectRFQ

BC857AT-7-F

Diodes IncorporatedIn Stock: 9389BC857AT-7-F Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 2SA1774-Q-AP are classified into two categories based on electrical parameter alignment:

Direct Equivalent (Electrical Match): The 2DA1774Q-7-F from Diodes Incorporated maintains identical electrical specifications across all critical parameters: 150mA maximum collector current, 50V collector-emitter breakdown voltage, 140MHz transition frequency, and 150mW maximum power dissipation. This part is functionally interchangeable within the same circuit topology and PCB layout.

Similar Substitute (Reduced Ratings): The BC857AT-7-F from Diodes Incorporated operates within reduced electrical specifications: 100mA maximum collector current (versus 150mA), 45V collector-emitter breakdown voltage (versus 50V), and 100MHz transition frequency (versus 140MHz). This part is suitable for applications where circuit requirements do not demand the full electrical performance envelope of the original part.

Substitution eligibility is determined by the following parameters:

• Transistor polarity (PNP)
• Package type (SOT-523)
• Mounting method (Surface Mount)
• Maximum power dissipation (150mW minimum)
• Operating temperature range compatibility

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement: The 2DA1774Q-7-F is the primary substitute for the obsolete 2SA1774-Q-AP. This part maintains electrical equivalence across all specified parameters and is manufactured by an active supplier (Diodes Incorporated) with current product status. Both parts comply with ROHS3 standards and share identical moisture sensitivity classification. The 2DA1774Q-7-F is available in Cut Tape packaging with significantly higher inventory availability (36,300 units in stock).

For Reduced-Specification Applications: The BC857AT-7-F serves as an alternative where circuit design margins accommodate lower maximum collector current (100mA versus 150mA), reduced collector-emitter breakdown voltage (45V versus 50V), and lower transition frequency (100MHz versus 140MHz). This part is suitable for low-power signal amplification and switching applications operating below the original part's performance envelope. The BC857AT-7-F is supplied in Tape & Reel packaging and maintains ROHS3 compliance.

Both substitute parts provide extended operating temperature range documentation (-55°C to 150°C) compared to the main part specification, offering improved thermal performance characterization for design validation.

Frequently Asked Questions (FAQ)

Q: Can the 2DA1774Q-7-F be used as a direct replacement for the 2SA1774-Q-AP without circuit modification?

A: Yes. The 2DA1774Q-7-F maintains identical electrical specifications for maximum collector current (150mA), collector-emitter breakdown voltage (50V), transition frequency (140MHz), and power dissipation (150mW). Both parts use the SOT-523 package with identical pinout and mounting requirements. No circuit redesign is required.

Q: What are the limitations of using BC857AT-7-F as a substitute?

A: The BC857AT-7-F operates at reduced electrical ratings: maximum collector current is limited to 100mA (versus 150mA), collector-emitter breakdown voltage is 45V (versus 50V), and transition frequency is 100MHz (versus 140MHz). Applications requiring the full performance envelope of the original part must use the 2DA1774Q-7-F instead.

Q: Are there packaging differences between the substitute parts?

A: The 2SA1774-Q-AP and 2DA1774Q-7-F both use SOT-523 surface mount packaging with identical mechanical specifications. The BC857AT-7-F also uses SOT-523 packaging. Packaging format differs at the supplier level: 2DA1774Q-7-F is supplied in Cut Tape, while BC857AT-7-F is supplied in Tape & Reel. PCB footprint and reflow soldering parameters remain consistent across all three parts.

Q: Do all substitute parts meet the same compliance standards?

A: Yes. The 2SA1774-Q-AP, 2DA1774Q-7-F, and BC857AT-7-F are all ROHS3 compliant with Moisture Sensitivity Level 1 (Unlimited). Both substitute parts carry REACH Unaffected status, providing regulatory alignment for international applications.

Q: What is the primary reason for substitution?

A: The 2SA1774-Q-AP is classified as obsolete. The 2DA1774Q-7-F is the recommended substitute due to active product status, electrical equivalence, and current manufacturing availability. The BC857AT-7-F provides an alternative for applications with reduced electrical requirements.

Q: How do the DC current gain specifications compare?

A: The 2SA1774-Q-AP and 2DA1774Q-7-F specify minimum DC current gain (hFE) of 120 at 1mA collector current and 6V collector-emitter voltage. The BC857AT-7-F specifies minimum hFE of 125 at 2mA collector current and 5V collector-emitter voltage. These variations reflect different measurement conditions but indicate comparable amplification characteristics.