2SA844-E-AP Equivalent & Substitute Parts

Part Overview

The 2SA844-E-AP is a PNP bipolar junction transistor manufactured by Micro Commercial Co, housed in a TO-92 through-hole package. This component is rated for 55 V collector-emitter breakdown voltage, 100 mA maximum collector current, and 300 mW power dissipation. The device operates at a transition frequency of 200 MHz with a maximum junction temperature of 150°C.

The 2SA844-E-AP is classified as obsolete. Substitute parts are necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Substiute Parts

2SA844-E-AP

Micro Commercial CoIn Stock: 6892SA844-E-AP Datasheet

Current PartRFQ

BC556BTA

Fairchild SemiconductorIn Stock: 18331BC556BTA Datasheet

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BC557ATA

Fairchild SemiconductorIn Stock: 860BC557ATA Datasheet

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BC557BTA

onsemiIn Stock: 6210BC557BTA Datasheet

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BC557BTF

onsemiIn Stock: 41658BC557BTF Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 2SA844-E-AP is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

• Transistor type must be PNP
• Collector current rating must equal or exceed 100 mA
• Collector-emitter breakdown voltage must equal or exceed 55 V
• Power dissipation must equal or exceed 300 mW
• Operating temperature range must support 150°C maximum junction temperature
• Package and mounting type must be TO-92-3 through-hole configuration

Substitute parts BC556BTA, BC557ATA, BC557BTA, and BC557BTF meet the mechanical package requirement (TO-92-3 through-hole) and share the same collector current rating (100 mA) and operating temperature maximum (150°C). However, electrical parameter variations exist across the substitute group and must be evaluated against specific application requirements.

Parameter Comparison

Engineering Selection Recommendations

BC556BTA (Fairchild Semiconductor): This substitute provides the highest collector-emitter breakdown voltage rating (65 V) among available options, exceeding the 2SA844-E-AP specification of 55 V. Power dissipation is increased to 500 mW. Transition frequency is reduced to 150 MHz. Product status is active with current availability. RoHS3 compliance status is not specified in provided data.

BC557ATA (Fairchild Semiconductor): This substitute operates at a reduced collector-emitter breakdown voltage of 45 V, which is below the 2SA844-E-AP rating of 55 V. Power dissipation is increased to 500 mW. Transition frequency is 150 MHz. Product status is active. RoHS3 compliance status is not specified in provided data.

BC557BTA (onsemi): This substitute operates at a collector-emitter breakdown voltage of 45 V, below the 2SA844-E-AP specification. Power dissipation is 500 mW. Transition frequency is 150 MHz. Product status is active with RoHS3 compliance confirmed. Moisture sensitivity level is not applicable.

BC557BTF (onsemi): This substitute operates at a collector-emitter breakdown voltage of 45 V, below the 2SA844-E-AP specification. Power dissipation is 500 mW. Transition frequency is 150 MHz. Product status is active with RoHS3 compliance confirmed. Moisture sensitivity level is not applicable. Highest inventory availability among substitutes (41,626 pcs).

Selection between substitute parts depends on application voltage requirements. Applications operating at or below 45 V may use BC557ATA, BC557BTA, or BC557BTF. Applications requiring voltage headroom above 45 V but within 55 V should use BC556BTA. All substitutes maintain TO-92-3 package compatibility and 100 mA collector current rating.

Frequently Asked Questions (FAQ)

Q: Can BC557ATA, BC557BTA, or BC557BTF be used in applications designed for the 2SA844-E-AP?

A: These substitutes are compatible only in applications where the maximum supply voltage does not exceed 45 V. The 2SA844-E-AP is rated for 55 V collector-emitter breakdown voltage. Using a 45 V rated substitute in a 55 V application creates risk of device failure. BC556BTA is suitable for applications requiring the full 55 V rating.

Q: What is the impact of reduced transition frequency in substitute parts?

A: The 2SA844-E-AP operates at 200 MHz transition frequency. All substitute parts operate at 150 MHz. In applications where switching speed is critical, this 25% reduction in transition frequency may affect circuit performance. Applications with lower frequency requirements are unaffected.

Q: Are all substitute parts available in the same package configuration?

A: Yes. All substitute parts use the TO-92-3 through-hole package with formed leads, identical to the 2SA844-E-AP. Pin configuration and physical dimensions are compatible for direct board-level replacement.

Q: Which substitute part offers the best compliance and availability?

A: BC557BTF (onsemi) provides RoHS3 compliance confirmation, active product status, and the highest inventory availability at 41,626 pieces. BC557BTA (onsemi) also provides RoHS3 compliance with 6,200 pieces in stock. Both are suitable for new designs requiring regulatory compliance.

Q: Can BC556BTA be used as a universal replacement for the 2SA844-E-AP?

A: BC556BTA is suitable for applications operating at voltages up to 65 V, which exceeds the 2SA844-E-AP specification of 55 V. This provides additional voltage margin. However, RoHS3 compliance status is not specified for BC556BTA in provided data. Verify compliance requirements before selection.

Q: What are the DC current gain differences between the main part and substitutes?

A: The 2SA844-E-AP specifies minimum DC current gain (hFE) of 400 at 2 mA collector current and 12 V collector-emitter voltage. Substitute parts specify hFE values between 110 and 200 at different test conditions (2 mA, 5 V). These differences reflect different measurement conditions and device grades. Verify DC current gain requirements for specific circuit applications.