8550SS-D-AP Equivalent & Substitute Parts

Part Overview

The 8550SS-D-AP is a PNP bipolar junction transistor manufactured by Micro Commercial Co, rated for 25 V collector-emitter breakdown voltage and 1.5 A maximum collector current. This device is packaged in a TO-92 through-hole configuration and is designed for small-signal switching and amplification applications. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility for ongoing production and repair applications.

Substiute Parts

8550SS-D-AP

Micro Commercial CoIn Stock: 6708550SS-D-AP Datasheet

Current PartRFQ

SS8550CTA

Fairchild SemiconductorIn Stock: 41321SS8550CTA Datasheet

MFR RecommendedRFQ

SS8550DTA

onsemiIn Stock: 45141SS8550DTA Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 8550SS-D-AP is determined by strict equivalence across the following electrical and mechanical parameters:

Critical Matching Parameters:

• Transistor polarity: PNP
• Maximum collector current: 1.5 A
• Maximum collector-emitter breakdown voltage: 25 V
• Saturation voltage characteristics: 500mV @ 80mA, 800mA
• Maximum collector cutoff current: 100nA
• Package type: TO-92-3 through-hole configuration
• Mounting method: Through-hole

Acceptable Variation Parameters:

• Transition frequency: Equal to or greater than 100MHz
• DC current gain (hFE): Equal to or greater than 120 @ 100mA, 1V
• Maximum operating temperature: Equal to or greater than 150°C
• Product status: Active preferred for ongoing availability

Both substitute parts (SS8550CTA and SS8550DTA) meet all critical matching parameters and exceed acceptable variation thresholds, enabling direct functional replacement in circuit applications.

Parameter Comparison

Engineering Selection Recommendations

SS8550CTA (Fairchild Semiconductor) is suitable for applications requiring active product status and standard RoHS compliance. This device provides transition frequency of 200MHz, exceeding the original specification, with DC current gain of 120 @ 100mA, 1V, which is within acceptable operating margins for most circuit designs. Bulk packaging is available for high-volume procurement.

SS8550DTA (onsemi) is suitable for applications requiring active product status with enhanced compliance documentation. This device maintains the original DC current gain specification of 160 @ 100mA, 1V and provides transition frequency of 200MHz. ROHS3 compliance and REACH unaffected status support regulatory requirements for restricted substance management. Cut tape packaging is available for automated assembly processes.

Both substitutes eliminate obsolescence risk while maintaining full electrical and mechanical compatibility with the original 8550SS-D-AP design. Selection between SS8550CTA and SS8550DTA depends on packaging requirements (bulk versus cut tape) and compliance documentation needs.

Frequently Asked Questions (FAQ)

Q: Can SS8550CTA and SS8550DTA be used interchangeably with 8550SS-D-AP in existing circuit designs?

A: Yes. Both substitute parts meet all critical electrical parameters including collector current rating (1.5 A), breakdown voltage (25 V), saturation voltage characteristics, and package configuration (TO-92-3 through-hole). Direct pin-for-pin replacement is supported without circuit modification.

Q: What is the significance of the higher transition frequency (200MHz) in the substitute parts compared to the original 100MHz specification?

A: The higher transition frequency indicates improved high-frequency performance capability. This parameter represents the frequency at which current gain drops to unity. Substitutes with higher transition frequency maintain or exceed the original device performance envelope and do not introduce incompatibility in applications designed for 100MHz operation.

Q: How do the DC current gain differences between SS8550CTA (120) and SS8550DTA (160) affect circuit performance?

A: DC current gain (hFE) determines the amplification factor in transistor circuits. SS8550DTA matches the original specification of 160, while SS8550CTA provides 120. Both values exceed minimum acceptable thresholds for standard small-signal applications. Circuit designs using the original 8550SS-D-AP with hFE of 160 will experience identical performance with SS8550DTA. Designs using SS8550CTA may require base current adjustment in precision applications, though saturation voltage characteristics remain identical.

Q: What packaging differences exist between SS8550CTA and SS8550DTA?

A: SS8550CTA is supplied in bulk packaging, suitable for manual assembly and stocking. SS8550DTA is supplied in cut tape (CT) packaging, optimized for automated pick-and-place assembly processes. Both use identical TO-92-3 component geometry and are mechanically interchangeable.

Q: Are there compliance or regulatory differences between the substitute parts?

A: SS8550DTA provides ROHS3 compliance and REACH unaffected status documentation. SS8550CTA compliance status is not specified in available data. For applications requiring documented ROHS3 compliance, SS8550DTA is the appropriate selection.

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

A: Both SS8550CTA and SS8550DTA specify maximum junction temperature of 150°C. The original 8550SS-D-AP specifies operating range of -55°C to 150°C. Substitute parts are rated to the same maximum temperature. Minimum operating temperature specifications for the substitutes are not provided; applications requiring operation below -55°C require verification against detailed datasheets.