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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi SS8550CBU

Name: SS8550CBU
Brand: onsemi
SKU: SS8550CBU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SS8550CBU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA)

Datasheet:: SS8550CBU.pdf

Description:: TRANS PNP 25V 1.5A TO-92-3

Quantity:: RFQ Add To RFQ list

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Inventory:7,179

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Product details

Overview

SS8550CBU from onsemi is a PNP epitaxial silicon transistor in TO-92-3 (case 135AN) package, rated for −25 V V_CEO, −1.5 A I_C, and 1 W power dissipation at 25°C. It delivers DC current gain (h_FE) of 120–200 at I_C = −100 mA and supports Class B push-pull audio amplifier stages in portable radios.

For engineers reviewing the SS8550CBU datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP polarity, TO-92 leadform compatibility, saturation voltage under −800 mA load, thermal resistance of 125°C/W, and h_FE classification band C.

Technical Context

This device operates as a medium-power general-purpose PNP bipolar junction transistor with complementary pairing to SS8050 (NPN). Its design targets linear amplification and switching in low-voltage DC circuits where base-driven current control and predictable saturation behavior are required.

Electrical characterization confirms operation up to 150°C junction temperature, with breakdown voltages tightly specified: −40 V V_CBO, −25 V V_CEO, and −6 V V_EBO. The 100–200 MHz f_T enables use in audio-frequency amplifiers and low-speed switching applications.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−25 V: Maximum allowable collector-emitter voltage before avalanche breakdown in common-emitter configuration.
I_C	−1.5 A: Continuous DC collector current rating; defines maximum sustained load-handling capability.
P_D	1 W at T_A = 25°C: Power dissipation limit on standard FR-4 PCB; derates 8 mW/°C above ambient.
h_FE (I_C = −100 mA)	120–200: Confirmed DC current gain range for Class C h_FE bin; ensures consistent base drive requirements across production lots.
V_CE(sat)	−0.28 to −0.50 V at I_C = −800 mA, I_B = −80 mA: Low saturation voltage enables efficient switching with minimal conduction loss.
f_T	100–200 MHz: Current gain-bandwidth product confirming suitability for audio amplification and low-MHz signal handling.

Pinout & Package

SS8550CBU uses the TO-92-3 package (case 135AN), with standardized leadform: emitter (pin 1), base (pin 2), collector (pin 3), viewed from flat side with leads down.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit terminal for PNP operation	Connected to higher potential rail in common-emitter switch or amplifier configurations.
2 (Base)	Control input for minority-carrier injection	Requires negative bias relative to emitter to forward-bias base-emitter junction and enable conduction.
3 (Collector)	Current entry terminal for PNP operation	Typically tied to ground or low-side return path; carries load current into device.

Key Features

Feature	Design Value
Complementary pairing	Matched performance with NPN SS8050 for push-pull amplifier stages without redesign.
RoHS-compliant construction	Pb-free, halogen-free/BFR-free materials meet global environmental compliance requirements.
Class C h_FE binning	Guaranteed h_FE of 120–200 at I_C = −100 mA enables predictable base resistor sizing.
Low V_CE(sat)	−0.28 V minimum reduces power loss during saturated switching in battery-powered systems.

Applications

Portable Audio Amplifiers	DC Motor Drivers
Use Scenario: Class B push-pull output stage in AM/FM portable radios and small speaker drivers. IC Role / Device Role / Timing Role: PNP transistor providing half-cycle amplification complementing NPN SS8050. Use Value: Delivers 2 W amplifier output with matched h_FE and V_CE(sat) to minimize crossover distortion.	Use Scenario: Low-side driver for 12 V brushed DC motors in toys and small actuators. IC Role / Device Role / Timing Role: Switching element controlling motor current flow via base-triggered saturation. Use Value: −0.28 V V_CE(sat) limits conduction loss at 800 mA, extending battery life in intermittent-duty applications.
LED Constant-Current Sources	Power Supply Pass Transistors
Use Scenario: Emitter-follower configured constant-current sink for high-brightness LED strings. IC Role / Device Role / Timing Role: Linear regulator element maintaining stable LED current despite supply variation. Use Value: Tight h_FE bin (120–200) ensures repeatable current setting with fixed base resistor networks.	Use Scenario: Series pass element in linear voltage regulators delivering ≤12 V at ≤1 A. IC Role / Device Role / Timing Role: Adjustable current source regulating output voltage via feedback-controlled base bias. Use Value: 150°C max junction temperature and 125°C/W R_JA support thermally constrained board layouts.

Portable Audio Amplifiers

DC Motor Drivers

Use Scenario: Class B push-pull output stage in AM/FM portable radios and small speaker drivers.

IC Role / Device Role / Timing Role: PNP transistor providing half-cycle amplification complementing NPN SS8050.

Use Value: Delivers 2 W amplifier output with matched h_FE and V_CE(sat) to minimize crossover distortion.

Use Scenario: Low-side driver for 12 V brushed DC motors in toys and small actuators.

IC Role / Device Role / Timing Role: Switching element controlling motor current flow via base-triggered saturation.

Use Value: −0.28 V V_CE(sat) limits conduction loss at 800 mA, extending battery life in intermittent-duty applications.

LED Constant-Current Sources

Power Supply Pass Transistors

Use Scenario: Emitter-follower configured constant-current sink for high-brightness LED strings.

IC Role / Device Role / Timing Role: Linear regulator element maintaining stable LED current despite supply variation.

Use Value: Tight h_FE bin (120–200) ensures repeatable current setting with fixed base resistor networks.

Use Scenario: Series pass element in linear voltage regulators delivering ≤12 V at ≤1 A.

IC Role / Device Role / Timing Role: Adjustable current source regulating output voltage via feedback-controlled base bias.

Use Value: 150°C max junction temperature and 125°C/W R_JA support thermally constrained board layouts.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SS8550DBU	Same TO-92-3 package; h_FE bin D (160–300) instead of C (120–200).	Higher gain enables reduced base drive current but may increase sensitivity to thermal drift.	Select SS8550DBU when tighter base-current control is needed and circuit tolerates wider h_FE spread.
MPSA92	Higher V_CEO (−300 V), lower I_C (−500 mA), TO-92 package; not pin-compatible.	Suitable for high-voltage, low-current switching (e.g., CRT deflection, relay drivers), not audio amplification.	Choose MPSA92 only for high-V_CEO requirements; verify layout changes due to different pinout and gain profile.

Compared with SS8550DBU and MPSA92, the SS8550CBU offers balanced gain (120–200), proven audio-class linearity, and direct mechanical compatibility with SS8050 in push-pull designs-making it optimal for cost-sensitive, medium-power PNP switching and amplification where predictable h_FE and low V_CE(sat) are critical.

Availability

SS8550CBU is available at Aetrix Electronics and suitable for portable audio amplifiers, DC motor drivers, and LED constant-current sources requiring stable component supply and RoHS-compliant manufacturing.

Supply support for SS8550CBU includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, serving automotive, industrial, cloud, and consumer markets with discrete, analog, and logic solutions.

The SS8550CBU belongs to onsemi's general-purpose bipolar transistor product line, engineered for reliable, low-cost amplification and switching in battery-powered and space-constrained applications.

FAQ

What is the pin configuration of the SS8550CBU?

The SS8550CBU uses a TO-92-3 package with emitter (pin 1), base (pin 2), and collector (pin 3) - identified when viewing the flat side of the package with leads pointing downward. This configuration matches industry-standard PNP TO-92 orientation and is confirmed in the official onsemi datasheet (document SS8550/D, Rev. 3).

Is SS8550CBU RoHS compliant?

Yes, the SS8550CBU is explicitly marked Pb-free, halogen-free/BFR-free, and RoHS compliant per onsemi's datasheet (SS8550/D, Rev. 3). Compliance is verified through material declarations and manufacturing process controls, making it suitable for environmentally regulated end products.

What is the maximum operating junction temperature for SS8550CBU?

The SS8550CBU has a maximum junction temperature (T_J) of 150°C, as specified in the Absolute Maximum Ratings table of its datasheet. This rating allows operation in thermally demanding environments when combined with appropriate PCB copper area and airflow, assuming thermal resistance (R_JA) remains at 125°C/W.

How does SS8550CBU differ from SS8550DBU?

The SS8550CBU and SS8550DBU share identical package (TO-92-3, case 135AN), voltage/current ratings, and RoHS compliance-but differ in h_FE binning: SS8550CBU is Class C (120–200), while SS8550DBU is Class D (160–300). This affects base drive design but not pinout or thermal behavior.

Can SS8550CBU replace BC557 in existing designs?

SS8550CBU is not a direct replacement for BC557: BC557 uses TO-92 but has different h_FE range (125–800), higher V_CEO (−45 V), and distinct saturation characteristics. While both are PNP transistors, substituting SS8550CBU requires validation of gain matching, thermal margin, and V_CE(sat) impact on circuit performance.

SS8550CBU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA)

Packaging:: Bulk

Product Status:: Active

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 1.5 A

Voltage - Collector Emitter Breakdown (Max):: 25 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 80mA, 800mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 120 @ 100mA, 1V

Power - Max:: 1 W

Frequency - Transition:: 200MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

SS8550CBU FAQ

1.How can I place an order for SS8550CBU through Aetrix?

Please submit a Request for Quotation (RFQ) for SS8550CBU on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for SS8550CBU reliable?

The price and inventory of SS8550CBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SS8550CBU is usually 5 days.

3.What payment methods are accepted for SS8550CBU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SS8550CBU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SS8550CBU?

SS8550CBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SS8550CBU order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for SS8550CBU?

For technical support, including SS8550CBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SS8550CBU requirements.

6.How does Aetrix verify that SS8550CBU is sourced from the original manufacturer or authorized distributors?

All SS8550CBU products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SS8550CBU meets industry standards.

7.What is the process for return or replacement of SS8550CBU?

All SS8550CBU units undergo pre-shipment inspection (PSI). If there is an issue with SS8550CBU, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The SS8550CBU part is unused and in its original packaging.

Return procedure for SS8550CBU:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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