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

onsemi 2SA1318S-AA

Name: 2SA1318S-AA
Brand: onsemi
SKU: 2SA1318S-AA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SA1318S-AA

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: 2SA1318S-AA.pdf

Description:: TRANS PNP 50V 0.2A 3-NP

Quantity:: RFQ Add To RFQ list

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Inventory:18,000

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Product details

Overview

2SA1318S-AA from ON Semiconductor is a PNP epitaxial planar silicon transistor designed for audio frequency amplification, with V_CEO = −50 V, I_C = −150 mA, h_FE = 70–140 at I_C = −2 mA, and f_T = 80 MHz. It serves as a low-noise preamplifier stage in discrete AF amplifier circuits.

For engineers reviewing the 2SA1318S-AA datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain linearity at low collector currents, safe operating area under Class-A bias, and complementary pairing capability with NPN 2SC3331 for push-pull output stages.

Technical Context

The 2SA1318S-AA employs an epitaxial planar structure to achieve stable h_FE across temperature and consistent V_CE(sat) ≤ −0.5 V at I_C = −100 mA and I_B = −10 mA. Its f_T of 80 MHz supports wideband AF response up to 20 kHz with margin.

Designed for linear operation, it features tight h_FE grouping (70–140) and low noise figure (NF ≈ 10 dB at 1 kHz, R_S = 1 kΩ), enabling use in high-fidelity preamp inputs where signal integrity is critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−50 V: Maximum reverse-biased collector–emitter voltage before breakdown; sets rail limit for single-supply AF stages.
I_C (max)	−150 mA: Continuous collector current rating; supports medium-power Class-A driver stages.
h_FE	70–140 at I_C = −2 mA: DC current gain range ensures predictable bias stability in fixed-bias or emitter-degenerated topologies.
f_T	80 MHz: Transition frequency confirms adequate gain-bandwidth for full-audio-spectrum amplification with headroom.
V_CE(sat)	≤ −0.5 V at I_C = −100 mA, I_B = −10 mA: Low saturation voltage minimizes power loss and thermal rise in output buffer roles.
NF	≈10 dB at 1 kHz, R_S = 1 kΩ: Confirmed noise performance enables use in first-stage preamplifiers without degrading SNR.

Pinout & Package

2SA1318S-AA is housed in a TO-92MOD plastic package with lead-free finish and JEDEC-standard footprint. Pin assignment follows EBC (Emitter–Base–Collector) configuration when viewed with flat side facing user and leads downward.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal	Connected to ground or negative rail in common-emitter AF amps; defines reference for bias network.
Base (B)	Control input	Receives forward-biased current to modulate collector current; requires series resistor for stable DC biasing.
Collector (C)	Output current source	Drives load or next stage; polarity reversal vs. NPN mandates inverted supply topology in complementary designs.

Key Features

Feature	Design Value
Complementary pair with 2SC3331	Enables matched push-pull output stages without gain or thermal mismatch penalties.
Tight h_FE grouping (70–140)	Reduces need for individual bias trimming in production audio equipment.
Low noise figure (≈10 dB)	Preserves dynamic range in microphone preamplifiers and phono stages.
TO-92MOD package	Supports manual assembly and wave soldering while maintaining thermal resistance of ~200°C/W.

Applications

High-Fidelity Preamplifier	Discrete Tone Control Stage
Use Scenario: First amplification stage in a vinyl record playback system handling mV-level signals from moving-magnet cartridges. IC Role / Device Role / Timing Role: PNP transistor configured in common-emitter topology to provide voltage gain with minimal added noise. Use Value: Low NF ≈10 dB and stable h_FE ensure accurate signal reproduction without coloration or distortion.	Use Scenario: Active equalization circuit shaping bass/mid/treble bands using feedback networks around discrete transistors. IC Role / Device Role / Timing Role: Gain-setting element in buffered active filter sections requiring linear small-signal behavior. Use Value: Tight h_FE tolerance and low V_CE(sat) maintain filter Q-factor accuracy and prevent gain droop at band edges.
Class-A Headphone Driver	Push-Pull Output Stage
Use Scenario: Single-ended headphone amplifier delivering 30 mW into 32 Ω loads with zero crossover distortion. IC Role / Device Role / Timing Role: Linearly biased PNP output device operating in Class-A mode with constant collector current. Use Value: V_CEO = −50 V and I_C = −150 mA support safe operation at ±12 V rails with thermal margin.	Use Scenario: Complementary output pair driving 8 Ω loudspeaker loads in compact audio modules. IC Role / Device Role / Timing Role: PNP half of matched 2SA1318S-AA / 2SC3331 pair delivering symmetrical positive/negative swing. Use Value: Matched f_T and h_FE minimize even-order harmonic distortion and improve THD+N below 0.5%.

High-Fidelity Preamplifier

Discrete Tone Control Stage

Use Scenario: First amplification stage in a vinyl record playback system handling mV-level signals from moving-magnet cartridges.

IC Role / Device Role / Timing Role: PNP transistor configured in common-emitter topology to provide voltage gain with minimal added noise.

Use Value: Low NF ≈10 dB and stable h_FE ensure accurate signal reproduction without coloration or distortion.

Use Scenario: Active equalization circuit shaping bass/mid/treble bands using feedback networks around discrete transistors.

IC Role / Device Role / Timing Role: Gain-setting element in buffered active filter sections requiring linear small-signal behavior.

Use Value: Tight h_FE tolerance and low V_CE(sat) maintain filter Q-factor accuracy and prevent gain droop at band edges.

Class-A Headphone Driver

Push-Pull Output Stage

Use Scenario: Single-ended headphone amplifier delivering 30 mW into 32 Ω loads with zero crossover distortion.

IC Role / Device Role / Timing Role: Linearly biased PNP output device operating in Class-A mode with constant collector current.

Use Value: V_CEO = −50 V and I_C = −150 mA support safe operation at ±12 V rails with thermal margin.

Use Scenario: Complementary output pair driving 8 Ω loudspeaker loads in compact audio modules.

IC Role / Device Role / Timing Role: PNP half of matched 2SA1318S-AA / 2SC3331 pair delivering symmetrical positive/negative swing.

Use Value: Matched f_T and h_FE minimize even-order harmonic distortion and improve THD+N below 0.5%.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SA1015BL	V_CEO = −50 V, h_FE = 120–240, f_T = 80 MHz, TO-92 package	Higher h_FE range increases sensitivity to thermal runaway in fixed-bias designs	Preferable where higher gain is needed and emitter degeneration is used for stabilization.
KSA708YTA	V_CEO = −60 V, I_C = −100 mA, h_FE = 100–200, TO-92	Lower I_C rating limits output power capability in driver roles	Suitable for preamp stages but not recommended for >20 mW output buffering without derating.

Compared with 2SA1318S-AA, 2SA1015BL offers higher gain at the cost of tighter thermal management, while KSA708YTA provides greater voltage margin but reduced current drive-making 2SA1318S-AA optimal for balanced AF gain and power delivery in compact designs.

Availability

2SA1318S-AA is available at Aetrix Electronics and suitable for high-fidelity preamplifiers, discrete tone control circuits, and Class-A headphone drivers requiring stable component supply and consistent h_FE matching.

Supply support for 2SA1318S-AA 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

ON Semiconductor is a global semiconductor supplier focused on energy-efficient electronics, delivering discrete, analog, and logic solutions for automotive, industrial, and consumer markets.

The 2SA1318S-AA belongs to ON Semiconductor's legacy audio transistor product line, engineered specifically for high-linearity, low-noise analog signal amplification in discrete amplifier topologies.

FAQ

What is the maximum collector–emitter voltage rating for the 2SA1318S-AA?

The 2SA1318S-AA has a guaranteed V_CEO rating of −50 V. This specifies the maximum reverse-biased voltage the transistor can withstand between collector and emitter with the base open. Exceeding this value risks avalanche breakdown and permanent damage. Designers must ensure supply rails and signal swings remain within this limit, especially in transformer-coupled or capacitive-coupled AF stages.

Is the 2SA1318S-AA pin-compatible with the 2SC3331 NPN transistor?

Yes-the 2SA1318S-AA and 2SC3331 share identical TO-92MOD packages and EBC (Emitter–Base–Collector) pinout orientation. This allows direct physical placement as complementary pairs on PCBs without layout changes. Their matched f_T, h_FE ranges, and thermal characteristics further support symmetrical push-pull operation in discrete amplifier designs.

What is the typical noise figure of the 2SA1318S-AA and under what conditions is it measured?

The 2SA1318S-AA exhibits a typical noise figure (NF) of ≈10 dB at 1 kHz with a source resistance (R_S) of 1 kΩ. This value is measured under standardized small-signal AC conditions per ON Semiconductor's official datasheet. It reflects the transistor's contribution to signal degradation in low-level preamplifier applications, making it suitable for phono and microphone input stages.

Can the 2SA1318S-AA be used in switching applications?

The 2SA1318S-AA is optimized for linear AF amplification-not fast switching. Its f_T of 80 MHz and moderate V_CE(sat) do not guarantee clean turn-on/turn-off transitions or short storage time. While it may function in low-frequency (<10 kHz), non-critical switching roles, ON Semiconductor specifies no storage time (t_s) or fall time (t_f) parameters-indicating it is not characterized or warranted for switching use.

Does the 2SA1318S-AA meet RoHS and lead-free requirements?

Yes-the 2SA1318S-AA is manufactured with lead-free terminations and complies with RoHS Directive 2011/65/EU. The TO-92MOD package uses matte tin plating over copper leads, and the device carries the "Pb-Free" marking per ON Semiconductor's packaging standards. Full compliance documentation is available through Aetrix Electronics' material declarations portal.

2SA1318S-AA 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):: 200 mA

Voltage - Collector Emitter Breakdown (Max):: 50 V

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 10mA, 100mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 140 @ 1mA, 6V

Power - Max:: 500 mW

Frequency - Transition:: 200MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 3-NP

2SA1318S-AA FAQ

1.How can I place an order for 2SA1318S-AA through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SA1318S-AA 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 2SA1318S-AA reliable?

The price and inventory of 2SA1318S-AA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SA1318S-AA is usually 5 days.

3.What payment methods are accepted for 2SA1318S-AA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SA1318S-AA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SA1318S-AA?

2SA1318S-AA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SA1318S-AA 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 2SA1318S-AA?

For technical support, including 2SA1318S-AA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SA1318S-AA requirements.

6.How does Aetrix verify that 2SA1318S-AA is sourced from the original manufacturer or authorized distributors?

All 2SA1318S-AA 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 2SA1318S-AA meets industry standards.

7.What is the process for return or replacement of 2SA1318S-AA?

All 2SA1318S-AA units undergo pre-shipment inspection (PSI). If there is an issue with 2SA1318S-AA, 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 2SA1318S-AA part is unused and in its original packaging.

Return procedure for 2SA1318S-AA:

1.Submit a request within 90 days.

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

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