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

onsemi 2SA2127

Name: 2SA2127
Brand: onsemi
SKU: 2SA2127
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SA2127

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 Long Body

Datasheet:: 2SA2127.pdf

Description:: TRANS PNP 50V 2A 3-MP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2SA2127 from onsemi is a PNP bipolar junction transistor (BJT) rated for -50 V V_CEO, -2 A I_C, and 1 W P_C, featuring low V_CE(sat) (–0.4 V max at –1 A/–50 mA), high h_FE (200–560 at –100 mA), and 420 MHz f_T; used in relay drivers, voltage regulators, and lamp drivers where compact, robust switching is required.

For engineers reviewing the 2SA2127 datasheet, pinout, applications, or equivalent options, key selection criteria include its SC-51 (TO-92 variant) package, verified –50 V breakdown ratings, low saturation voltage under high current, wide active safe operating area (ASO), and MBIT process-derived reliability in industrial control circuits.

Technical Context

The 2SA2127 is a single PNP BJT fabricated using onsemi's MBIT (Modified Base Island Technology) process, enabling high current gain consistency and improved thermal stability. It supports DC and pulse operation up to –4 A I_CP, with validated switching performance: t_on = 35 ns, t_stg = 250 ns, t_f = 24 ns under specified test conditions (V_CC = –25 V, R_L = 50 Ω).

Its electrical behavior is characterized by tight parameter distributions across temperature: h_FE remains ≥40 at –1.5 A, V_CE(sat) stays ≤ –0.4 V at –1 A/–50 mA, and C_ob is 16 pF at –10 V V_CB, supporting stable operation in linear and switching modes from –25°C to +75°C ambient.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	–50 V - Maximum allowable collector-emitter voltage before breakdown; enables use in 48 V rail and higher industrial power control.
I_C	–2 A - Continuous collector current rating; supports medium-power load switching without forced cooling.
V_CE(sat)	–0.2 to –0.4 V - Low saturation voltage at –1 A/–50 mA; reduces conduction loss and heat generation in saturated-switch applications.
h_FE	200–560 (at –100 mA); ≥40 (at –1.5 A) - High and usable DC current gain across operating range; simplifies base drive design.
f_T	420 MHz - Gain-bandwidth product; confirms suitability for audio-frequency switching and moderate-speed digital interface buffering.
C_ob	16 pF at –10 V - Output capacitance; contributes to predictable rise/fall times and minimal Miller effect in common-emitter configurations.

Pinout & Package

2SA2127 is housed in the MP package - JEITA/JEDEC-registered as SC-51, equivalent to TO-92 (1-WATT) and TO-226AE - with standardized lead spacing and epoxy body optimized for through-hole mounting and manual rework.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current exit terminal; connected to most positive potential in PNP configuration; requires proper thermal path when dissipating >0.5 W.
2	Collector	Current entry terminal; tied to load or supply rail; electrically isolated from case in this plastic package.
3	Base	Control input; drives transistor into saturation or cutoff; requires current-limiting resistor per h_FE and I_C target.

Key Features

Feature	Design Value
MBIT process technology	Enables tighter h_FE distribution and improved thermal resistance vs. standard planar BJTs.
Low V_CE(sat)	–0.4 V max at –1 A ensures <0.4 W conduction loss, reducing heatsink requirements in relay driver stages.
Wide ASO (Active Safe Operating Area)	Validated for single-pulse I_CP = –4 A with no second breakdown; supports robust transient load handling.
High f_T and low C_ob	420 MHz f_T and 16 pF C_ob enable clean 100 kHz–1 MHz switching with minimal overshoot in inductive loads.

Applications

Voltage Regulator Control Stage	Relay Driver Circuit
Use Scenario: Linear pass transistor in adjustable negative-voltage regulators (e.g., –5 V to –24 V outputs). IC Role / Device Role / Timing Role: PNP series pass element regulating output by modulating emitter-collector current based on error amplifier feedback. Use Value: Low V_CE(sat) minimizes dropout voltage; high h_FE reduces base drive burden on op-amp error amplifier.	Use Scenario: Driving 12 V/24 V electromagnetic relays in PLC I/O modules and industrial controllers. IC Role / Device Role / Timing Role: Saturated switch turning relay coil on/off via microcontroller GPIO or logic-level signal. Use Value: Verified 250 ns storage time and 24 ns fall time ensure fast relay release; –50 V V_CEO withstands flyback spikes without snubber.
Lamp Driver for Indicator Panels	Electrical Equipment Power Switch
Use Scenario: Direct-driving incandescent or LED indicator lamps in panel-mounted instrumentation. IC Role / Device Role / Timing Role: Constant-current or switched-current source controlling lamp brightness or on/off state. Use Value: 1 W P_C rating supports continuous 200 mA lamp current at full saturation; TO-92 form factor fits dense front-panel layouts.	Use Scenario: Load switching in HVAC control boards, motor starter auxiliaries, and power sequencers. IC Role / Device Role / Timing Role: Medium-current power switch interfacing between logic controller and 24–48 V DC loads. Use Value: Wide ASO and –50 V rating allow reliable operation under inductive kick and supply transients common in equipment power rails.

Voltage Regulator Control Stage

Relay Driver Circuit

Use Scenario: Linear pass transistor in adjustable negative-voltage regulators (e.g., –5 V to –24 V outputs).

IC Role / Device Role / Timing Role: PNP series pass element regulating output by modulating emitter-collector current based on error amplifier feedback.

Use Value: Low V_CE(sat) minimizes dropout voltage; high h_FE reduces base drive burden on op-amp error amplifier.

Use Scenario: Driving 12 V/24 V electromagnetic relays in PLC I/O modules and industrial controllers.

IC Role / Device Role / Timing Role: Saturated switch turning relay coil on/off via microcontroller GPIO or logic-level signal.

Use Value: Verified 250 ns storage time and 24 ns fall time ensure fast relay release; –50 V V_CEO withstands flyback spikes without snubber.

Lamp Driver for Indicator Panels

Electrical Equipment Power Switch

Use Scenario: Direct-driving incandescent or LED indicator lamps in panel-mounted instrumentation.

IC Role / Device Role / Timing Role: Constant-current or switched-current source controlling lamp brightness or on/off state.

Use Value: 1 W P_C rating supports continuous 200 mA lamp current at full saturation; TO-92 form factor fits dense front-panel layouts.

Use Scenario: Load switching in HVAC control boards, motor starter auxiliaries, and power sequencers.

IC Role / Device Role / Timing Role: Medium-current power switch interfacing between logic controller and 24–48 V DC loads.

Use Value: Wide ASO and –50 V rating allow reliable operation under inductive kick and supply transients common in equipment power rails.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SA1015	V_CEO = –50 V, I_C = –150 mA, h_FE = 70–400 - lower current rating and gain bandwidth (f_T ≈ 80 MHz).	Not suitable for >150 mA loads; limited switching speed; acceptable only in low-power linear regulator error amplifiers.	Select 2SA1015 only if load current ≤150 mA and thermal budget permits higher V_CE(sat).
MPSA92	V_CEO = –300 V, I_C = –500 mA, V_CE(sat) = –0.5 V min - higher voltage rating but lower current and higher saturation drop.	Better for high-voltage flyback snubbing; less efficient in high-current switching due to higher V_CE(sat) and lower I_C.	Choose MPSA92 when V_CEO > –100 V is mandatory; avoid where I_C > 500 mA or efficiency is critical.

Compared with 2SA2127, 2SA1015 offers lower cost but insufficient current capacity for relay or lamp driving, while MPSA92 trades current capability for extreme voltage tolerance-neither is pin-compatible, and both require PCB layout revision for replacement.

Availability

2SA2127 is available at Aetrix Electronics and suitable for voltage regulators, relay drivers, lamp drivers, and electrical equipment requiring stable component supply, long-term industrial availability, and RoHS-compliant packaging.

Supply support for 2SA2127 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 innovation for automotive, industrial, cloud, and IoT applications.

The 2SA2127 belongs to onsemi's general-purpose bipolar transistor product line, engineered for reliability in industrial control, power management, and electromechanical interface circuits where proven ruggedness and consistent parametric performance are essential.

FAQ

What is the maximum continuous collector current rating for the 2SA2127?

The 2SA2127 has a maximum continuous collector current (I_C) rating of –2 A at T_a = 25°C. Derating applies above 25°C ambient, with total power dissipation limited to 1 W. At elevated temperatures, the safe operating current decreases per the PC–Ta curve in the datasheet, reaching ~1.2 A at 75°C ambient.

Is the 2SA2127 RoHS compliant and lead-free?

Yes, the 2SA2127 is RoHS compliant and lead-free. The ordering information explicitly states "Pb Free" for the standard 2SA2127 variant (500 pcs./bag), and the 2SA2127-AE variant is also lead-free and supplied in 1,000 pcs./box packaging with VR/RB marking compliance.

What is the pin configuration of the 2SA2127 in its MP (SC-51) package?

The 2SA2127 in the MP package uses a standard TO-92 pinout: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base - viewed with flat side facing outward and leads pointing down. This matches JEDEC TO-226AE and JEITA SC-51 mechanical specifications, confirmed by the official outline drawing and marking diagram.

Does the 2SA2127 support pulse operation beyond its DC current rating?

Yes, the 2SA2127 supports pulsed collector current (I_CP) up to –4 A under defined conditions: single pulse, <10 μs width, duty cycle ≤1%, and T_j ≤150°C. This capability is validated by the ASO curve and switching time test circuit, making it suitable for short-duration surge handling in relay and lamp inrush scenarios.

What is the typical DC current gain (h_FE) of the 2SA2127 at different operating points?

The 2SA2127 exhibits h_FE = 200–560 at V_CE = –2 V and I_C = –100 mA, and h_FE ≥40 at V_CE = –2 V and I_C = –1.5 A. These values are measured and guaranteed across temperature, confirming stable gain from small-signal to near-maximum current operation - critical for predictable base drive design in the 2SA2127.

2SA2127 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Long Body

Packaging:: Bulk

Product Status:: Active

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 2 A

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

Vce Saturation (Max) @ Ib, Ic:: 400mV @ 50mA, 1A

Current - Collector Cutoff (Max):: 1µA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 100mA, 2V

Power - Max:: 1 W

Frequency - Transition:: 420MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 3-MP

2SA2127 FAQ

1.How can I place an order for 2SA2127 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SA2127 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 2SA2127 reliable?

The price and inventory of 2SA2127 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SA2127 is usually 5 days.

3.What payment methods are accepted for 2SA2127?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SA2127 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SA2127?

2SA2127 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SA2127 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 2SA2127?

For technical support, including 2SA2127 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SA2127 requirements.

6.How does Aetrix verify that 2SA2127 is sourced from the original manufacturer or authorized distributors?

All 2SA2127 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 2SA2127 meets industry standards.

7.What is the process for return or replacement of 2SA2127?

All 2SA2127 units undergo pre-shipment inspection (PSI). If there is an issue with 2SA2127, 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 2SA2127 part is unused and in its original packaging.

Return procedure for 2SA2127:

1.Submit a request within 90 days.

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

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