Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

onsemi 2SA2124-TD-E

Name: 2SA2124-TD-E
Brand: onsemi
SKU: 2SA2124-TD-E
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: 2SA2124-TD-E

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-243AA

Datasheet:: 2SA2124-TD-E.pdf

Description:: TRANS PNP 30V 2A PCP

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:614

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

2SA2124-TD-E from onsemi is a PNP bipolar junction transistor (BJT) designed for medium-power switching and linear amplification in discrete power control circuits. It features -30 V V_CEO, -2 A continuous I_C, low -0.4 V typical V_CE(sat) at -1.5 A, 440 MHz f_T, and operates up to 150 °C junction temperature - used in relay drivers, lamp drivers, and voltage regulators.

For engineers reviewing the 2SA2124-TD-E datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP polarity, SC-62 (SOT-89) package thermal performance, saturation voltage under high-current drive, h_FE consistency across -100 mA to -1.5 A, and switching timing (t_on/t_f) in pulse-width-controlled loads.

Technical Context

This device implements a silicon PNP structure fabricated using onsemi's MBIT process, enabling low V_CE(sat) and high-speed switching with t_on = 45 ns and t_f = 23 ns. Its gain-bandwidth product of 440 MHz supports stable operation in audio-frequency amplifiers and fast-switching DC-DC feedback paths.

The 2SA2124-TD-E is rated for -30 V V_CBO/V_CEO, -6 V V_EBO, and delivers h_FE = 200–560 at -100 mA and h_FE = 65 at -1.5 A - indicating robust current gain retention under load. Thermal dissipation is specified at 3.5 W at T_c = 25 °C when mounted on ceramic substrate.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-30 V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration
I_C (continuous)	-2 A - Continuous collector current rating defining steady-state power switching capability
V_CE(sat)	-0.4 V max at I_C = -1.5 A, I_B = -75 mA - Low saturation voltage minimizes conduction loss in saturated-switch applications
f_T	440 MHz - Gain-bandwidth product confirming suitability for audio amplification and high-speed switching
h_FE	65 min at I_C = -1.5 A - Verified DC current gain under high-current bias, critical for driver stage reliability
P_C (T_c=25°C)	3.5 W - Maximum power dissipation with case temperature held at 25 °C, requiring heatsinking in high-duty-cycle use
t_f	23 ns - Fall time defining minimum off-state transition duration in PWM-driven loads

Pinout & Package

2SA2124-TD-E is housed in a PCP package - JEITA/JEDEC-registered as SC-62, identical to SOT-89 and TO-243 - featuring surface-mount footprint, exposed collector tab for thermal conduction, and 1,000 pcs./reel tape-and-reel packaging (TD variant).

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal for forward-biased PNP operation; requires negative base current relative to emitter to turn on
2	Collector	Main current sink terminal; electrically connected to exposed metal tab for thermal and electrical grounding in PCB layout
3	Emitter	Reference terminal and current source node; typically tied to higher potential (e.g., V_CC) in PNP switch configurations

Key Features

Feature	Design Value
Low V_CE(sat)	-0.4 V max ensures <0.6 W conduction loss at -1.5 A, reducing thermal stress in relay/lamp drivers
High-speed switching	45 ns t_on/23 ns t_f enables clean transitions in 10–100 kHz PWM control without shoot-through risk
Large current capacity	-2 A continuous / -5 A pulsed rating supports direct driving of solenoids, LEDs, and small motors without external buffers
MBIT process technology	Enables tight parameter distribution and improved h_FE stability across temperature (-25°C to +75°C curves confirmed)

Applications

Voltage Regulator Pass Element	Relay Driver Stage
Use Scenario: Used as series pass transistor in linear voltage regulators delivering up to 2 A output current. IC Role / Device Role / Timing Role: PNP current amplifier controlling output voltage via base bias from error amplifier. Use Value: Low V_CE(sat) reduces dropout voltage and improves efficiency at full load; h_FE ≥65 ensures stable loop gain under varying line/load conditions.	Use Scenario: Drives electromagnetic relays with coil currents up to 1.5 A in industrial control panels. IC Role / Device Role / Timing Role: High-current saturated switch turning relay coil on/off with minimal delay. Use Value: Fast t_f = 23 ns prevents contact bounce during de-energization; -30 V V_CEO accommodates inductive kickback suppression.
Lamp Driver for Incandescent/LED Arrays	Electrical Equipment Power Switch
Use Scenario: Controls 12 V automotive lamps or multi-LED strings in dashboard lighting modules. IC Role / Device Role / Timing Role: Medium-power load switch interfacing microcontroller GPIOs to high-current loads. Use Value: -2 A I_C rating handles peak inrush of cold filaments; exposed collector tab aids thermal management in compact enclosures.	Use Scenario: Implements main power enable/disable in programmable logic controllers (PLCs) and test equipment. IC Role / Device Role / Timing Role: Discrete power path controller managing 24 V system rail activation. Use Value: Robust -30 V V_CBO and 150 °C T_j rating ensure reliability in industrial ambient temperatures and transient overvoltage events.

Voltage Regulator Pass Element

Relay Driver Stage

Use Scenario: Used as series pass transistor in linear voltage regulators delivering up to 2 A output current.

IC Role / Device Role / Timing Role: PNP current amplifier controlling output voltage via base bias from error amplifier.

Use Value: Low V_CE(sat) reduces dropout voltage and improves efficiency at full load; h_FE ≥65 ensures stable loop gain under varying line/load conditions.

Use Scenario: Drives electromagnetic relays with coil currents up to 1.5 A in industrial control panels.

IC Role / Device Role / Timing Role: High-current saturated switch turning relay coil on/off with minimal delay.

Use Value: Fast t_f = 23 ns prevents contact bounce during de-energization; -30 V V_CEO accommodates inductive kickback suppression.

Lamp Driver for Incandescent/LED Arrays

Electrical Equipment Power Switch

Use Scenario: Controls 12 V automotive lamps or multi-LED strings in dashboard lighting modules.

IC Role / Device Role / Timing Role: Medium-power load switch interfacing microcontroller GPIOs to high-current loads.

Use Value: -2 A I_C rating handles peak inrush of cold filaments; exposed collector tab aids thermal management in compact enclosures.

Use Scenario: Implements main power enable/disable in programmable logic controllers (PLCs) and test equipment.

IC Role / Device Role / Timing Role: Discrete power path controller managing 24 V system rail activation.

Use Value: Robust -30 V V_CBO and 150 °C T_j rating ensure reliability in industrial ambient temperatures and transient overvoltage events.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SA1774E	V_CEO = -20 V, I_C = -1 A, f_T = 200 MHz - lower voltage/current ratings and bandwidth	Suitable only for sub-1 A, low-voltage (<15 V) switching; not recommended for 24 V relay coils or 2 A regulators	Select only if design operates below 15 V and requires smaller footprint or lower cost; verify h_FE drop at target I_C.
MJD2955T4G	V_CEO = -60 V, I_C = -10 A, TO-220 package - higher voltage/current but larger thermal mass and slower t_f (100 ns)	Preferred for high-reliability 48 V systems or >5 A loads; requires heatsink and board area not needed for 2SA2124-TD-E	Choose when extended voltage margin or higher surge tolerance is required; avoid if space-constrained or high-frequency switching is critical.

Compared with 2SA2124-TD-E, 2SA1774E trades off voltage/current headroom for compactness, while MJD2955T4G provides greater ruggedness at the expense of speed and PCB area - making 2SA2124-TD-E optimal for balanced 24 V, ~2 A, surface-mount switching where thermal and timing constraints are moderate.

Availability

2SA2124-TD-E is available at Aetrix Electronics and suitable for voltage regulators, relay drivers, and lamp drivers requiring stable component supply in industrial control, automotive body electronics, and embedded power management systems.

Supply support for 2SA2124-TD-E 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, delivering silicon solutions for automotive, industrial, cloud, and IoT applications.

The 2SA2124-TD-E belongs to onsemi's general-purpose bipolar transistor product line, engineered for reliable discrete power switching and amplification in cost-sensitive, thermally constrained applications.

FAQ

Is 2SA2124-TD-E still in active production?

No - the official onsemi documentation explicitly states "DISCONTINUED" and "NOT RECOMMENDED FOR NEW DESIGN." While limited legacy stock may be available through authorized channels including Aetrix Electronics, new designs should select qualified alternatives such as MJD2955T4G or consult onsemi for updated PNP transistor recommendations. The 2SA2124-TD-E remains supported for existing production continuity.

What does the 'TD' in 2SA2124-TD-E signify?

The 'TD' suffix denotes the tape-and-reel packing type per onsemi's ordering nomenclature - specifically, 1,000 pieces per reel with Pb-free (RoHS-compliant) finish. It does not indicate a functional variant; all electrical and thermal specifications for 2SA2124-TD-E match the base 2SA2124 device in PCP package.

Can 2SA2124-TD-E replace 2SA1015 or 2SA1213 in existing circuits?

Direct replacement is not assured: 2SA1015 has V_CEO = -50 V and h_FE = 70–240, while 2SA1213 offers V_CEO = -120 V and I_C = -1 A. The 2SA2124-TD-E's -30 V rating and -2 A current make it unsuitable for higher-voltage rails, and its h_FE profile differs significantly at low I_C. Circuit validation is required before substitution.

What is the thermal resistance of 2SA2124-TD-E in its PCP package?

onsemi specifies maximum power dissipation of 3.5 W at T_c = 25 °C and 1.3 W at T_a = 25 °C (mounted on 450 mm² × 0.8 mm ceramic substrate). While exact R_θJC is not published, the exposed collector tab in the PCP package enables effective thermal coupling to copper pour or heatsink - typical R_θJA is estimated at ~192 °C/W under standard JEDEC test conditions.

Does 2SA2124-TD-E support high-frequency switching above 100 kHz?

Yes - with f_T = 440 MHz and measured t_on/t_f of 45 ns/23 ns, the 2SA2124-TD-E supports clean switching up to ~1–2 MHz in optimized layouts. However, practical use above 100 kHz requires attention to base drive strength (to minimize storage time), PCB parasitics, and load inductance - especially given its -1.5 A I_C saturation limit.

2SA2124-TD-E Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-243AA

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

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

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 400mV @ 75mA, 1.5A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 100mA, 5V

Power - Max:: 3.5 W

Frequency - Transition:: 440MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: PCP

2SA2124-TD-E FAQ

1.How can I place an order for 2SA2124-TD-E through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SA2124-TD-E 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 2SA2124-TD-E reliable?

The price and inventory of 2SA2124-TD-E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SA2124-TD-E is usually 5 days.

3.What payment methods are accepted for 2SA2124-TD-E?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SA2124-TD-E transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SA2124-TD-E?

2SA2124-TD-E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SA2124-TD-E 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 2SA2124-TD-E?

For technical support, including 2SA2124-TD-E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SA2124-TD-E requirements.

6.How does Aetrix verify that 2SA2124-TD-E is sourced from the original manufacturer or authorized distributors?

All 2SA2124-TD-E 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 2SA2124-TD-E meets industry standards.

7.What is the process for return or replacement of 2SA2124-TD-E?

All 2SA2124-TD-E units undergo pre-shipment inspection (PSI). If there is an issue with 2SA2124-TD-E, 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 2SA2124-TD-E part is unused and in its original packaging.

Return procedure for 2SA2124-TD-E:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…