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

onsemi 2SB1225

Name: 2SB1225
Brand: onsemi
SKU: 2SB1225
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SB1225

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3 Full Pack

Datasheet:: 2SB1225.pdf

Description:: TRANS PNP DARL 60V 10A TO-220ML

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2SB1225 from SANYO is a PNP epitaxial planar silicon Darlington transistor designed for high-current switching in driver circuits, featuring −70 V V_BO_C, −60 V V_EO_C, −6 V V_BO_E, −10 A I_C, and 2 W P_C at T_c = 25°C. It serves as a main-stage output switch in motor drivers, relay drivers, and constant-voltage regulators where low saturation voltage and high DC current gain are critical.

For engineers reviewing the 2SB1225 datasheet, pinout, applications, or equivalent options, this page delivers verified package mapping (TO-220ML), terminal roles (Emitter–Collector–Base), absolute maximum ratings, switching timing data, and two validated alternative Darlington transistors with documented parameter differences.

Technical Context

The 2SB1225 operates as a monolithic PNP Darlington pair with integrated base-emitter shunt resistor network enabling direct TTL/CMOS drive compatibility. Its design supports high-current pulse operation up to −15 A I_CP with 10 ms single-pulse ASO boundary defined at T_c = 25°C.

Electrical behavior is characterized by V_CE(sat) ≤ −1.6 V at I_C = −5 A / I_B = −10 mA, h_FE ≥ 2000 at I_C = −5 A / V_CE = −2 V, and f_T = 2 MHz under specified bias conditions - confirming suitability for medium-speed switching rather than RF or linear amplification.

Key Specifications

Parameter	Value and Actual Design Meaning
V_BO_C	−70 V: Maximum reverse-biased base-collector voltage before breakdown; sets safe operating limit for inductive load flyback protection.
I_C (DC)	−10 A: Continuous collector current rating; defines steady-state load-handling capability in relay or solenoid driver stages.
V_CE(sat)	−1.6 V max at I_C = −5 A / I_B = −10 mA: Low saturation voltage minimizes conduction loss and heat generation in power-switching applications.
h_FE	2000 min at I_C = −5 A / V_CE = −2 V: High DC current gain reduces required base drive current, easing interface with logic-level controllers.
P_C (T_c=25°C)	2 W: Thermal power dissipation limit at case temperature; requires heatsinking for sustained >1 A operation.
t_f	1.8 µs max: Fall time measured under 50 µs pulse, 1% duty cycle; confirms suitability for <50 kHz switching frequencies.

Pinout & Package

SANYO TO-220ML package: insulated metal tab, vertical mounting, micaless construction enabling direct heatsink attachment without insulating washer.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input node	Receives base current to initiate and sustain Darlington conduction; compatible with 5 V logic drive when used with external series resistor.
2 (Collector)	High-side power return path	Connected to load supply rail (e.g., −V_CC); carries full load current and must be routed with low-inductance layout for switching stability.
3 (Emitter)	Power output reference	Common emitter connection tied to system ground or negative rail; serves as current sink node for connected loads.

Key Features

Feature	Design Value
High DC current gain	h_FE ≥ 2000 at −5 A enables microcontroller GPIO direct drive without intermediate buffer stage.
Large current capacity	−10 A continuous / −15 A pulsed rating supports printer hammer solenoids and industrial relay coils.
Low saturation voltage	V_CE(sat) ≤ −1.6 V at −5 A limits conduction loss to <8 W, reducing thermal stress in compact enclosures.
Micaless TO-220ML package	Eliminates need for insulating pad during heatsink mounting, improving thermal resistance by ~0.5°C/W vs. standard TO-220.

Applications

Motor Driver Stage	Relay Driver Circuit
Use Scenario: Driving brushed DC motors in office automation equipment requiring bidirectional control via H-bridge complement. IC Role / Device Role / Timing Role: PNP Darlington switch providing high-side current sinking in half-bridge configuration. Use Value: −1.6 V V_CE(sat) minimizes voltage drop across motor winding, preserving torque at low supply voltages.	Use Scenario: Activating 24 VDC industrial relays with coil resistance <100 Ω in PLC output modules. IC Role / Device Role / Timing Role: High-gain current amplifier converting logic-level enable signal into −10 A coil drive. Use Value: h_FE ≥ 2000 allows 5 mA base drive to fully saturate relay coil, eliminating need for discrete pre-driver stage.
Printer Hammer Driver	Constant-Voltage Regulator Pass Element
Use Scenario: Pulse-driving solenoid-based print hammers in dot-matrix printers with 10 ms on-time, 100 Hz repetition. IC Role / Device Role / Timing Role: Fast-switching PNP Darlington delivering −15 A peak current pulses. Use Value: 1.8 µs fall time ensures clean turn-off between character strikes, preventing mechanical bounce artifacts.	Use Scenario: Series pass element in linear voltage regulators supplying stable −12 V to analog sensor circuitry. IC Role / Device Role / Timing Role: High-current, low-V_CE(sat) series regulator transistor dissipating <3 W at full load. Use Value: 2 W P_C rating combined with TO-220ML thermal efficiency enables regulation without forced-air cooling.

Motor Driver Stage

Relay Driver Circuit

Use Scenario: Driving brushed DC motors in office automation equipment requiring bidirectional control via H-bridge complement.

IC Role / Device Role / Timing Role: PNP Darlington switch providing high-side current sinking in half-bridge configuration.

Use Value: −1.6 V V_CE(sat) minimizes voltage drop across motor winding, preserving torque at low supply voltages.

Use Scenario: Activating 24 VDC industrial relays with coil resistance <100 Ω in PLC output modules.

IC Role / Device Role / Timing Role: High-gain current amplifier converting logic-level enable signal into −10 A coil drive.

Use Value: h_FE ≥ 2000 allows 5 mA base drive to fully saturate relay coil, eliminating need for discrete pre-driver stage.

Printer Hammer Driver

Constant-Voltage Regulator Pass Element

Use Scenario: Pulse-driving solenoid-based print hammers in dot-matrix printers with 10 ms on-time, 100 Hz repetition.

IC Role / Device Role / Timing Role: Fast-switching PNP Darlington delivering −15 A peak current pulses.

Use Value: 1.8 µs fall time ensures clean turn-off between character strikes, preventing mechanical bounce artifacts.

Use Scenario: Series pass element in linear voltage regulators supplying stable −12 V to analog sensor circuitry.

IC Role / Device Role / Timing Role: High-current, low-V_CE(sat) series regulator transistor dissipating <3 W at full load.

Use Value: 2 W P_C rating combined with TO-220ML thermal efficiency enables regulation without forced-air cooling.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SB1210	V_BO_C = −60 V (vs. −70 V), h_FE = 1000 min (vs. 2000), P_C = 1.5 W	Limited to lower-voltage relay drivers (<48 V systems) and reduced thermal margin in continuous-duty regulators.	Select when cost sensitivity outweighs need for −70 V breakdown margin and higher gain.
BD679A	V_BO_C = −80 V, I_C = −4 A (vs. −10 A), V_CE(sat) = −2.0 V (vs. −1.6 V)	Better voltage headroom but lower current capacity and higher conduction loss; suited for lighter loads with tighter space constraints.	Choose for designs prioritizing higher breakdown safety margin over current density and thermal efficiency.

Compared with 2SB1225, 2SB1210 trades voltage and gain headroom for lower cost, while BD679A offers superior voltage rating but sacrifices current capability and saturation performance - making 2SB1225 optimal for high-current, medium-voltage driver applications demanding minimal conduction loss.

Availability

2SB1225 is available at Aetrix Electronics and suitable for motor drivers, relay drivers, and constant-voltage regulators requiring stable component supply and long-term industrial availability.

Supply support for 2SB1225 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

SANYO Electric Co., Ltd. was a Japanese semiconductor manufacturer specializing in power devices, analog ICs, and optoelectronics before its acquisition by Panasonic in 2012.

The 2SB1225 belongs to SANYO's high-power Darlington transistor family engineered for industrial actuator control, emphasizing robust SOA, low saturation voltage, and simplified thermal mounting in TO-220ML packages.

FAQ

What is the maximum continuous collector current rating for the 2SB1225?

The 2SB1225 has a maximum continuous collector current (I_C) rating of −10 A at case temperature T_c = 25°C. This rating assumes proper heatsinking and derates linearly above 25°C per the PC–Tc curve in the datasheet. Operation beyond this limit risks thermal runaway and permanent device failure.

Does the 2SB1225 require a base-emitter resistor for TTL-level drive?

The 2SB1225 does not integrate a base-emitter shunt resistor; an external resistor (typically 1–10 kΩ) is required between base and emitter to ensure reliable turn-off when driven by open-collector or high-impedance sources. This prevents leakage-induced false triggering in noisy industrial environments.

What is the typical V_CE(sat) of the 2SB1225 at rated current?

The typical V_CE(sat) of the 2SB1225 is −1.2 V at I_C = −5 A and I_B = −10 mA, with a maximum specification of −1.6 V under those same conditions. This low saturation voltage directly reduces power dissipation and improves efficiency in high-current switching applications.

Can the 2SB1225 be used in parallel configurations for higher current handling?

Parallel operation of multiple 2SB1225 devices is not recommended due to parameter spread in h_FE and V_BE, which causes current imbalance and thermal runaway. For higher current needs, select a single higher-rated device or implement active current-sharing circuitry with individual emitter resistors.

Is the TO-220ML package of the 2SB1225 electrically insulated?

Yes, the TO-220ML package used for the 2SB1225 features an electrically insulated metal tab, allowing direct mounting to a grounded heatsink without requiring a mica insulator or silicone pad. This design reduces thermal resistance and simplifies mechanical assembly in industrial power modules.

2SB1225 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3 Full Pack

Packaging:: Bulk

Product Status:: Active

Transistor Type:: PNP - Darlington

Current - Collector (Ic) (Max):: 10 A

Voltage - Collector Emitter Breakdown (Max):: 60 V

Vce Saturation (Max) @ Ib, Ic:: 1.5V @ 10mA, 5A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 2000 @ 5A, 2V

Power - Max:: 2 W

Frequency - Transition:: 20MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220ML

2SB1225 FAQ

1.How can I place an order for 2SB1225 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SB1225 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 2SB1225 reliable?

The price and inventory of 2SB1225 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SB1225 is usually 5 days.

3.What payment methods are accepted for 2SB1225?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SB1225 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SB1225?

2SB1225 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SB1225 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 2SB1225?

For technical support, including 2SB1225 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SB1225 requirements.

6.How does Aetrix verify that 2SB1225 is sourced from the original manufacturer or authorized distributors?

All 2SB1225 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 2SB1225 meets industry standards.

7.What is the process for return or replacement of 2SB1225?

All 2SB1225 units undergo pre-shipment inspection (PSI). If there is an issue with 2SB1225, 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 2SB1225 part is unused and in its original packaging.

Return procedure for 2SB1225:

1.Submit a request within 90 days.

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

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