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

onsemi 2SB1203S-E

Name: 2SB1203S-E
Brand: onsemi
SKU: 2SB1203S-E
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SB1203S-E

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-251-3 Short Leads, IPAK, TO-251AA

Datasheet:: 2SB1203S-E.pdf

Description:: TRANS PNP 50V 5A TP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2SB1203S-E from onsemi is a PNP bipolar junction transistor designed for high-current switching in relay drivers, inverters, and DC-DC converters. It delivers V_CEO = –50 V, I_C = –5 A, V_CE(sat) = –220 mV (typ) at I_C = –3 A / I_B = –0.15 A, f_T = 180 MHz, and operates in the TP (TO-251/SC-64) package.

For engineers reviewing the 2SB1203S-E datasheet, pinout, applications, or equivalent options, this device is selected for low-saturation-voltage, fast-switching PNP roles in industrial power control, automotive load switching, and high-efficiency converter topologies where thermal performance and h_FE linearity are critical.

Technical Context

The 2SB1203S-E is a discrete PNP BJT optimized for linear and switching operation with guaranteed h_FE rank S (140–280 at I_C = –0.5 A), low V_CE(sat), and fast switching (t_on = 50 ns, t_f = 20 ns). Its structure supports high-current pulse handling (I_CP = –8 A) and stable gain across temperature (–25°C to 75°C).

It shares electrical characteristics and package footprint with the complementary NPN 2SD1203T-E, enabling matched pair use in push-pull and H-bridge configurations. The TP package provides TO-251-compatible leadframe geometry with exposed collector terminals (pins 2 & 4) for enhanced thermal dissipation up to 20 W at T_C = 25°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	–50 V - Maximum safe collector-emitter voltage under open-base conditions; defines blocking capability in high-side switch applications.
I_C	–5 A - Continuous DC collector current; supports robust load driving without forced cooling in ambient ≤25°C.
V_CE(sat)	–220 mV (typ) at I_C = –3 A / I_B = –0.15 A - Low saturation voltage minimizes conduction loss and self-heating in power switching.
f_T	180 MHz - Gain-bandwidth product enabling reliable operation up to ~10–20 MHz switching frequencies with adequate drive.
h_FE	140–280 (Rank S) at V_CE = –2 V, I_C = –0.5 A - Tight DC current gain spread ensures predictable base drive requirements in production designs.
P_C @ T_C	20 W - Collector power dissipation at case temperature 25°C; requires heatsinking for sustained >1 W operation.
t_f	20 ns - Fast fall time reduces switching transition losses and EMI in hard-switched topologies.

Pinout & Package

2SB1203S-E is housed in the TP package (JEDEC TO-251, JEITA SC-64), a 4-pin single-ended leadframe package with dual collector terminals for improved thermal and current handling. The package features an exposed metal tab (collector) and is compatible with standard TO-251 footprints.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control input; requires –0.15 A base current to saturate at –3 A collector current; low V_BE(sat) (–0.95 V typ) eases driver design.
2	Collector	Main current output terminal; electrically tied to pin 4; connected to heatsink or PCB copper for thermal management.
3	Emitter	Current return path; common reference for base drive; polarity reversed vs. NPN devices (current flows into emitter).
4	Collector	Second collector terminal; parallel-connected to pin 2 to reduce bondwire resistance and improve current sharing and thermal spreading.

Key Features

Feature	Design Value
Low V_CE(sat)	–220 mV typical at I_C = –3 A enables <1 W conduction loss per device in 5 A switching paths.
High f_T	180 MHz bandwidth supports clean square-wave switching up to 20 MHz with minimal phase lag in driver feedback loops.
h_FE linearity	Stable gain across I_C range (0.1–4 A) simplifies bias network design and improves current-source accuracy in analog circuits.
Fast switching	20 ns fall time + 50 ns turn-on time reduces total transition loss and allows higher PWM frequencies without excessive heating.
TP package thermal design	Dual-collector leads and exposed tab enable 20 W dissipation at T_C = 25°C - 2× higher than standard TO-92 equivalents.

Applications

Industrial Relay Drivers	DC-DC Converter Switches
Use Scenario: Driving 24 V/2 A electromagnetic relays in PLC I/O modules with microcontroller GPIO-level base control. IC Role / Device Role / Timing Role: High-current PNP switch sinking relay coil current to ground; operates in saturation with fixed base resistor bias. Use Value: V_CE(sat) ≤ –280 mV ensures <0.6 W relay-coil power loss and eliminates need for active base drive circuitry.	Use Scenario: Upper-side switch in non-isolated buck converter delivering 12 V/3 A from 48 V bus in telecom power supplies. IC Role / Device Role / Timing Role: Synchronous rectifier replacement in quasi-resonant topology; switched at 100 kHz with gate driver assistance. Use Value: 180 MHz f_T and 20 ns t_f maintain low switching loss (<5% of total loss) at 100 kHz with minimal snubber requirements.
Automotive Load Switching	Inverter Half-Bridge Stages
Use Scenario: Controlling 12 V solenoid valves in engine control units where load dump transients exceed 40 V. IC Role / Device Role / Timing Role: High-side switch with integrated flyback protection; handles repetitive –60 V V_CBO stress during inductive kickback. Use Value: V_(BR)CBO = –60 V and T_j = 150°C rating ensure reliability under ISO 7637-2 Pulse 5a conditions without external clamping.	Use Scenario: Complementary PNP/NPN pair (with 2SD1203T-E) in motor drive half-bridge for 24 V BLDC fans. IC Role / Device Role / Timing Role: PNP upper switch paired with NPN lower switch; driven by isolated gate driver with dead-time control. Use Value: Matched h_FE rank and identical TP packaging enable balanced current sharing and thermal coupling in compact layouts.

Industrial Relay Drivers

DC-DC Converter Switches

Use Scenario: Driving 24 V/2 A electromagnetic relays in PLC I/O modules with microcontroller GPIO-level base control.

IC Role / Device Role / Timing Role: High-current PNP switch sinking relay coil current to ground; operates in saturation with fixed base resistor bias.

Use Value: V_CE(sat) ≤ –280 mV ensures <0.6 W relay-coil power loss and eliminates need for active base drive circuitry.

Use Scenario: Upper-side switch in non-isolated buck converter delivering 12 V/3 A from 48 V bus in telecom power supplies.

IC Role / Device Role / Timing Role: Synchronous rectifier replacement in quasi-resonant topology; switched at 100 kHz with gate driver assistance.

Use Value: 180 MHz f_T and 20 ns t_f maintain low switching loss (<5% of total loss) at 100 kHz with minimal snubber requirements.

Automotive Load Switching

Inverter Half-Bridge Stages

Use Scenario: Controlling 12 V solenoid valves in engine control units where load dump transients exceed 40 V.

IC Role / Device Role / Timing Role: High-side switch with integrated flyback protection; handles repetitive –60 V V_CBO stress during inductive kickback.

Use Value: V_(BR)CBO = –60 V and T_j = 150°C rating ensure reliability under ISO 7637-2 Pulse 5a conditions without external clamping.

Use Scenario: Complementary PNP/NPN pair (with 2SD1203T-E) in motor drive half-bridge for 24 V BLDC fans.

IC Role / Device Role / Timing Role: PNP upper switch paired with NPN lower switch; driven by isolated gate driver with dead-time control.

Use Value: Matched h_FE rank and identical TP packaging enable balanced current sharing and thermal coupling in compact layouts.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP high-current switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD2955RLG	V_CEO = –60 V, I_C = –10 A, V_CE(sat) = –1.2 V (min) at I_C = –5 A - higher saturation voltage, larger TO-220 package.	Higher power dissipation tolerance but slower switching (t_f = 150 ns); suited for lower-frequency, higher-current linear regulation.	Select when absolute maximum V_CEO margin >10 V is required and layout space permits TO-220 mounting.
2SA1943	V_CEO = –230 V, I_C = –15 A, f_T = 30 MHz - much higher voltage/current rating but significantly lower bandwidth and larger TO-3P package.	Designed for audio amplifier output stages; over-specified for 50 V switching; poor f_T/power ratio for SMPS use.	Choose only for legacy audio designs requiring direct drop-in replacement; not recommended for modern switching applications.

Compared with MJD2955RLG and 2SA1943, the 2SB1203S-E offers superior switching speed and lower conduction loss in compact TP packaging - making it optimal for space-constrained, medium-frequency (≤200 kHz) industrial and automotive switching where thermal interface efficiency matters.

Availability

2SB1203S-E is available at Aetrix Electronics and suitable for industrial relay drivers, DC-DC converter switches, and automotive load switching requiring stable component supply, RoHS-compliant packaging, and consistent h_FE binning.

Supply support for 2SB1203S-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 specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and IoT applications.

The 2SB1203S-E belongs to onsemi's general-purpose bipolar transistor family engineered for high-reliability, high-current switching in harsh environments - emphasizing low V_CE(sat), fast transitions, and rugged package construction.

FAQ

What is the package type and lead count for 2SB1203S-E?

The 2SB1203S-E uses the TP package (JEDEC TO-251, JEITA SC-64), a 4-pin surface-mountable leadframe package with pins 2 and 4 both connected to the collector. This dual-collector configuration improves thermal conduction and current handling versus standard 3-pin variants.

Does 2SB1203S-E have Pb-free and halogen-free options?

Yes - the 2SB1203S-E is Pb-free only. For Pb-free and halogen-free compliance, select the 2SB1203S-H variant. Both versions share identical electrical specifications and TP package dimensions, differing only in material content certification.

What is the h_FE rank for 2SB1203S-E and how is it marked?

The 2SB1203S-E is ranked S, indicating a DC current gain (h_FE) range of 140–280 at V_CE = –2 V and I_C = –0.5 A. This rank is laser-marked on the device body as "S" alongside the part number "2SB1203" and lot code.

Can 2SB1203S-E be used in parallel with other transistors for higher current?

Yes - the 2SB1203S-E's tight h_FE binning (Rank S) and low V_CE(sat) variation support current sharing when paralleled with identical units. Use individual base resistors and symmetric PCB layout to ensure thermal and electrical balance; derate total current by 20% for reliability.

What is the maximum pulsed collector current rating for 2SB1203S-E?

The 2SB1203S-E supports I_CP = –8 A for short-duration pulses (1 ms, duty cycle ≤10%). This rating applies under specified test conditions (T_C = 25°C) and enables surge current handling in motor start-up or inductive load switching without device failure.

2SB1203S-E Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-251-3 Short Leads, IPAK, TO-251AA

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 5 A

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

Vce Saturation (Max) @ Ib, Ic:: 550mV @ 150mA, 3A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 140 @ 500mA, 2V

Power - Max:: 1 W

Frequency - Transition:: 130MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TP

2SB1203S-E FAQ

1.How can I place an order for 2SB1203S-E through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SB1203S-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 2SB1203S-E reliable?

The price and inventory of 2SB1203S-E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SB1203S-E is usually 5 days.

3.What payment methods are accepted for 2SB1203S-E?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SB1203S-E transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SB1203S-E?

2SB1203S-E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SB1203S-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 2SB1203S-E?

For technical support, including 2SB1203S-E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SB1203S-E requirements.

6.How does Aetrix verify that 2SB1203S-E is sourced from the original manufacturer or authorized distributors?

All 2SB1203S-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 2SB1203S-E meets industry standards.

7.What is the process for return or replacement of 2SB1203S-E?

All 2SB1203S-E units undergo pre-shipment inspection (PSI). If there is an issue with 2SB1203S-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 2SB1203S-E part is unused and in its original packaging.

Return procedure for 2SB1203S-E:

1.Submit a request within 90 days.

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

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