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onsemi BD238STU
- Part No.:
- BD238STU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-225AA, TO-126-3
- Datasheet:
-
BD238STU.pdf
- Description:
- TRANS PNP 80V 2A TO-126-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,744
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Product details
Overview
BD238STU from Fairchild Semiconductor is a PNP epitaxial silicon transistor in TO-126 package, rated for -100 V VCBO, -80 V VCEO, -2 A DC collector current, 25 W power dissipation at TC=25°C, and 3 MHz fT, used in medium-power linear amplification and switching circuits such as voltage regulators and motor drivers.
For engineers reviewing the BD238STU datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP polarity, -80 V VCEO rating, -2 A IC capability, TO-126 thermal performance, and complementary pairing with BD237 in push-pull output stages.
Technical Context
This device operates as a medium-power PNP bipolar junction transistor optimized for linear and switching applications where robust safe operating area (SOA), low VCE(sat) of -0.6 V at IC = -1 A / IB = -0.1 A, and stable hFE ≥25 at IC = -1 A are required. It features a maximum junction temperature of 150°C and storage range from -65°C to +150°C.
The BD238STU exhibits VCEO(sus) = -80 V under IC = -100 mA / IB = 0, ICBO ≤ -100 µA at VCB = -100 V, and VBE(on) = -1.3 V at VCE = -2 V / IC = -1 A - confirming suitability for high-voltage, moderate-current biasing and saturation switching.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCBO | -100 V - maximum reverse voltage between collector and base before breakdown; enables use in high-side switch configurations up to 100 V. |
| VCEO | -80 V - maximum collector-emitter voltage under open-base condition; defines safe blocking capability in common-emitter switching. |
| IC (DC) | -2 A - continuous collector current rating; supports medium-power load control without forced cooling. |
| PC (TC=25°C) | 25 W - power dissipation limit at case temperature 25°C; requires heatsinking above ~5 W in practical operation. |
| fT | 3 MHz - current gain bandwidth product; suitable for audio-frequency amplification and PWM switching below 100 kHz. |
| VCE(sat) | -0.6 V at IC = -1 A / IB = -0.1 A - low saturation voltage reduces conduction loss in switching applications. |
| hFE | ≥25 at VCE = -2 V / IC = -1 A - sufficient DC gain for direct base drive in relay or solenoid drivers. |
Pinout & Package
BD238STU is housed in a TO-126 plastic package with integral heat slug, designed for through-hole mounting and conductive thermal transfer to a heatsink via the collector-connected tab.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Emitter terminal | Current exit path for PNP device; connected to higher potential rail in typical high-side switch configuration. |
| 2 (Collector) | Collector terminal | Current entry point; electrically tied to metal tab for thermal and electrical connection to heatsink. |
| 3 (Base) | Control input | Current-controlled gate; requires negative base current relative to emitter to turn on the transistor. |
Key Features
| Feature | Design Value |
|---|---|
| Complementary pairing | Explicitly designed as PNP complement to BD237 NPN transistor for push-pull amplifier and H-bridge output stages. |
| High VCEO(sus) | -80 V sustaining voltage ensures reliable operation under inductive load switching with flyback transients. |
| Low VCE(sat) | -0.6 V saturation voltage minimizes power loss and self-heating during high-current conduction. |
| Robust SOA | Defined Safe Operating Area curve supports pulsed operation up to -6 A with 100 µs pulse width and 1.5% duty cycle. |
| Thermal stability | 150°C max junction temperature and derated power curve allow operation in industrial ambient environments up to 80°C case temperature. |
Applications
| Linear Voltage Regulator | DC Motor Driver |
|---|---|
Use Scenario: Used as pass transistor in adjustable series regulators delivering up to 1.5 A output with <1% line/load regulation. IC Role / Device Role / Timing Role: PNP pass element controlling output voltage by modulating emitter-collector current based on error amplifier feedback. Use Value: -80 V VCEO and -2 A IC enable regulation from 48 V input rails; low VCE(sat) maintains efficiency above 92% at full load. | Use Scenario: Drives 24 V brushed DC motors in industrial actuators requiring bidirectional control via H-bridge topology. IC Role / Device Role / Timing Role: High-side PNP switch in one leg of complementary H-bridge, paired with BD237 on low-side. Use Value: Complementary pinout and matching SOA with BD237 simplify layout; -100 µA ICBO ensures minimal leakage-induced drift in idle state. |
| Audio Power Amplifier | Relay/Solenoid Driver |
Use Scenario: Output stage in Class AB audio amplifiers delivering 5–10 W into 8 Ω loads with THD <0.5% at 1 kHz. IC Role / Device Role / Timing Role: PNP output transistor in push-pull pair, handling negative half-cycle current delivery. Use Value: 3 MHz fT and hFE ≥25 support stable gain up to 20 kHz; SOA allows safe clipping without secondary breakdown. | Use Scenario: Direct-drive interface for 12 V/24 V electromagnetic relays and solenoids in PLC I/O modules. IC Role / Device Role / Timing Role: Switching transistor providing controlled current sink to relay coil with fast turn-off via base discharge. Use Value: -1.3 V VBE(on) ensures reliable turn-on with standard logic-level base drive; TO-126 tab enables mechanical mounting to chassis ground. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP medium-power switching and linear applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJD213G | TO-220 package, -100 V VCBO, -80 V VCEO, -2 A IC, but hFE min = 30 vs. BD238STU's 25; higher thermal resistance due to larger package footprint. | Same voltage/current ratings but lacks explicit complementary pairing documentation with NPN counterparts like MJD214. | Preferred when higher hFE margin or TO-220 mounting compatibility is needed; requires PCB layout change. |
| BD238D | Same die and specs as BD238STU but in TO-126 variant without suffix 'TU'; identical electricals and pinout per Fairchild Rev. A datasheet. | No functional difference; 'D' and 'STU' denote same device with minor packaging or tape-and-reel coding variation. | Select BD238D only if legacy BOM specifies that part number; BD238STU is functionally identical and fully interchangeable. |
Compared with MJD213G and BD238D, the BD238STU offers documented complementary pairing with BD237, TO-126 thermal interface optimization, and verified SOA for pulsed inductive loads - making it preferred for space-constrained, thermally sensitive, or matched-pair designs.
Availability
BD238STU is available at Aetrix Electronics and suitable for linear voltage regulators, DC motor drivers, audio power amplifiers, and relay/solenoid drivers requiring stable component supply across industrial control, instrumentation, and embedded power systems.
Supply support for BD238STU 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog, discrete, and power management ICs before its acquisition by ON Semiconductor in 2016.
The BD238STU belongs to Fairchild's legacy medium-power PNP transistor family, engineered for robust linear amplification and switching in industrial and automotive-qualified power stages.
FAQ
What is the pin configuration of BD238STU?
The BD238STU uses a TO-126 package with three terminals: Pin 1 is Emitter, Pin 2 is Collector (connected to the metal tab), and Pin 3 is Base. This configuration is standardized across the BD234/236/238 series and matches complementary NPN devices like BD237 for consistent PCB layout in push-pull designs. The BD238STU pinout supports direct heatsink mounting via the collector tab.
Is BD238STU compatible with BD237 in push-pull circuits?
Yes, BD238STU is explicitly specified as the PNP complement to BD237 NPN transistor. Their matched VCEO, IC, SOA, and TO-126 pinout enable symmetrical push-pull operation in audio amplifiers and H-bridge drivers. The BD238STU datasheet confirms this pairing in its Applications section, ensuring balanced conduction and thermal behavior when used with BD237.
What is the maximum safe operating voltage for BD238STU?
The BD238STU has a maximum collector-base voltage (VCBO) of -100 V and a collector-emitter sustaining voltage (VCEO(sus)) of -80 V at IC = -100 mA. For reliable long-term operation, design should limit VCEO to ≤ -80 V under all conditions, including inductive kickback. Exceeding -80 V risks secondary breakdown, especially without snubbing - a key constraint defined in the BD238STU absolute maximum ratings table.
Does BD238STU require a heatsink in normal operation?
Yes, BD238STU requires a heatsink when dissipating more than ~5 W continuously. Its 25 W PC rating applies only at TC = 25°C; derating begins immediately above that temperature per the published power derating curve. At 80°C case temperature, usable power drops to ~12 W. The TO-126 metal tab must be thermally coupled to the heatsink - an essential requirement for BD238STU in regulator or motor driver applications.
What is the DC current gain (hFE) range for BD238STU?
The BD238STU has a minimum hFE of 25 at VCE = -2 V and IC = -1 A, and a minimum of 40 at VCE = -2 V and IC = -150 mA. Typical hFE is higher but not guaranteed. This gain profile supports direct TTL or microcontroller GPIO base drive at low currents, while ensuring predictable saturation at full load - a verified characteristic confirmed in the BD238STU electrical characteristics table.
BD238STU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-225AA, TO-126-3
- Packaging:
- Tube
- Product Status:
- Obsolete
- Transistor Type:
- PNP
- Current - Collector (Ic) (Max):
- 2 A
- Voltage - Collector Emitter Breakdown (Max):
- 80 V
- Vce Saturation (Max) @ Ib, Ic:
- 600mV @ 100mA, 1A
- Current - Collector Cutoff (Max):
- 100µA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 25 @ 1A, 2V
- Power - Max:
- 25 W
- Frequency - Transition:
- 3MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-126-3
BD238STU FAQ
1.How can I place an order for BD238STU through Aetrix?
Please submit a Request for Quotation (RFQ) for BD238STU 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 BD238STU reliable?
The price and inventory of BD238STU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD238STU is usually 5 days.
3.What payment methods are accepted for BD238STU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD238STU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BD238STU?
BD238STU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BD238STU 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 BD238STU?
For technical support, including BD238STU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD238STU requirements.
6.How does Aetrix verify that BD238STU is sourced from the original manufacturer or authorized distributors?
All BD238STU 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 BD238STU meets industry standards.
7.What is the process for return or replacement of BD238STU?
All BD238STU units undergo pre-shipment inspection (PSI). If there is an issue with BD238STU, 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 BD238STU part is unused and in its original packaging.
Return procedure for BD238STU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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