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onsemi BD37925STU
- Part No.:
- BD37925STU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-225AA, TO-126-3
- Datasheet:
-
BD37925STU.pdf
- Description:
- TRANS NPN 80V 2A TO-126-3
- Quantity:
- Payment:
- Shipping:
Inventory:5,035
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Product details
Overview
BD37925STU from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for medium-power linear amplification and switching applications, with VCEO = 80 V, IC = 2 A (DC), PC = 25 W at TC = 25°C, hFE = 150–375 at IC = 1 A, and TO-126 package. It serves as a complement to BD380 in audio output stages and power control circuits.
For engineers reviewing the BD37925STU datasheet, pinout, applications, or equivalent options, key selection criteria include collector-emitter sustaining voltage (VCEO(sus) = 80 V), saturation voltage (VCE(sat) = 1 V @ IC = 1 A, IB = 0.1 A), DC current gain classification, safe operating area limits, and thermal derating behavior.
Technical Context
This device operates as a general-purpose bipolar junction transistor optimized for robustness in medium-power analog and switching roles. Its design supports linear operation up to 2 A DC with low VCE(sat) and stable hFE across IC = 0.15 A to 1 A, enabling use in Class AB audio drivers and relay/inductive load switches.
The BD37925STU features a rugged SOA profile validated to 80 V / 2 A continuous, with pulse-rated ICP = 3 A and tOFF = 500 ns, making it suitable for moderate-speed switching where thermal management via heatsink-mountable TO-126 package is feasible.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 80 V - Maximum continuous collector-emitter voltage before breakdown; defines upper rail limit in amplifier or switch designs. |
| IC (DC) | 2 A - Continuous collector current rating; sets maximum steady-state load drive capability. |
| PC @ TC=25°C | 25 W - Power dissipation limit at case temperature 25°C; requires heatsinking for sustained operation above ~10 W. |
| hFE (IC = 1 A) | 150–375 - DC current gain range at rated current; enables predictable base drive sizing for switching or bias stability in linear mode. |
| VCE(sat) | 1 V @ IC = 1 A, IB = 0.1 A - Low saturation voltage reduces conduction loss and self-heating in switching applications. |
| tOFF | 500 ns - Turn-off time under defined test conditions; supports operation up to ~200 kHz in non-resonant switching. |
Pinout & Package
BD37925STU is housed in a TO-126 plastic package with integral metal tab for heatsink mounting. Pin 1 is Emitter, Pin 2 is Collector (connected to tab), Pin 3 is Base - standard configuration for medium-power BJT devices requiring mechanical and thermal reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Current exit path from transistor | Connected to ground or low-side return; must handle full load current with minimal trace resistance. |
| 2 (Collector) | Current entry path into transistor | Electrically and thermally tied to metal tab; requires insulated mounting when referenced to non-ground potentials. |
| 3 (Base) | Control terminal for minority carrier injection | Drives transistor into active/saturation; requires current-limited source (IB ≤ 1 A max) per datasheet absolute rating. |
Key Features
| Feature | Design Value |
|---|---|
| High VCEO rating | 80 V enables use in 48 V industrial supplies and 60 V peak audio rails without derating. |
| Wide hFE classification | 150–375 range allows consistent gain matching across production lots for bias-critical linear stages. |
| Low VCE(sat) | 1 V at 1 A/0.1 A ensures <1 W conduction loss, reducing heatsink requirements in switching regulators. |
| Rugged SOA | Validated safe operating area up to 80 V × 2 A supports transient overloads in motor and solenoid drive. |
Applications
| Audio Power Amplifier Output Stage | DC Motor Driver (Medium Power) |
|---|---|
Use Scenario: Final push-pull stage in 10–20 W Class AB audio amplifier driving 4–8 Ω speakers. IC Role / Device Role / Timing Role: NPN output transistor delivering high-current, low-distortion signal swing with thermal stability. Use Value: VCEO = 80 V accommodates ±35 V rails; hFE ≥ 150 ensures stable bias current with minimal thermal drift. | Use Scenario: H-bridge half-bridge leg controlling 12–24 V brushed DC motors up to 1.5 A average current. IC Role / Device Role / Timing Role: Switching element turning motor winding on/off with controlled rise/fall times. Use Value: tOFF = 500 ns and VCE(sat) = 1 V minimize switching losses and heat generation during PWM operation. |
| Relay/Solenoid Driver | Linear Voltage Regulator Pass Element |
Use Scenario: Driving 24 V/500 mA industrial relays or 12 V solenoids with flyback protection. IC Role / Device Role / Timing Role: High-current saturated switch interfacing microcontroller GPIO to inductive loads. Use Value: IC = 2 A and ICP = 3 A support surge currents during coil energization without secondary breakdown. | Use Scenario: Series pass transistor in adjustable 3–30 V, 1.5 A linear regulator with external error amplifier. IC Role / Device Role / Timing Role: Current-controlled variable resistor dissipating excess input-output differential voltage. Use Value: PC = 25 W and TJ = 150°C allow regulated output under 20 V dropout at full load with proper heatsinking. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN medium-power transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJD32C | VCEO = 100 V, hFE = 20–120 (lower gain spread), TO-220 package | Better voltage margin but less linear gain consistency; larger footprint | Preferred where higher voltage headroom is critical and gain tolerance is acceptable |
| BD380 | PNP complement; identical VCEO/VCEO(sus)/IC ratings, mirrored polarity | Required only in push-pull or complementary symmetry circuits | Select BD380 only when building matched NPN-PNP pairs for balanced output stages |
Compared with BD37925STU, MJD32C offers higher voltage rating but narrower hFE range and different thermal interface, while BD380 is not a functional substitute but a polarity-matched companion-neither is pin-compatible, and both require layout adaptation.
Availability
BD37925STU is available at Aetrix Electronics and suitable for audio amplifier output stages, DC motor control, relay/solenoid drivers, and linear regulator pass elements requiring stable component supply and long-term industrial availability.
Supply support for BD37925STU 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 manufacturer specializing in power discrete devices, analog ICs, and interface solutions before its acquisition by ON Semiconductor in 2016.
The BD37925STU belongs to Fairchild's BD37x series of medium-power linear and switching transistors, engineered for reliability in industrial and consumer audio, power control, and electromechanical interface applications.
FAQ
What is the maximum continuous collector current for BD37925STU?
The BD37925STU has a maximum continuous collector current (IC) of 2 A at TC = 25°C. Derating is required above this case temperature per the power derating curve in the datasheet, with zero dissipation at TC = 150°C. This rating assumes adequate heatsinking and applies to DC or low-duty-cycle pulsed operation.
Is BD37925STU pin-compatible with BD375 or BD377?
No, BD37925STU is not pin-compatible with BD375 or BD377 in terms of electrical ratings, though all share the same TO-126 package and pinout (E-C-B). The BD37925STU is the highest-voltage variant (VCEO = 80 V), while BD375 and BD377 have lower breakdown ratings (45 V and 60 V respectively); substituting without circuit review risks overvoltage failure.
What does the "25" in BD37925STU signify?
The "25" in BD37925STU denotes the hFE classification group - specifically, hFE = 150–375 at IC = 1 A and VCE = 2 V. This distinguishes it from other BD379 variants (e.g., BD37916STU with hFE = 100–250), enabling precise gain binning for bias-critical linear applications.
Can BD37925STU be used in switching power supplies?
Yes, BD37925STU can be used in low-to-medium frequency switching power supplies (<200 kHz) where its tON = 50 ns and tOFF = 500 ns, VCE(sat) = 1 V, and SOA support are sufficient. However, modern MOSFETs or faster BJTs are preferred for >500 kHz operation due to limited switching speed and lack of integrated gate drive.
Does BD37925STU require a heatsink in typical operation?
Yes, BD37925STU requires a heatsink whenever power dissipation exceeds ~5–7 W continuously. With PC = 25 W at TC = 25°C and thermal resistance θJC ≈ 0.8°C/W (inferred from TO-126 construction), even 10 W dissipation raises junction temperature significantly - proper heatsinking maintains TJ < 150°C and ensures long-term reliability.
BD37925STU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-225AA, TO-126-3
- Packaging:
- Tube
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 2 A
- Voltage - Collector Emitter Breakdown (Max):
- 80 V
- Vce Saturation (Max) @ Ib, Ic:
- 1V @ 100mA, 1A
- Current - Collector Cutoff (Max):
- 2µA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 150 @ 150mA, 2V
- Power - Max:
- 25 W
- Frequency - Transition:
- -
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-126-3
BD37925STU FAQ
1.How can I place an order for BD37925STU through Aetrix?
Please submit a Request for Quotation (RFQ) for BD37925STU 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 BD37925STU reliable?
The price and inventory of BD37925STU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD37925STU is usually 5 days.
3.What payment methods are accepted for BD37925STU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD37925STU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BD37925STU?
BD37925STU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BD37925STU 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 BD37925STU?
For technical support, including BD37925STU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD37925STU requirements.
6.How does Aetrix verify that BD37925STU is sourced from the original manufacturer or authorized distributors?
All BD37925STU 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 BD37925STU meets industry standards.
7.What is the process for return or replacement of BD37925STU?
All BD37925STU units undergo pre-shipment inspection (PSI). If there is an issue with BD37925STU, 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 BD37925STU part is unused and in its original packaging.
Return procedure for BD37925STU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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