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onsemi BUD42DG
- Part No.:
- BUD42DG
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
BUD42DG.pdf
- Description:
- TRANS NPN 350V 4A DPAK
- Quantity:
- Payment:
- Shipping:
Inventory:5,130
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Product details
Overview
BUD42DG from onsemi is a high-speed, high-gain bipolar NPN transistor with integrated antisaturation network and transient voltage suppression capability, rated for 650 VCEO, 4 A continuous collector current, and 25 W power dissipation in DPAK (Case 369C) package - designed for electronic light ballast circuits requiring robust switching under inductive load conditions.
For engineers reviewing the BUD42DG datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal behavior, safe operating area limits, dynamic saturation performance at 25°C/125°C, and real-world switching timing data under resistive and inductive loads - all critical for lamp driver design validation and reliability assurance.
Technical Context
The BUD42DG integrates a built-in free-wheeling diode and antisaturation network to minimize storage time and improve turn-off consistency across temperature. Its "6 Sigma" manufacturing ensures tight parameter spreads in hFE, VCE(sat), and switching times - essential for consistent light output in HID and fluorescent ballasts.
It operates with VCEO = 350 V (sustained), VCBO = 650 V, and supports peak collector current up to 8 A with base drive optimized for forced gain of 5–10. Dynamic saturation voltage is characterized at 1 µs and 3 µs post-IB rise, enabling accurate modeling of voltage overshoot during fast switching transitions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 350 Vdc - Sustaining voltage under inductive switching; defines maximum clamped off-state voltage in ballast flyback operation. |
| IC Continuous | 4.0 Adc - Maximum steady-state collector current; sets thermal design baseline for heatsink sizing in 25 W dissipation envelope. |
| VCE(sat) | 0.2–1.0 Vdc @ IC = 2 A, IB = 0.5 A - Low saturation voltage reduces conduction loss and improves efficiency in high-frequency lamp drivers. |
| toff | 4.6–6.55 µs @ IC = 1.2 A, VCC = 300 V - Fast, tightly distributed turn-off time enables stable 20–100 kHz ballast operation without oscillation. |
| RJC | 5.0 °C/W - Junction-to-case thermal resistance; allows direct calculation of junction temperature rise under known case temperature and power. |
| hFE | 8–13 @ IC = 1 A, VCE = 2 V - Flat DC current gain across operating range simplifies base drive design and improves line regulation. |
| VEC | 0.9–1.5 V @ IEC = 1.0 A - Forward diode voltage of integrated emitter-collector diode; enables self-commutated freewheeling without external diode. |
Pinout & Package
DPAK (Case 369C) surface-mount package with 4 terminals: Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter, Pin 4 = Collector (dual-collector configuration for enhanced current handling and thermal path).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Base | Control input for transistor switching; requires active base drive (IB ≤ 1.0 Adc continuous) to achieve specified forced gain and switching speed. |
| 2 | Collector | Main high-voltage current path; electrically tied to Pin 4; used for primary-side switching in half-bridge or resonant lamp driver topologies. |
| 3 | Emitter | Reference node for base-emitter bias and current sensing; connects to ground or low-side switch in standard ballast configurations. |
| 4 | Collector | Second collector terminal - paralleled internally with Pin 2 to reduce current density and improve thermal distribution across die and package. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated free-wheeling diode | Enables self-contained inductive energy recirculation without external diode - reduces BOM count and PCB footprint in compact ballast designs. |
| Flat hFE vs. IC | Maintains stable current gain from 0.1 A to 2 A, minimizing base drive variation and improving lamp current regulation across dimming ranges. |
| Tight switching time distribution | Turn-off time spread ≤ 1.95 µs (6.55 − 4.6 µs); ensures predictable timing margins in synchronous control schemes and reduces EMI variability. |
| Dynamic saturation voltage characterization | Specified VCE(dsat) at 1 µs and 3 µs post-IB rise - supports accurate simulation of voltage spikes during fast turn-on in high-dV/dt lamp ignition phases. |
| Pb-free, RoHS-compliant epoxy | UL 94 V-0 rated at 0.125 in thickness - meets safety and environmental requirements for commercial and industrial lighting equipment certifications. |
Applications
| Electronic Fluorescent Ballast (EFB) | HID Lamp Ignition Circuit |
|---|---|
Use Scenario: High-frequency (20–60 kHz) square-wave inverter driving T5/T8 lamps with preheat and run phases. IC Role / Device Role / Timing Role: Main switching transistor in half-bridge topology; handles 300–400 VDC bus with 2–4 A peak lamp current and fast zero-voltage switching transitions. Use Value: Integrated diode eliminates need for external freewheeling path; flat hFE ensures stable lamp current over temperature and line voltage variation. |
Use Scenario: Ignition pulse generation for metal halide and high-pressure sodium lamps using resonant voltage step-up and controlled current ramp. IC Role / Device Role / Timing Role: Primary-side switch in flyback or LCC resonant converter; sustains 650 V blocking while delivering 1–3 A ignition pulses with <7 µs turn-off. Use Value: 650 VCBO rating and tight toff distribution enable reliable ignition under varying ambient temperatures and aging conditions. |
| LED Driver with Inductive Energy Storage | Industrial Motor Control Starter |
Use Scenario: Constant-current LED driver using inductive buck-boost topology with high-side switching and PWM dimming. IC Role / Device Role / Timing Role: High-voltage switch controlling energy transfer into output inductor; operates at 100–500 kHz with 350 V blocking requirement. Use Value: Low VCE(sat) and fast toff reduce conduction and switching losses; dual-collector layout improves thermal management in sealed enclosures. |
Use Scenario: Soft-start circuit for small AC induction motors (≤1 kW), where inrush current limiting is achieved via controlled inductive discharge. IC Role / Device Role / Timing Role: Power switch in series with motor winding; clamps inductive kickback during turn-off using internal diode and RBSOA compliance. Use Value: Reverse Bias SOA validated up to 600 V and 4 A enables safe operation without snubber networks in cost-sensitive starter modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage bipolar transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STGD3HF60D | MOSFET (600 V, 3 A), no integrated diode, gate-driven; higher input impedance but requires external freewheeling diode and gate driver. | Lower switching losses above 100 kHz; unsuitable for linear-mode ballast operation due to lack of analog gain control. | Select when designing high-frequency (>150 kHz), low-duty-cycle LED drivers where gate drive simplicity outweighs need for analog gain. |
| MJD42CG | Bipolar NPN (600 V, 3 A), same DPAK package, no integrated diode, hFE = 10–25, toff ≈ 12 µs - slower and less consistent than BUD42DG. | Acceptable for lower-frequency (<30 kHz) magnetic ballast replacements; lacks dynamic saturation specs and tight timing distribution. | Choose only if cost sensitivity overrides need for precise timing control and integrated diode functionality in legacy redesigns. |
Compared with STGD3HF60D and MJD42CG, the BUD42DG uniquely combines integrated freewheeling diode, sub-7 µs turn-off, flat hFE, and dynamic saturation characterization - making it the only option qualified for high-reliability, high-frequency electronic ballast designs requiring minimal external components and predictable thermal behavior.
Availability
BUD42DG is available at Aetrix Electronics and suitable for electronic fluorescent ballasts, HID lamp igniters, LED drivers with inductive storage, and industrial motor starters requiring stable component supply, long-lifecycle support, and traceable Pb-free sourcing.
Supply support for BUD42DG 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 consumer markets.
The BUD42DG belongs to onsemi's high-voltage bipolar power transistor family engineered specifically for lighting control systems - emphasizing ruggedness under repetitive avalanche stress, tight parameter distribution, and integrated protection features for lamp driver reliability.
FAQ
What is the maximum continuous collector current rating for the BUD42DG?
The BUD42DG is rated for 4.0 Adc continuous collector current at TC = 25°C. Derating applies above 25°C at 0.2 W/°C, and the device supports 8.0 A peak current for short pulses (5 ms, 10% duty cycle). This rating directly informs heatsink selection and thermal design in lamp driver applications.
Does the BUD42DG include an integrated diode, and how is it configured?
Yes, the BUD42DG integrates a built-in free-wheeling diode between emitter and collector (VEC), with forward voltage 0.9–1.5 V at 1.0 A. It is not a separate Schottky but part of the transistor structure - enabling self-commutated inductive energy recovery without external components in ballast and motor starter circuits.
What is the significance of the "G" suffix in BUD42DG?
The "G" suffix in BUD42DG indicates a Pb-free, RoHS-compliant package per onsemi's marking convention. It confirms compliance with UL 94 V-0 flammability rating at 0.125 in thickness and verifies that the DPAK (Case 369C) molding compound meets environmental and safety standards for commercial lighting equipment.
How does the BUD42DG's dynamic saturation voltage differ from its DC VCE(sat)?
The BUD42DG specifies dynamic saturation voltage (VCE(dsat)) at 1 µs and 3 µs after base current rise - values range from 0.35 V to 4.7 V depending on IC, IB, and temperature. This differs from DC VCE(sat) (0.2–1.0 V) by capturing transient overvoltage during turn-on, critical for snubberless design in high-dV/dt lamp ignition.
Is the BUD42DG pin-compatible with other DPAK transistors like MJD42CG?
The BUD42DG uses DPAK (Case 369C) with Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter, Pin 4 = Collector - identical pinout to MJD42CG. However, functional compatibility requires verification of hFE, toff, and integrated diode presence; MJD42CG lacks both the diode and tight timing distribution of the BUD42DG.
BUD42DG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Packaging:
- Tube
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 4 A
- Voltage - Collector Emitter Breakdown (Max):
- 350 V
- Vce Saturation (Max) @ Ib, Ic:
- 1V @ 500mA, 2A
- Current - Collector Cutoff (Max):
- 100µA
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 10 @ 2A, 5V
- Power - Max:
- 25 W
- Frequency - Transition:
- -
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DPAK
BUD42DG FAQ
1.How can I place an order for BUD42DG through Aetrix?
Please submit a Request for Quotation (RFQ) for BUD42DG 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 BUD42DG reliable?
The price and inventory of BUD42DG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUD42DG is usually 5 days.
3.What payment methods are accepted for BUD42DG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUD42DG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BUD42DG?
BUD42DG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BUD42DG 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 BUD42DG?
For technical support, including BUD42DG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUD42DG requirements.
6.How does Aetrix verify that BUD42DG is sourced from the original manufacturer or authorized distributors?
All BUD42DG 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 BUD42DG meets industry standards.
7.What is the process for return or replacement of BUD42DG?
All BUD42DG units undergo pre-shipment inspection (PSI). If there is an issue with BUD42DG, 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 BUD42DG part is unused and in its original packaging.
Return procedure for BUD42DG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BUD42DG Tags
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MMBT3906LT1G
onsemi
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Nexperia USA Inc.
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