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onsemi BUB323ZT4
- Part No.:
- BUB323ZT4
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-263-3, D2PAK (2 Leads + Tab), TO-263AB
- Datasheet:
-
BUB323ZT4.pdf
- Description:
- TRANS NPN DARL 350V 10A D2PAK
- Quantity:
- Payment:
- Shipping:
Inventory:8,143
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Product details
Overview
BUB323ZT4 from onsemi is an NPN silicon power Darlington transistor with integrated active zener clamping, rated for 350 VCEO, 10 A continuous collector current, and 150 W power dissipation in D2PAK (Case 418B) package. It is engineered for unclamped inductive switching in automotive electronic ignition systems, motor control circuits, and switching regulators requiring robust avalanche energy handling.
For engineers reviewing the BUB323ZT4 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage window (350–450 V), guaranteed repetitive clamp energy (200 mJ), SOA compliance at all temperatures, AEC-Q101 qualification, and D2PAK thermal resistance (RθJC = 1.0 °C/W).
Technical Context
The BUB323ZT4 implements a planar monolithic Darlington structure with built-in active zener clamping circuitry that triggers at 350–450 V to prevent reverse-bias operating limit failure during inductive turn-off. Its IC = f(VCE) curve exhibits a distinctive shape due to coordinated high-voltage driver and avalanche diode activation.
It operates within a −65°C to +175°C junction temperature range, maintains DC current gain (hFE) from 150 to 3400 across −40°C to +125°C, and sustains 200 mJ repetitive clamping energy in live ignition test conditions (IC = 7.0 A, L = 8.0 mH, RBE = 100 Ω) - 100% tested per Figures 2 and 4 of the datasheet.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 350 Vdc - Maximum sustaining voltage before clamping activation; defines safe blocking capability in unclamped inductive loads. |
| IC (continuous) | 10 Adc - Continuous collector current rating at TC = 25°C; supports sustained motor drive or regulator output stages. |
| VCLAMP | 350–450 Vdc - Guaranteed clamping window over −40°C to +125°C; enables predictable voltage limiting without external snubbers. |
| WCLAMP | 200 mJ - Minimum repetitive non-destructive energy dissipated at turn-off; validated in live ignition circuit per Figure 2. |
| RθJC | 1.0 °C/W - Junction-to-case thermal resistance; allows direct heatsink mounting for high-power dissipation up to 150 W. |
| hFE | 150–3400 - DC current gain across full temperature and current range; ensures reliable base drive efficiency in automotive environments. |
| tfi | 625 ns - Typical fall time under inductive load (L = 10 mH); enables fast switching in ignition coil drivers. |
Pinout & Package
D2PAK (Case 418B) 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 Darlington pair; requires ≥100 mA peak drive for full saturation at 10 A IC. |
| 2 | Collector | Main high-voltage current path terminal; electrically tied to Pin 4 for parallel conduction and reduced thermal resistance. |
| 3 | Emitter | Power return node; referenced for VBE(sat) and clamping threshold; connects to ground or low-side switch node. |
| 4 | Collector | Second collector terminal; shares internal die connection with Pin 2 to distribute current and improve thermal spreading to heatsink. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated active zener clamp | Eliminates need for external snubber networks in ignition and motor control, reducing BOM count and PCB area. |
| Tight 350–450 V clamping window | Ensures consistent overvoltage protection across automotive temperature extremes without derating or calibration. |
| 100% live-circuit energy testing | Each unit verified for 200 mJ repetitive clamping energy in actual ignition test setup (IC = 7.0 A, L = 8.0 mH), not just parametric screening. |
| AEC-Q101 qualified + PPAP capable | Validated for automotive under-hood applications including engine control modules and starter solenoid drivers. |
| Dual-collector D2PAK thermal design | Enables 150 W dissipation with RθJC = 1.0 °C/W; dual collector pins reduce current density and improve reliability under surge conditions. |
Applications
| Automotive Electronic Ignition | Industrial Motor Control |
|---|---|
Use Scenario: Driving primary winding of distributorless ignition coils in gasoline engines under wide ambient temperature and battery voltage variation. IC Role / Device Role / Timing Role: High-voltage, high-current switch controlling coil energization and controlled turn-off with active clamping. Use Value: Eliminates external clamping diodes while guaranteeing 200 mJ repetitive energy handling - critical for spark timing consistency and coil longevity. |
Use Scenario: Controlling brushed DC motors in HVAC actuators, valve positioners, and conveyor drives where inductive kickback must be managed without snubbers. IC Role / Device Role / Timing Role: Low-side power switch with integrated overvoltage protection during PWM commutation and emergency stop events. Use Value: Maintains 350–450 V clamping window across −40°C to +125°C, ensuring reliable operation in industrial enclosures without thermal derating. |
| Switching Regulator Output Stage | High-Voltage Solenoid Driver |
Use Scenario: Output switch in offline flyback or forward converters delivering >100 W with 300+ VDC bus voltages. IC Role / Device Role / Timing Role: Primary-side power switch managing energy transfer and absorbing leakage inductance spikes. Use Value: Built-in clamp replaces discrete TVS + RC snubber, reducing component count and improving EMI performance by limiting dV/dt overshoot. |
Use Scenario: Driving 24 V or 48 V solenoids in heavy-duty machinery, agricultural equipment, and railway braking systems. IC Role / Device Role / Timing Role: Robust interface between microcontroller GPIO and high-inductance load, handling >10 A surges during pull-in. Use Value: Dual-collector D2PAK construction supports 10 A continuous and 20 A peak current while maintaining <2.1 V VCE(sat) at 10 A/0.25 A drive. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage Darlington switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STGD3HF60D | MOSFET-based high-voltage switch (600 V, 3 A), no integrated clamp; requires external TVS or RCD network. | Lower gate drive complexity but higher system-level BOM cost and layout sensitivity for clamping. | Select when lower switching losses and higher frequency (>20 kHz) operation are required; not drop-in for BUB323ZT4's Darlington drive architecture. |
| BU931ZT4 | Same manufacturer, same D2PAK package, but rated for 400 VCEO, 15 A, and 200 W; clamping window 400–500 V. | Higher voltage/current capability; broader SOA but larger footprint and higher cost. | Select when system bus voltage exceeds 350 V or peak current exceeds 10 A; pinout and footprint identical, enabling direct upgrade path. |
Compared with STGD3HF60D and BU931ZT4, the BUB323ZT4 offers optimal balance of integrated protection, automotive qualification, and thermal performance for 350 V-class ignition and motor control - avoiding external clamps while maintaining compatibility with legacy D2PAK layouts.
Availability
BUB323ZT4 is available at Aetrix Electronics and suitable for automotive electronic ignition systems, industrial motor controllers, and switching regulator output stages requiring stable component supply and long-term lifecycle support.
Supply support for BUB323ZT4 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 management, analog, sensor, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.
The BUB323ZT4 belongs to onsemi's Autoprotected Darlington family, designed specifically for ruggedized inductive switching in harsh automotive and industrial environments where reliability under voltage transients is mission-critical.
FAQ
What is the clamping voltage range of the BUB323ZT4, and is it guaranteed across temperature?
The BUB323ZT4 has a guaranteed clamping voltage range of 350 V to 450 V, explicitly specified over the full operating junction temperature range of −40°C to +125°C. This tight window is ensured by onsemi's integrated active zener clamping circuit and is 100% tested per the live ignition circuit conditions described in the datasheet (Figure 2). The BUB323ZT4 maintains this behavior without external components, making it suitable for automotive under-hood applications where thermal stability is essential.
Is the BUB323ZT4 pin-compatible with other D2PAK Darlington transistors like the BU931ZT4?
Yes, the BUB323ZT4 uses the standard D2PAK (Case 418B) package with identical pinout: Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter, Pin 4 = Collector. It shares mechanical and electrical footprint compatibility with BU931ZT4, allowing direct PCB replacement in many designs. However, the BUB323ZT4 is rated for 350 VCEO and 10 A, whereas BU931ZT4 is rated for 400 VCEO and 15 A - verify voltage margin and thermal design before substitution.
Does the BUB323ZT4 require external base resistors or clamping components?
No, the BUB323ZT4 integrates both active zener clamping and Darlington drive circuitry, eliminating the need for external clamping diodes or snubber networks in most inductive switching applications. A base resistor is still required to limit IB (e.g., 100 mA peak), but no external TVS, Zener, or RC network is needed for voltage protection. This simplifies design and improves reliability in automotive ignition and motor control systems using the BUB323ZT4.
What is the maximum repetitive clamping energy rating for the BUB323ZT4, and how is it validated?
The BUB323ZT4 is rated for 200 mJ of repetitive non-destructive clamping energy, validated using the standardized live ignition test circuit (Figure 2) with IC = 7.0 A, L = 8.0 mH, and RBE = 100 Ω. Every unit undergoes 100% production testing under these conditions - not just parametric sampling - ensuring each BUB323ZT4 can sustain repeated inductive turn-off events without degradation of electrical parameters or SOA compliance.
Is the BUB323ZT4 suitable for new automotive designs despite its "DISCONTINUED" status in some ordering variants?
While the base part BUB323ZG is marked discontinued, the NJVBUB323ZT4G* variant - which includes the BUB323ZT4 - remains actively supported for automotive applications: it carries the NJV prefix, is AEC-Q101 qualified, and is PPAP capable. onsemi confirms this variant is intended for new designs requiring unique site and control change requirements. Customers should specify NJVBUB323ZT4G* to ensure long-term supply and automotive-grade traceability for the BUB323ZT4.
BUB323ZT4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-263-3, D2PAK (2 Leads + Tab), TO-263AB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Transistor Type:
- NPN - Darlington
- Current - Collector (Ic) (Max):
- 10 A
- Voltage - Collector Emitter Breakdown (Max):
- 350 V
- Vce Saturation (Max) @ Ib, Ic:
- 1.7V @ 250mA, 10A
- Current - Collector Cutoff (Max):
- 100µA
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 500 @ 5A, 4.6V
- Power - Max:
- 150 W
- Frequency - Transition:
- 2MHz
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- D2PAK
BUB323ZT4 FAQ
1.How can I place an order for BUB323ZT4 through Aetrix?
Please submit a Request for Quotation (RFQ) for BUB323ZT4 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 BUB323ZT4 reliable?
The price and inventory of BUB323ZT4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUB323ZT4 is usually 5 days.
3.What payment methods are accepted for BUB323ZT4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUB323ZT4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BUB323ZT4?
BUB323ZT4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BUB323ZT4 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 BUB323ZT4?
For technical support, including BUB323ZT4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUB323ZT4 requirements.
6.How does Aetrix verify that BUB323ZT4 is sourced from the original manufacturer or authorized distributors?
All BUB323ZT4 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 BUB323ZT4 meets industry standards.
7.What is the process for return or replacement of BUB323ZT4?
All BUB323ZT4 units undergo pre-shipment inspection (PSI). If there is an issue with BUB323ZT4, 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 BUB323ZT4 part is unused and in its original packaging.
Return procedure for BUB323ZT4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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