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onsemi MMBTA42LT3
- Part No.:
- MMBTA42LT3
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBTA42LT3.pdf
- Description:
- TRANS NPN 300V 0.5A SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,328
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Product details
Overview
MMBTA42LT3 from onsemi is an NPN silicon high-voltage general-purpose transistor in SOT-23 package, rated for 300 VCEO, 500 mA continuous collector current, and 225 mW power dissipation on FR-5 board; it delivers hFE ≥ 25 at 1 mA, VCE(sat) ≤ 0.5 V at IC/IB = 10, and fT = 50 MHz, commonly used in high-voltage switching and interface driver circuits.
For engineers reviewing the MMBTA42LT3 datasheet, pinout, applications, or equivalent options, key selection criteria include its 300 V breakdown rating, SOT-23 thermal performance on FR-5 vs. alumina substrates, DC gain behavior across 0.1–100 mA, saturation voltage under defined drive conditions, and automotive-grade AEC-Q101 qualification status.
Technical Context
This NPN bipolar junction transistor operates in active, saturation, and cutoff regions with verified V(BR)CEO = 300 V and V(BR)CBO = 300 V under pulsed test conditions (300 µs, 2% duty cycle). Its fT = 50 MHz at IC = 10 mA, VCE = 20 V enables use in medium-frequency switching and analog amplification up to ~10 MHz.
Thermal design requires attention to RJA = 556 °C/W on FR-5 board and 417 °C/W on alumina substrate; derating is 1.8 mW/°C above 25°C on FR-5 and 2.4 mW/°C on alumina. Junction temperature range is −55°C to +150°C, supporting industrial and automotive ambient environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 300 V - supports high-side switching in 200–250 V DC bus applications without avalanche stress |
| IC (continuous) | 500 mA - sufficient for driving relays, small solenoids, or logic-level interface loads |
| hFE (min) | 25 at IC = 1 mA - ensures reliable base-driven switching with low gate/base drive current |
| VCE(sat) | ≤ 0.5 V at IC = 20 mA, IB = 2 mA - minimizes conduction loss in saturated-switching configurations |
| fT | 50 MHz - enables stable operation in pulse-width modulation (PWM) control up to ~5–10 MHz |
| Ccb | 3.0 pF at VCB = 20 V - limits Miller effect in high-speed switching, reducing turn-off delay |
| RJA (FR-5) | 556 °C/W - defines maximum allowable power at ambient temperature; e.g., 150 mW max at TA = 70°C |
Pinout & Package
SOT-23 (TO-236) surface-mount package, 2.90 × 1.30 × 1.00 mm, 3-pin, lead-free and RoHS compliant. Pin configuration follows Style 6 per onsemi mechanical drawing: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Base | Current-controlled input node; requires series resistor to limit IB and ensure saturation at target IC |
| 2 | Emitter | Common reference terminal; connected to ground or low-side return path in common-emitter configuration |
| 3 | Collector | High-voltage output node; handles up to 300 V transient spikes when properly clamped and driven |
Key Features
| Feature | Design Value |
|---|---|
| 300 V VCEO rating | Enables direct replacement of older 200 V transistors (e.g., MMBTA43L) in legacy high-voltage interface designs |
| AEC-Q101 qualified | Validated for automotive body electronics, HVAC actuators, and lighting control where reliability over temperature cycling is critical |
| Pb-free, Halogen-free/BFR-free | Meets global environmental compliance requirements including RoHS Directive 2011/65/EU and JEDEC J-STD-609 |
| Low Ccb (3.0 pF) | Reduces capacitive coupling between collector and base, improving switching speed and noise immunity in PWM drivers |
| Wide TJ range (−55°C to +150°C) | Supports operation in under-hood automotive modules and industrial motor-control enclosures without derating below −40°C |
Applications
| Industrial Relay Drivers | Automotive LED Headlamp Switching |
|---|---|
Use Scenario: Driving 24 V DC coil relays in programmable logic controllers with microcontroller GPIO outputs. IC Role / Device Role / Timing Role: NPN switch providing current gain and voltage isolation between low-voltage logic and inductive load. Use Value: 300 V VCEO withstands relay coil flyback transients up to 250 V, eliminating need for external snubbers in many cases. |
Use Scenario: High-side switching of LED strings in adaptive front-lighting systems (AFS), controlled by CAN-linked microcontrollers. IC Role / Device Role / Timing Role: Medium-power discrete switch enabling PWM dimming at 1–10 kHz with fast turn-on/turn-off. Use Value: 50 MHz fT and low VCE(sat) reduce switching losses and thermal rise during 100% duty-cycle operation. |
| AC Line Sensing Interfaces | High-Voltage Logic Level Translation |
Use Scenario: Zero-crossing detection and AC mains monitoring in smart energy meters and appliance controllers. IC Role / Device Role / Timing Role: Voltage-scaled interface transistor isolating 120/230 V AC inputs from 3.3 V MCU inputs via resistive divider. Use Value: 300 V VCBO allows safe operation with peak line voltages up to 340 V without breakdown risk. |
Use Scenario: Converting 5 V TTL or 3.3 V CMOS logic signals to drive 12–24 V peripheral enable lines in industrial I/O modules. IC Role / Device Role / Timing Role: Single-transistor level shifter with current gain, replacing dual-MOSFET solutions in cost-sensitive designs. Use Value: hFE ≥ 25 at 1 mA ensures full saturation with <100 µA base drive, minimizing MCU port loading. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN high-voltage switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBTA43LT3G | Lower VCEO = 200 V; identical SOT-23 package, pinout, and thermal specs | Not suitable for >220 V DC or 300 V peak AC applications; acceptable in 12–48 V industrial controls | Select MMBTA43LT3G only if system voltage remains ≤200 V; otherwise MMBTA42LT3 provides necessary margin. |
| ZTX653STZ | Higher IC = 1 A, VCEO = 300 V, but in SOT-89 package (larger footprint, better thermal dissipation) | Requires PCB layout change; preferred where >500 mA load current or >300 mW power dissipation is needed | Choose ZTX653STZ when thermal budget exceeds SOT-23 capability or higher current headroom is required. |
Compared with MMBTA43LT3G, the MMBTA42LT3 offers 50% higher voltage margin for flyback suppression; compared with ZTX653STZ, it retains SOT-23 compatibility but trades off current capacity and thermal headroom for space-constrained layouts.
Availability
MMBTA42LT3 is available at Aetrix Electronics and suitable for industrial relay drivers, automotive LED switching, AC line sensing interfaces, and high-voltage logic level translation requiring stable component supply and long-term production continuity.
Supply support for MMBTA42LT3 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 MMBTA42LT3 belongs to onsemi's high-voltage bipolar transistor family designed for robust, cost-effective switching in automotive body electronics, industrial controls, and AC/DC interface circuits.
FAQ
What is the maximum continuous collector current rating for the MMBTA42LT3?
The MMBTA42LT3 has a maximum continuous collector current (IC) rating of 500 mA at TA = 25°C on FR-5 board. Derating applies above 25°C (1.8 mW/°C), and actual usable current depends on PCB layout, ambient temperature, and thermal management. The MMBTA42LT3 must not exceed this limit to maintain reliability and avoid thermal runaway.
Is the MMBTA42LT3 AEC-Q101 qualified?
Yes, the MMBTA42LT3 is AEC-Q101 qualified and PPAP capable, as confirmed in the official onsemi datasheet (Rev. 14, October 2024). This qualification covers stress testing for temperature cycling, humidity, mechanical shock, and electrical parameters, making the MMBTA42LT3 suitable for automotive body electronics and under-hood applications where reliability is critical.
What is the pin configuration of the MMBTA42LT3 in the SOT-23 package?
The MMBTA42LT3 uses Style 6 pinout in the SOT-23 (TO-236) package: Pin 1 is Base, Pin 2 is Emitter, and Pin 3 is Collector. This configuration is explicitly documented in the onsemi mechanical drawings and matches the marking diagram showing "1D" orientation with base-first identification. It is not pin-compatible with Style 7 or other SOT-23 variants.
Can the MMBTA42LT3 replace the MMBTA43LT3G in existing designs?
The MMBTA42LT3 can replace the MMBTA43LT3G in most designs where voltage margin is critical, since both share identical SOT-23 packaging, pinout, and thermal characteristics-but the MMBTA42LT3 offers 300 V VCEO versus 200 V for the MMBTA43LT3G. No PCB changes are needed, but verify that the higher voltage rating does not introduce unintended timing or gain effects in feedback loops.
What is the typical current-gain bandwidth product (fT) of the MMBTA42LT3?
The MMBTA42LT3 has a typical current-gain bandwidth product (fT) of 50 MHz, measured at IC = 10 mA, VCE = 20 V, and f = 100 MHz. This value indicates usable small-signal amplification up to ~10 MHz and supports clean switching in PWM applications below 5 MHz. The MMBTA42LT3 fT is stable across −55°C to +150°C per onsemi's typical characteristics curves.
MMBTA42LT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 500 mA
- Voltage - Collector Emitter Breakdown (Max):
- 300 V
- Vce Saturation (Max) @ Ib, Ic:
- 500mV @ 2mA, 20mA
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 40 @ 30mA, 10V
- Power - Max:
- 225 mW
- Frequency - Transition:
- 50MHz
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3 (TO-236)
MMBTA42LT3 FAQ
1.How can I place an order for MMBTA42LT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBTA42LT3 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 MMBTA42LT3 reliable?
The price and inventory of MMBTA42LT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBTA42LT3 is usually 5 days.
3.What payment methods are accepted for MMBTA42LT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBTA42LT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBTA42LT3?
MMBTA42LT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBTA42LT3 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 MMBTA42LT3?
For technical support, including MMBTA42LT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBTA42LT3 requirements.
6.How does Aetrix verify that MMBTA42LT3 is sourced from the original manufacturer or authorized distributors?
All MMBTA42LT3 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 MMBTA42LT3 meets industry standards.
7.What is the process for return or replacement of MMBTA42LT3?
All MMBTA42LT3 units undergo pre-shipment inspection (PSI). If there is an issue with MMBTA42LT3, 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 MMBTA42LT3 part is unused and in its original packaging.
Return procedure for MMBTA42LT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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