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ROHM Semiconductor |
TRANS PREBIAS NPN 200MW SMT3 |
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ROHM Semiconductor |
TRANS PREBIAS NPN 300MW SPT |
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ROHM Semiconductor |
TRANS PREBIAS NPN 300MW SPT |
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ROHM Semiconductor |
TRANS PREBIAS NPN 300MW SPT |
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ROHM Semiconductor |
TRANS PNP 100MA 50V SOT-416FL |
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ROHM Semiconductor |
TRANS PREBIAS PNP 300MW SPT |
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ROHM Semiconductor |
TRANS PREBIAS NPN 200MW SMT3 |
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ROHM Semiconductor |
TRANS PREBIAS NPN 300MW SPT |
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ROHM Semiconductor |
TRANS NPN 100MA 50V SC-89 |
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ROHM Semiconductor |
TRANS PREBIAS PNP 300MW SPT |
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ROHM Semiconductor |
TRANS PREBIAS PNP 300MW SPT |
0 |
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ROHM Semiconductor |
TRANS PREBIAS PNP 300MW SPT |
0 |
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ROHM Semiconductor |
TRANS PREBIAS NPN 300MW SPT |
0 |
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ROHM Semiconductor |
TRANS PNP 100MA 50V SC-89 |
0 |
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ROHM Semiconductor |
TRANS PREBIAS NPN 300MW SPT |
0 |
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ROHM Semiconductor |
TRANS PREBIAS PNP 300MW SPT |
0 |
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ROHM Semiconductor |
TRANS PREBIAS NPN 300MW SPT |
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ROHM Semiconductor |
TRANS DGTL NPN 200MA SOT-346 |
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Pre-biased bipolar junction transistors (BJTs) are discrete semiconductor devices with integrated biasing resistors, designed to simplify circuit design and improve operational stability. Unlike standard BJTs requiring external biasing components, pre-biased BJTs incorporate internal resistors to set the base-emitter voltage and collector current. These devices are critical in modern electronics for applications demanding compact design, consistent performance, and reduced component count. Their ability to maintain stable operation under varying temperature and voltage conditions makes them essential in consumer electronics, industrial automation, and automotive systems.
| Type | Functional Features | Application Examples |
|---|---|---|
| NPN Pre-Biased BJT | Positive bias resistor network, low-side switching | Logic-level switching, LED drivers |
| PNP Pre-Biased BJT | Negative bias resistor network, high-side switching | Power supply control, relay drivers |
| Digital Transistor | Integrated resistors with ESD protection | Digital logic circuits, portable devices |
Pre-biased BJTs consist of a silicon semiconductor die with three doped regions (emitter, base, collector) forming two p-n junctions. The key structural elements include: - Monolithic Resistor Network: Thin-film or diffused resistors embedded in the die for fixed biasing - Metal Contacts: Aluminum or copper layers for external connections - Encapsulation: Plastic or ceramic packaging with standard pinouts (e.g., SOT-23, TO-92) - Passivation Layer: Silicon dioxide/nitride coating to prevent surface contamination
| Parameter | Description | Importance |
|---|---|---|
| Current Gain (hFE) | Ratio of collector to base current | Determines amplification capability |
| Max Collector Voltage (VCEO) | Max voltage across collector-emitter | Defines operating voltage range |
| Transition Frequency (fT) | Frequency response limit | Critical for RF and switching applications |
| Power Dissipation (Ptot) | Max thermal power handling | Dictates thermal management needs |
| Built-in Resistor Ratio (R1/R2) | Internal resistor division ratio | Controls bias point stability |
Main industries and typical equipment: - Consumer Electronics: Mobile phone chargers, wearable devices - Industrial Automation: PLC modules, motor drivers - Automotive: Sensor interfaces, LED lighting systems - Telecommunications: Base station power amplifiers - Power Management: DC-DC converter switches
| Manufacturer | Key Products | Features |
|---|---|---|
| ON Semiconductor | MMBT3904L | 200mA NPN transistor with 47k bias resistors |
| Toshiba | 2SB1958 | PNP device with built-in 10k /4.7k resistor network |
| STMicroelectronics | SM6T120N | Automotive-grade digital transistor with ESD protection |
Key considerations: - Match hFE with required amplification/saturation characteristics - Confirm VCEO rating exceeds circuit voltage requirements - Select resistor ratios for desired bias point (e.g., R1=10k , R2=22k for mid-range bias) - Prioritize thermal performance in high-power applications - Consider package type (SMD vs. through-hole) for PCB constraints
Emerging trends include: - Miniaturization: Development of 0.4mm pitch WLCSP packages - Integrated protection: ESD/clamp diodes in standard designs - High-frequency variants: fT > 5GHz for 5G infrastructure - Automotive qualification: Increased demand for AEC-Q101 certified devices - Green manufacturing: Lead-free packaging and low-toxicity materials