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NXP Semiconductors BF420,112
- Part No.:
- BF420,112
- Manufacturer:
- NXP Semiconductors
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
BF420,112.pdf
- Description:
- TRANS NPN 300V 0.05A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:5,247
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Product details
Overview
BF420,112 from NXP Semiconductors is an NPN high-voltage transistor in a TO-92 (SOT54/SC-43A) plastic through-hole package, rated for 300 V collector-base and collector-emitter voltage, 830 mW power dissipation at 25 °C ambient, 1.6 pF feedback capacitance, and 60 MHz transition frequency. It serves as a video output stage switch in colour TV and professional monitor systems.
For engineers reviewing the BF420,112 datasheet, BF420,112 pinout, BF420,112 application, or BF420,112 equivalent, key selection criteria include high-voltage switching capability (VCBO = 300 V), low feedback capacitance (Cre ≤ 1.6 pF), DC current gain (hFE ≥ 50 at IC = 25 mA), thermal resistance (Rth(j-a) = 150 K/W), and compatibility with Class-B video output topologies.
Technical Context
The BF420,112 operates as a high-voltage NPN switching transistor optimized for video-frequency amplification where low capacitive coupling and stable gain at moderate currents are critical. Its design targets open-base (VCEO = 300 V) and open-emitter (VCBO = 300 V) breakdown robustness, with specified hFE ≥ 50 at VCE = 20 V and IC = 25 mA.
Thermal performance is defined for PCB-mounted operation (Rth(j-a) = 150 K/W), and its 1.6 pF Cre ensures minimal Miller-effect distortion in high-speed video driver stages. The device supports peak collector currents up to 100 mA and operates within junction temperature limits of 150 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCBO | 300 V - maximum collector-base voltage with emitter open; enables safe operation in high-voltage video sweep and output circuits |
| VCEO | 300 V - maximum collector-emitter voltage with base open; supports Class-B video output stage biasing without breakdown |
| Cre | 1.6 pF - feedback capacitance at VCE = 30 V; minimizes signal phase shift and instability in wideband video amplifiers |
| fT | 60 MHz - transition frequency at VCE = 10 V, IC = 10 mA; confirms usable gain up to VHF video frequencies |
| Ptot | 830 mW - total power dissipation at Tamb ≤ 25 °C; defines thermal derating envelope for continuous video output duty cycles |
| hFE | ≥50 - DC current gain at VCE = 20 V, IC = 25 mA; ensures reliable base drive efficiency in linear and switching video stages |
| Rth(j-a) | 150 K/W - junction-to-ambient thermal resistance on PCB; determines required copper area and airflow for thermal management |
Pinout & Package
Package: TO-92 plastic single-ended leaded (through-hole) package, also designated SC-43A and SOT54; 3-lead, axial-leaded, epoxy-molded housing with standard mounting footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Base | Control electrode; accepts base current to enable collector-emitter conduction; requires current-limiting resistor in linear video driver applications |
| 2 | Collector | High-voltage output node; connected to video load (e.g., deflection yoke or CRT anode circuit); must withstand 300 V transients |
| 3 | Emitter | Reference terminal; typically grounded or tied to low-impedance return path; carries full collector current in Class-B operation |
Key Features
| Feature | Design Value |
|---|---|
| Low feedback capacitance | Cre ≤ 1.6 pF reduces Miller effect, preserving bandwidth and phase margin in video amplifier feedback loops |
| High-voltage rating | VCBO/VCEO = 300 V supports direct interface with CRT anode supplies and horizontal deflection circuits |
| Stable DC current gain | hFE ≥ 50 at IC = 25 mA ensures predictable base drive requirements across production lots |
| TO-92 mechanical compatibility | SOT54 outline enables drop-in replacement in legacy TV and monitor PCBs designed for standard through-hole transistors |
Applications
| Colour Television Video Output | Professional Monitor Deflection |
|---|---|
Use Scenario: Driving horizontal deflection yoke and CRT anode in analogue colour TV receivers. IC Role / Device Role / Timing Role: NPN high-voltage switch in Class-B video output stage; handles repetitive 15.625 kHz flyback pulses with 300 V peak swing. Use Value: 300 V VCEO and low Cre prevent saturation delay and waveform distortion during fast retrace transitions. | Use Scenario: Amplifying sync-synchronized video signals in broadcast-grade RGB monitors. IC Role / Device Role / Timing Role: Linear video output transistor delivering low-distortion, high-slew-rate signals to CRT grid or cathode. Use Value: 60 MHz fT and hFE ≥ 50 maintain flat frequency response across 5–7 MHz video bandwidth. |
| Video Signal Switching | High-Voltage Pulse Generation |
Use Scenario: Selecting between multiple video sources in composite/S-Video routing hardware. IC Role / Device Role / Timing Role: High-voltage analog switch controlling signal path continuity under 1–5 V control logic. Use Value: Low Cre (≤1.6 pF) minimizes crosstalk and transient feedthrough during switching transitions. | Use Scenario: Generating calibrated high-voltage pulses for test equipment calibration and CRT focus adjustment. IC Role / Device Role / Timing Role: Fast-switching NPN transistor triggered by TTL-level pulses to produce 300 V, sub-µs rise-time outputs. Use Value: 100 mA ICM and 830 mW Ptot allow short-duration pulse bursts without thermal runaway. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN high-voltage transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BF422,112 | Lower VCBO/VCEO (250 V vs. 300 V); otherwise identical pinout, Cre, fT, and package | Not suitable for 300 V video output stages; limited to lower-voltage deflection or auxiliary supply circuits | Select BF422,112 only when system voltage stress remains below 250 V; verify flyback margin in CRT designs |
| BC639,112 | Lower VCBO/VCEO (80 V), higher hFE (40–250), same TO-92 package but not high-voltage rated | Applicable only in low-voltage video pre-amplifier or logic interface stages-not for primary output switching | Use BC639,112 for general-purpose amplification where voltage stress < 80 V; avoid in CRT anode or deflection paths |
Compared with BF420,112, BF422,112 offers identical form factor and gain but reduced voltage headroom, while BC639,112 trades voltage capability for higher DC gain and broader hFE distribution-neither is a drop-in replacement for 300 V video output use.
Availability
BF420,112 is available at Aetrix Electronics and suitable for colour television repair, professional monitor manufacturing, and high-voltage pulse generator development requiring stable component supply and long-term obsolescence support.
Supply support for BF420,112 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
NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in high-performance analog, logic, and RF components for industrial, automotive, and consumer electronics.
The BF420,112 belongs to NXP's legacy discrete transistor product line, engineered specifically for high-voltage video signal processing and CRT-based display systems requiring rugged, low-capacitance switching performance.
FAQ
What is the maximum collector-emitter voltage rating for BF420,112?
The BF420,112 has a maximum collector-emitter voltage (VCEO) rating of 300 V with the base open. This specification is verified per IEC 60134 limiting values and applies under standard PCB mounting conditions. Exceeding this voltage risks permanent junction breakdown. The BF420,112 is therefore suited for CRT anode drive and horizontal deflection circuits where peak voltages approach but do not exceed 300 V.
Is BF420,112 pin-compatible with BF422,112?
Yes, BF420,112 and BF422,112 share identical TO-92 (SOT54) pinout: Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter. However, BF422,112 is rated for only 250 V VCEO/VCBO, so physical compatibility does not imply functional interchangeability in 300 V applications. Always validate voltage stress margins before substitution.
What is the typical transition frequency (fT) of BF420,112 and how is it measured?
The BF420,112 has a minimum transition frequency (fT) of 60 MHz, measured under standardized conditions: VCE = 10 V, IC = 10 mA, and test frequency = 100 MHz. This parameter reflects the frequency at which small-signal current gain drops to unity and confirms suitability for VHF video signal amplification up to ~5 MHz with adequate gain margin.
Does BF420,112 have a PNP complement, and if so, what is it?
Yes, the PNP complement to BF420,112 is BF421,112. Both devices share matching voltage ratings (300 V VCBO/VCEO), thermal characteristics, and TO-92 packaging. BF421,112 is intended for complementary Class-B or push-pull video output configurations where symmetrical high-voltage switching is required.
What is the thermal resistance from junction to ambient (Rth(j-a)) for BF420,112?
The thermal resistance from junction to ambient (Rth(j-a)) for BF420,112 is 150 K/W, specified for PCB-mounted operation per manufacturer data. This value assumes standard copper land patterns and still-air conditions. To maintain junction temperature ≤150 °C, power dissipation must be derated above 25 °C ambient using this thermal coefficient.
BF420,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 50 mA
- Voltage - Collector Emitter Breakdown (Max):
- 300 V
- Vce Saturation (Max) @ Ib, Ic:
- 600mV @ 5mA, 30mA
- Current - Collector Cutoff (Max):
- 10nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 50 @ 25mA, 20V
- Power - Max:
- 830 mW
- Frequency - Transition:
- 60MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
BF420,112 FAQ
1.How can I place an order for BF420,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for BF420,112 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 BF420,112 reliable?
The price and inventory of BF420,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BF420,112 is usually 5 days.
3.What payment methods are accepted for BF420,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BF420,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BF420,112?
BF420,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BF420,112 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 BF420,112?
For technical support, including BF420,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BF420,112 requirements.
6.How does Aetrix verify that BF420,112 is sourced from the original manufacturer or authorized distributors?
All BF420,112 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 BF420,112 meets industry standards.
7.What is the process for return or replacement of BF420,112?
All BF420,112 units undergo pre-shipment inspection (PSI). If there is an issue with BF420,112, 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 BF420,112 part is unused and in its original packaging.
Return procedure for BF420,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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