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onsemi BF423G
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- Part No.:
- BF423G
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 Long Body
- Datasheet:
-
BF423G.pdf
- Description:
- TRANS PNP 250V 0.5A TO92
- Quantity:
- Payment:
- Shipping:
Inventory:8,138
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Product details
Overview
BF423G from onsemi is a PNP silicon high-voltage transistor rated for −250 VCEO, −250 VCBO, and −5.0 VEBO, with continuous collector current of −500 mA and DC current gain (hFE) ≥50 at −25 mA/−20 V. It operates across −55°C to +150°C and is used in high-voltage switching and line-output stages in CRT-based displays and industrial power supplies.
For engineers reviewing the BF423G datasheet, pinout, applications, or equivalent options, key selection criteria include its −250 V breakdown rating, TO-92 package thermal resistance (RJA = 150°C/W), saturation voltage (VCE(sat) ≤ −0.5 V at −20 mA/−2.0 mA), and fT = 60 MHz - all critical for high-voltage linear and switching amplifier designs.
Technical Context
The BF423G is a discrete PNP bipolar junction transistor optimized for high-voltage, medium-current switching and amplification. Its structure supports stable operation up to 150°C junction temperature, with low leakage (ICBO ≤ −0.01 A, IEBO ≤ −100 nA) and defined saturation behavior (VBE(sat) ≤ −2.0 V at −20 mA/−2.0 mA).
It features a current-gain–bandwidth product of 60 MHz under standard test conditions (IC = −10 mA, VCE = −10 V, f = 20 MHz) and reverse transfer capacitance (Cre) of 2.8 pF at VCB = −30 V, making it suitable for RF-coupled high-voltage driver stages and horizontal deflection circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | −250 Vdc - maximum safe collector-emitter voltage before avalanche breakdown in common-emitter configuration |
| hFE | ≥50 at IC = −25 mA, VCE = −20 V - ensures reliable current amplification in linear and switching modes |
| VCE(sat) | ≤ −0.5 V at IC = −20 mA, IB = −2.0 mA - minimizes conduction loss in saturated switch applications |
| fT | 60 MHz - enables use in high-frequency signal amplification up to VHF range in tuned circuits |
| RJA | 150°C/W - defines thermal derating on FR4 board with 200 mm² copper; requires heatsinking above ~500 mW dissipation |
| Cre | 2.8 pF at VCB = −30 V - limits feedback in high-gain amplifier configurations and affects stability margin |
Pinout & Package
BF423G is housed in a Pb-free TO-92 package (Case 29, Style 14), with leads bent for through-hole mounting. Thermal resistance is RJL = 68°C/W (junction-to-lead) and RJA = 150°C/W (junction-to-ambient) on standard FR4 layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Emitter | Current exit terminal in PNP operation; connects to most positive rail in high-side switch configurations |
| 2 | Collector | Current entry terminal; handles high-voltage load connection (e.g., CRT anode supply or flyback transformer primary) |
| 3 | Base | Control input; requires negative base current to turn on; VBE(sat) ≤ −2.0 V confirms drive compatibility with TTL-compatible logic levels |
Key Features
| Feature | Design Value |
|---|---|
| High VCEO/VCBO | −250 V rating enables direct use in CRT horizontal output and industrial HV power supply switching without cascading |
| Pb-free, RoHS-compliant | Meets global environmental compliance requirements without compromising thermal or electrical performance |
| Wide TJ range | −55°C to +150°C operation supports deployment in automotive under-hood and industrial control environments |
| Low Cre | 2.8 pF reduces Miller effect in high-gain amplifier stages, improving bandwidth and stability margins |
Applications
| CRT Horizontal Deflection | Industrial HV Power Switching |
|---|---|
Use Scenario: Driving flyback transformer primary in analog CRT display scan circuits requiring fast turn-off and high peak voltage tolerance. IC Role / Device Role / Timing Role: High-voltage PNP switch operating in self-oscillating or externally triggered horizontal output stage. Use Value: −250 VCEO withstands retrace voltage spikes; 60 MHz fT supports clean waveform edge fidelity during 15.734 kHz scanning. |
Use Scenario: Controlling relay coils, solenoids, or HV bias rails in programmable logic-controlled industrial equipment. IC Role / Device Role / Timing Role: Medium-current, high-voltage interface switch translating microcontroller outputs to 100–200 V loads. Use Value: VCE(sat) ≤ −0.5 V ensures <100 mW conduction loss at 200 mA; TO-92 allows compact board placement with minimal footprint. |
| Linear HV Amplifier Stage | Legacy Telecom Line Driver |
Use Scenario: Amplifying low-level video or sync signals into high-impedance HV loads (e.g., CRT grid modulation). IC Role / Device Role / Timing Role: Common-emitter linear amplifier biased in Class-A mode for low-distortion signal reproduction. Use Value: hFE ≥50 and low Cre (2.8 pF) maintain gain flatness up to 10 MHz; wide TJ range ensures stability over ambient variations. |
Use Scenario: Driving legacy analog telephone line interfaces requiring ±100 V swing capability and ESD-tolerant termination. IC Role / Device Role / Timing Role: High-voltage output buffer in line card circuitry handling ring signal generation and off-hook detection. Use Value: −250 VCBO accommodates ringing voltage transients; IEBO ≤ −100 nA ensures minimal leakage-induced false detection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage PNP transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BF421G | Higher VCEO/VCBO (−300 V), same package and hFE; otherwise identical electrical specs | Suitable where higher voltage margin is required (e.g., >250 V transient environments) | Select BF421G when design margin demands ≥300 V standoff; BF423G preferred for cost-sensitive 250 V systems |
| MPSA92 | Same VCEO (−300 V), but lower hFE (min 25), higher VCE(sat) (−1.0 V), and different TO-92 pinout (E-B-C vs E-C-B) | Requires PCB layout revision due to pinout mismatch; less suitable for precision gain-critical stages | Use only if pinout redesign is acceptable and gain tolerance >25 is sufficient; not drop-in compatible with BF423G |
Compared with BF421G and MPSA92, the BF423G offers optimal balance of 250 V rating, 50× minimum hFE, −0.5 V saturation, and E-C-B pinout - enabling direct replacement in legacy CRT and industrial HV designs without layout change or gain recalibration.
Availability
BF423G is available at Aetrix Electronics and suitable for CRT display manufacturing, industrial power supply design, and legacy telecom hardware repair requiring stable component supply and long-term obsolescence management.
Supply support for BF423G 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 BF423G belongs to onsemi's high-voltage discrete transistor family, engineered specifically for reliability in CRT deflection, industrial HV switching, and legacy analog signal conditioning applications.
FAQ
What is the maximum collector-emitter voltage rating for BF423G?
The BF423G has a maximum collector-emitter voltage (VCEO) rating of −250 Vdc, verified per onsemi's BF421/D datasheet under IC = −1.0 mAdc and IB = 0 conditions. This rating applies to common-emitter configuration and must not be exceeded to avoid avalanche breakdown. Derating is required above 25°C ambient per the 6.6 mW/°C thermal specification.
Is BF423G pin-compatible with BF421G?
Yes, BF423G is pin-compatible with BF421G - both use identical TO-92 package (Case 29, Style 14) with emitter-base-collector (E-C-B) pinout. The BF423G and BF421G share identical mechanical dimensions, thermal characteristics, and pin assignments; only their voltage ratings differ (−250 V vs −300 V).
What is the DC current gain (hFE) of BF423G under standard test conditions?
The BF423G guarantees a minimum DC current gain (hFE) of 50 when tested at IC = −25 mAdc and VCE = −20 Vdc, as specified in the onsemi BF421/D datasheet. This value is confirmed across the full operating temperature range (−55°C to +150°C), with typical hFE rising to ~100 at 25°C per Figure 1.
Does BF423G meet RoHS and lead-free requirements?
Yes, BF423G is Pb-free, halogen-free/BFR-free, and RoHS compliant per onsemi's official marking and packaging documentation. The "G" suffix in BF423G explicitly denotes the Pb-free TO-92 variant, and the device carries the RoHS-compliant marking per the BF421/D datasheet revision 5 (July 2010).
What is the thermal resistance (RJA) of BF423G on a standard PCB?
The BF423G has a junction-to-ambient thermal resistance (RJA) of 150°C/W when mounted on a standard FR4 board with 200 mm² of 1 oz copper and 5 mm lead length, as documented in the onsemi BF421/D datasheet. This value assumes natural convection cooling and must be adjusted for forced airflow or added copper area.
BF423G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 Long Body
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Transistor Type:
- PNP
- Current - Collector (Ic) (Max):
- 500 mA
- Voltage - Collector Emitter Breakdown (Max):
- 250 V
- Vce Saturation (Max) @ Ib, Ic:
- 500mV @ 2mA, 20mA
- 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:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92 (TO-226)
BF423G FAQ
1.How can I place an order for BF423G through Aetrix?
Please submit a Request for Quotation (RFQ) for BF423G 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 BF423G reliable?
The price and inventory of BF423G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BF423G is usually 5 days.
3.What payment methods are accepted for BF423G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BF423G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BF423G?
BF423G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BF423G 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 BF423G?
For technical support, including BF423G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BF423G requirements.
6.How does Aetrix verify that BF423G is sourced from the original manufacturer or authorized distributors?
All BF423G 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 BF423G meets industry standards.
7.What is the process for return or replacement of BF423G?
All BF423G units undergo pre-shipment inspection (PSI). If there is an issue with BF423G, 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 BF423G part is unused and in its original packaging.
Return procedure for BF423G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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