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Nexperia USA Inc. BF621-QX
- Part No.:
- BF621-QX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Bipolar Transistors
- Package:
- TO-243AA
- Datasheet:
-
BF621-QX.pdf
- Description:
- TRANS PNP 300V 0.05A SOT-89
- Quantity:
- Payment:
- Shipping:
Inventory:1,000
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Product details
Overview
BF621-QX from Nexperia is a PNP high-voltage bipolar junction transistor in SOT89 (SC-62) surface-mount package, rated for -300 V VCEO, -50 mA IC, and DC current gain (hFE) ≥50 at -25 mA and -20 V. It operates up to 150 °C junction temperature and is AEC-Q101 qualified for automotive video output stages.
For engineers reviewing the BF621-QX datasheet, BF621-QX pinout, BF621-QX application, or BF621-QX equivalent, key selection criteria include high-voltage PNP switching capability, thermal performance on FR4 PCBs with varying collector pad sizes, and automotive-grade reliability validation per AEC-Q101.
Technical Context
This device functions as a high-voltage, low-current PNP switch with open-base VCEO = -300 V and peak collector current ICM = -100 mA. Its hFE of 50 at -25 mA ensures predictable base drive requirements in linear or saturated switching modes.
Thermal design must account for Rth(j-a) ranging from 113 K/W (6 cm² collector pad) to 250 K/W (standard footprint), and transient thermal impedance varies significantly with pulse duration and duty cycle per Figures 2–4.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | -300 V - Maximum safe collector-emitter voltage with base open; defines high-side switching headroom in video flyback or CRT driver circuits. |
| IC | -50 mA - Continuous DC collector current rating; sets upper bound for sustained analog or switching load current. |
| hFE | ≥50 - Minimum DC current gain at VCE = -20 V, IC = -25 mA; determines required base drive current for saturation. |
| VCE(sat) | ≤ -800 mV - Collector-emitter saturation voltage at IC = -30 mA, IB = -5 mA; impacts conduction loss and thermal load in on-state. |
| Ptot | 1.1 W - Total power dissipation with 6 cm² collector pad on FR4; defines maximum steady-state power handling under optimized layout. |
| fT | 60 MHz - Transition frequency at VCE = -10 V, IC = -10 mA; indicates usable bandwidth for video-frequency amplification or fast switching. |
| Rth(j-sp) | 30 K/W - Junction-to-solder-point thermal resistance; critical for estimating local temperature rise at solder joint during pulsed operation. |
Pinout & Package
The BF621-QX uses the SOT89 (SC-62) plastic surface-mount package: 3 leads, 1.5 mm pitch, 4.5 mm × 2.5 mm × 1.5 mm body, with exposed collector tab for thermal conduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | E (Emitter) | Current source terminal for PNP operation; connects to higher potential rail in high-side switch configurations. |
| 2 | C (Collector) | Main current sink terminal; electrically and thermally connected to exposed metal tab for PCB heat spreading. |
| 3 | B (Base) | Control input for forward-biased PNP operation; requires negative bias relative to emitter to turn on. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use per Stress Test Qualification for Discrete Semiconductors - enables deployment in infotainment video outputs without additional qualification effort. |
| High VCEO (-300 V) | Supports operation in CRT deflection, video output, and flyback transformer driver circuits where high reverse voltage blocking is essential. |
| Thermally optimized SOT89 package | Exposed collector tab and defined mounting pad areas (1 cm² or 6 cm²) enable predictable thermal resistance from junction to ambient (113–250 K/W). |
| Low leakage (ICBO ≤ -10 nA @ 25 °C) | Ensures stable off-state behavior in high-impedance video coupling paths and minimizes standby power loss. |
Applications
| Video Output Stages | Automotive Display Drivers |
|---|---|
Use Scenario: Driving cathode loads in analog RGB video output circuits for legacy displays or rear-seat entertainment systems. IC Role / Device Role / Timing Role: PNP current sink amplifier stage operating in linear or Class-A mode, handling composite sync and blanking signals. Use Value: -300 V VCEO withstands flyback transients; -800 mV VCE(sat) minimizes signal distortion at full swing. | Use Scenario: CRT-based instrument cluster or head-up display video driver in passenger vehicles meeting AEC-Q101 requirements. IC Role / Device Role / Timing Role: High-voltage PNP switch controlling electron beam intensity or deflection coil current in analog display subsystems. Use Value: AEC-Q101 qualification confirms reliability across -40 °C to +125 °C ambient; 150 °C Tj supports under-hood proximity mounting. |
| Flyback Converter Snubber Switches | Industrial Video Signal Amplifiers |
Use Scenario: Clamping diode replacement or active snubber switch in low-power flyback converters powering analog video supplies. IC Role / Device Role / Timing Role: Fast-turn-off PNP clamp transistor absorbing inductive kickback energy during MOSFET off-time. Use Value: 60 MHz fT enables sub-microsecond switching; -100 mA ICM handles short-duration surge currents. | Use Scenario: DC-coupled video line driver in broadcast equipment requiring stable gain and low thermal drift. IC Role / Device Role / Timing Role: Linear PNP emitter-follower buffer stage isolating source impedance while preserving signal integrity. Use Value: hFE ≥50 ensures consistent current sourcing; -10 nA ICBO prevents baseline shift over temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP high-voltage transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC807-40 | VCEO = -45 V, IC = -500 mA, hFE = 250–630 - lower voltage rating, higher current, higher gain. | Suitable for general-purpose low-voltage switching but cannot replace BF621-QX in >100 V circuits. | Select only when system voltage remains below 45 V and higher gain/low base drive is prioritized. |
| PN2907A | VCEO = -60 V, IC = -600 mA, TO-92 package - lower voltage, higher current, through-hole mounting. | Applicable in prototyping or low-volume industrial video boards where SMT is not required and voltage stays <60 V. | Choose for manual assembly or legacy board compatibility; not suitable for automotive or high-voltage designs. |
Compared with BC807-40 and PN2907A, the BF621-QX uniquely delivers -300 V blocking capability in an SMT package with AEC-Q101 certification - making it irreplaceable in automotive video flyback and CRT driver applications where voltage, reliability, and form factor are jointly constrained.
Availability
BF621-QX is available at Aetrix Electronics and suitable for automotive display drivers, video output stages, flyback snubber circuits, and industrial analog video amplifiers requiring stable component supply and long-term production continuity.
Supply support for BF621-QX 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
Nexperia is a global semiconductor expert focused on high-volume, high-reliability discrete and logic devices, with leadership in automotive-qualified components and advanced packaging technologies.
The BF621-QX belongs to Nexperia's AEC-Q101-qualified high-voltage bipolar transistor product line, engineered specifically for robust analog video signal handling and flyback circuit protection in automotive and industrial environments.
FAQ
What is the maximum allowable junction temperature for BF621-QX?
The absolute maximum junction temperature (Tj) is 150 °C, as specified in Table 5 (Limiting values). Operation beyond this limit risks permanent degradation of hFE, leakage current, and bond wire integrity. Thermal design must ensure Tj remains within this bound using appropriate PCB copper area and ambient derating per Figure 1.
Is BF621-QX pin-compatible with other SOT89 PNP transistors?
No - pin compatibility cannot be assumed. While BF621-QX follows standard SOT89 pinning (1=E, 2=C, 3=B), other SOT89 PNP devices may assign pins differently (e.g., 1=B, 2=C, 3=E). Always verify pinout from the specific manufacturer's datasheet before PCB layout or replacement.
Does BF621-QX support pulsed operation above its continuous IC rating?
Yes - the peak collector current (ICM) is rated at -100 mA for single pulses ≤1 ms, as stated in Table 5. This allows brief overload handling in flyback snubbing or video sync pulse applications, provided average power and junction temperature remain within limits defined by transient thermal impedance curves (Figures 2–4).
What marking code identifies BF621-QX on the device body?
The BF621-QX is marked with "DF" on the top surface, per Table 4 (Marking codes). This two-character code is laser-etched or molded into the package and serves as the primary visual identifier for traceability and counterfeit detection during incoming inspection.
BF621-QX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- -
- Package/Case:
- TO-243AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Transistor Type:
- PNP
- Current - Collector (Ic) (Max):
- 50 mA
- Voltage - Collector Emitter Breakdown (Max):
- 300 V
- Vce Saturation (Max) @ Ib, Ic:
- 800mV @ 5mA, 30mA
- Current - Collector Cutoff (Max):
- 10nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 50 @ 25mA, 20V
- Power - Max:
- 500 mW
- Frequency - Transition:
- 60MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89
BF621-QX FAQ
1.How can I place an order for BF621-QX through Aetrix?
Please submit a Request for Quotation (RFQ) for BF621-QX 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 BF621-QX reliable?
The price and inventory of BF621-QX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BF621-QX is usually 5 days.
3.What payment methods are accepted for BF621-QX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BF621-QX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BF621-QX?
BF621-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BF621-QX 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 BF621-QX?
For technical support, including BF621-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BF621-QX requirements.
6.How does Aetrix verify that BF621-QX is sourced from the original manufacturer or authorized distributors?
All BF621-QX 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 BF621-QX meets industry standards.
7.What is the process for return or replacement of BF621-QX?
All BF621-QX units undergo pre-shipment inspection (PSI). If there is an issue with BF621-QX, 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 BF621-QX part is unused and in its original packaging.
Return procedure for BF621-QX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BF621-QX Tags
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