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NXP Semiconductors BF861A,215
- Part No.:
- BF861A,215
- Manufacturer:
- NXP Semiconductors
- Category:
- Single FETs, MOSFETs
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BF861A,215.pdf
- Description:
- RF MOSFET JFET 25V SOT23
- Quantity:
- Payment:
- Shipping:
Inventory:8,686
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Product details
Overview
BF861A,215 from NXP Semiconductors is an N-channel symmetrical junction field-effect transistor (JFET) in SOT23 package, designed for low-noise RF and audio preamplifier stages. It delivers 2–6.5 mA drain current (IDSS), 12–20 mS forward transfer admittance (|yfs|), and ultra-low 10 pF input capacitance (Ciss), enabling high-gain, wideband amplification in AM tuner front-ends.
For engineers reviewing the BF861A,215 datasheet, BF861A,215 pinout, BF861A,215 application, or BF861A,215 equivalent, this device is selected for low-noise analog signal conditioning where gate-source cutoff voltage (VGSoff = −0.2 to −1 V), thermal resistance (Rth(j-a) = 500 K/W), and static-sensitive handling are critical design considerations.
Technical Context
The BF861A,215 operates as a depletion-mode N-channel JFET with symmetrical source/drain terminals, requiring zero-bias gate control for linear amplification. Its junction-based structure provides inherent low 1/f noise and stable DC characteristics over temperature.
Designed for small-signal amplification, it features low feedback capacitance (Crss ≤ 2.7 pF) and high input impedance (>10⁹ Ω), supporting broadband operation up to VHF without neutralization. Gate-source breakdown voltage (V(BR)GSS = −25 V) and gate cut-off current (IGSS ≤ −1 nA) ensure robustness in low-power analog circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IDSS | 2–6.5 mA at VGS = 0 V, VDS = 8 V: sets DC bias point and gain linearity in common-source amplifier configurations. |
| |yfs| | 12–20 mS at VGS = 0 V, VDS = 8 V: defines small-signal transconductance and achievable voltage gain per stage. |
| Ciss | ≤10 pF at f = 1 MHz: minimizes Miller effect and preserves bandwidth in tuned RF preamplifiers. |
| Crss | ≤2.7 pF at f = 1 MHz: reduces unwanted feedback and improves stability in high-gain amplifier designs. |
| VGSoff | −0.2 to −1 V at ID = 1 μA: determines gate biasing requirements and operating point selection in self-biased circuits. |
| Vn/√B | Typ. 1.5 nV/√Hz at f = 1 MHz: enables high signal-to-noise ratio in AM radio front-end applications. |
| Ptot | 250 mW at Tamb = 25 °C: defines maximum dissipation before thermal derating; requires PCB copper area for heat spreading. |
Pinout & Package
SOT23 plastic surface-mounted package (3 leads); compact 2.9 × 1.3 × 1.0 mm footprint optimized for space-constrained RF modules and automotive tuner assemblies.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Source | Reference node for gate bias; symmetrical with drain-enables bidirectional use in certain AC-coupled topologies. |
| 2 | Drain | Output terminal for common-source amplification; connects to load resistor or RF choke for DC biasing. |
| 3 | Gate | High-impedance control terminal; must be protected against ESD during handling and PCB assembly. |
Key Features
| Feature | Design Value |
|---|---|
| Low input capacitance | Ciss ≤ 10 pF ensures minimal loading on preceding tuned circuits and preserves Q-factor in AM IF stages. |
| Low noise performance | 1.5 nV/√Hz input-referred noise enables high-fidelity reception in weak-signal automotive AM tuners. |
| High transfer admittance | |yfs| = 12–20 mS supports >20 dB voltage gain per stage without external neutralization. |
| Symmetrical junction structure | Source/drain interchangeability simplifies layout and allows flexible biasing in discrete amplifier designs. |
| ESD-protected packaging | Antistatic SOT23 tape-and-reel prevents gate oxide damage during automated placement and reflow. |
Applications
| AM Radio Tuner Preamplifier | Low-Noise Audio Input Stage |
|---|---|
Use Scenario: Front-end amplification of antenna signals in automotive AM radio receivers before mixer stage. IC Role / Device Role / Timing Role: N-channel JFET configured as common-source amplifier providing first-stage gain and noise figure optimization. Use Value: 1.5 nV/√Hz noise floor and 12–20 mS transconductance enable reliable reception of weak AM stations below 10 μV/m field strength. |
Use Scenario: High-impedance microphone or phono cartridge preamplifier in portable audio equipment. IC Role / Device Role / Timing Role: Discrete JFET used in DC-coupled or capacitor-input gain stage for analog audio signal conditioning. Use Value: Ultra-low Crss (≤2.7 pF) and high input impedance (>10⁹ Ω) preserve signal integrity and minimize high-frequency roll-off. |
| RF Signal Buffer | Wideband Oscillator Active Device |
Use Scenario: Impedance-matching buffer between crystal filter and mixer in superheterodyne receiver architectures. IC Role / Device Role / Timing Role: Source-follower configuration providing low-output-impedance drive while isolating sensitive filter networks. Use Value: Symmetrical source/drain terminals and low Ciss allow stable unity-gain buffering up to 30 MHz without peaking. |
Use Scenario: Active element in Colpitts or Clapp oscillator circuits for local oscillator generation in AM/FM tuners. IC Role / Device Role / Timing Role: Depletion-mode JFET sustaining oscillation via controlled negative resistance in resonant tank network. Use Value: Predictable VGSoff and low Crss support stable frequency start-up and low phase noise in <100 MHz LO designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise JFET amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 2SK208-4-TB-E | Higher IDSS (5–12 mA), higher |yfs| (15–30 mS), TO-92 package; 200 mW Ptot. | Requires through-hole mounting; better suited for prototyping or non-automated production. | Select when board-level rework tolerance or manual assembly is prioritized over SMT density. |
| J310 | Lower IDSS (24–60 mA), higher VGSoff (−0.5 to −3.5 V), TO-92; no specified Crss or Ciss values in standard datasheet. | Less predictable RF performance due to missing high-frequency capacitance specs; wider VGSoff spread increases biasing complexity. | Choose only for general-purpose DC/low-frequency amplification where RF stability and noise are not critical. |
Compared with BF861A,215, the 2SK208-4-TB-E offers higher gain but sacrifices SMT compatibility, while the J310 trades off RF specification rigor for broader availability-making BF861A,215 the preferred choice for production-grade AM tuner front-ends demanding repeatable noise and capacitance behavior.
Availability
BF861A,215 is available at Aetrix Electronics and suitable for automotive AM radio tuners, low-noise audio preamplifiers, and RF signal buffering applications requiring stable component supply across extended production lifecycles.
Supply support for BF861A,215 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 secure connectivity solutions for automotive, industrial, and consumer electronics.
The BF861A,215 belongs to NXP's legacy RF discrete portfolio, developed specifically for high-fidelity analog signal conditioning in broadcast receiver systems where low-noise, low-capacitance, and SMT manufacturability are essential.
FAQ
What is the maximum drain-source voltage rating for BF861A,215?
The BF861A,215 has a maximum drain-source voltage (VDS) rating of 25 V under DC conditions. This absolute maximum rating must not be exceeded to prevent permanent device damage. Operation above 25 V violates IEC 60134 limiting values and risks junction breakdown. The BF861A,215 is intended for low-voltage analog signal paths, not power switching applications.
How does the gate-source cutoff voltage (VGSoff) affect biasing of BF861A,215?
The BF861A,215 exhibits a VGSoff range of −0.2 V to −1 V at ID = 1 μA, defining the gate voltage required to pinch off the channel. This narrow cutoff window enables precise self-biasing using source degeneration resistors, ensuring stable quiescent current in common-source amplifiers. The BF861A,215's tight VGSoff distribution simplifies production calibration compared to wider-spread alternatives like J310.
Is BF861A,215 suitable for automotive applications?
The BF861A,215 is not automotive-qualified per NXP's documentation. While widely used in car radio tuners, it lacks AEC-Q101 stress testing and automotive-grade reliability validation. For safety-critical or long-lifecycle automotive deployments, users must perform independent qualification. The BF861A,215 remains appropriate for cost-sensitive consumer-grade automotive infotainment systems where full qualification is not mandated.
What is the thermal resistance from junction to ambient for BF861A,215?
The BF861A,215 has a typical thermal resistance from junction to ambient (Rth(j-a)) of 500 K/W when mounted on a standard FR4 PCB. This value assumes minimal copper pour; adding thermal vias and 1 cm² of 2-oz copper on the source pad can reduce Rth(j-a) by ~30%. Exceeding 250 mW total power dissipation at Tamb = 25 °C will cause junction temperatures to exceed the 150 °C maximum rating unless active cooling or derating is applied.
Why does BF861A,215 require ESD protection during handling?
The BF861A,215 uses a junction-gate structure with thin gate oxide susceptible to electrostatic discharge. Gate-source breakdown voltage is rated at −25 V, but human-body-model ESD events exceeding 100 V can permanently degrade performance. The antistatic SOT23 packaging and explicit handling cautions in the datasheet reflect this vulnerability. Proper grounding, ionized air, and ESD-safe workstations are mandatory when soldering or probing the BF861A,215.
BF861A,215 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Technology:
- JFET
- Configuration:
- N-Channel
- Frequency:
- -
- Gain:
- -
- Voltage - Test:
- -
- Current Rating (Amps):
- 6.5mA
- Noise Figure:
- -
- Current - Test:
- -
- Power - Output:
- -
- Voltage - Rated:
- 25 V
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23 (TO-236AB)
BF861A,215 FAQ
1.How can I place an order for BF861A,215 through Aetrix?
Please submit a Request for Quotation (RFQ) for BF861A,215 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 BF861A,215 reliable?
The price and inventory of BF861A,215 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BF861A,215 is usually 5 days.
3.What payment methods are accepted for BF861A,215?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BF861A,215 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BF861A,215?
BF861A,215 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BF861A,215 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 BF861A,215?
For technical support, including BF861A,215 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BF861A,215 requirements.
6.How does Aetrix verify that BF861A,215 is sourced from the original manufacturer or authorized distributors?
All BF861A,215 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 BF861A,215 meets industry standards.
7.What is the process for return or replacement of BF861A,215?
All BF861A,215 units undergo pre-shipment inspection (PSI). If there is an issue with BF861A,215, 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 BF861A,215 part is unused and in its original packaging.
Return procedure for BF861A,215:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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