BB208-02,115 - Varactor Diode 10V SOD-523 | NXP Semiconductors
MPN: BB208-02,115 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.65 | $0.65 |
| 10 | $0.4 | $4.00 |
| 100 | $0.25 | $25.00 |
| 500 | $0.19 | $95.00 |
| 1,000 | $0.1637 | $163.70 |
BB208-02,115 Overview
A varactor diode, also called a variable capacitance diode or varicap, is a PN-junction diode operated in reverse bias so that its junction capacitance varies predictably with the applied voltage. Within the discrete semiconductor hierarchy, it belongs to the diode family and serves as the tuning element inside voltage-controlled oscillators (VCOs), RF filters, and antenna matching networks, forming part of the broader radio-frequency component chain.
Key features of the BB208-02,115 include its low-voltage 10 V rating suited to battery-powered and portable RF designs, surface-mount SOD-523 packaging that minimizes board area and parasitic inductance, an operating temperature range of -55C to +125C (TJ) for industrial environments, and lead-free RoHS-compliant construction indicated by the ,115 ordering suffix.
The device uses a silicon junction optimized for a well-defined capacitance-versus-voltage (C-V) characteristic, allowing designers to predict tuning range across the control voltage sweep. Because the part is a two-terminal passive-type semiconductor, PCB layout directly determines its effective Q factor: short, wide traces and minimal series inductance preserve tuning resolution at VHF and UHF frequencies.
Typical applications include VCO tuning in wireless transmitters, electronically tuned RF filters, frequency modulation of low-power oscillators, and antenna tuners in consumer and industrial radios.
Design consideration: always verify the junction capacitance and capacitance ratio figures against the manufacturer datasheet before committing a layout, since the BB208 family includes multiple capacitance-range suffixes.
This page synthesizes distributor pricing from LCSC, DigiKey and Mouser, NXP product-page availability data, and drop-in alternative analysis in a single reference not found on any individual distributor page.
Drop-in alternatives for BB208-02,115 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with BB208-02,115 (same form factor and footprint) — differing in Device Type, Operating Temperature Range, Package, Terminal Form.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
BB208-03,115
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.08 / Unit
View Datasheet →BB208-02,215
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
BB208-02,115 Maximum Ratings & Electrical Characteristics
| Device Type | Varactor Diode (Varicap), Single |
| Maximum Reverse Voltage (Vr) | 10 V |
| Diode Configuration | Single, 2-terminal |
| Package | SOD-523 (SC-79) |
| Mounting Type | Surface Mount |
| Number of Terminals | 2 |
| Terminal Form | Flat (DUAL position) |
| Operating Temperature Range | -55C to +125C (TJ) |
| Family | BB208 |
| ECCN | EAR99 |
| Packaging | Reel (TR), 7-inch Q1/T1 |
| Minimum Package Quantity | 3000 |
BB208-02,115 Pin Configuration
| Pin 1 | Cathode — Cathode terminal; connect to tuning voltage side (device operated reverse-biased) |
| Pin 2 | Anode — Anode terminal; connect to RF tank side |
Typical Applications
BB208-02,115 is suitable for 6 applications: VCO Tuning in Wireless Transmitters, Electronically Tuned RF Filters, Antenna Matching Networks, Frequency Modulation of Low-Power Oscillators, Portable Consumer Radio Tuners, Industrial Remote Control and Telemetry Links.
VCO Tuning in Wireless Transmitters
The BB208-02,115 functions as the voltage-controlled tuning element in the LC resonant tank of a VCO, where its junction capacitance varies with the PLL charge-pump tuning voltage. Its 10 V rating matches low-voltage tuning rails common in portable transmitters, and the SOD-523 package keeps parasitic series inductance low, preserving tuning resolution at VHF and UHF. Place the varactor directly across the tank inductor with a high-impedance bias resistor (typically 10k to 100k ohm) and a DC-blocking capacitor. The trade-off versus a varactor with a wider capacitance ratio is reduced tuning bandwidth, so confirm the C-V curve spans your intended channel range before layout freeze.
Recommended
Electronically Tuned RF Filters
In tunable bandpass and notch filters, the BB208-02,115 replaces switched capacitor banks, allowing continuous center-frequency adjustment under MCU or DAC control. Its single-junction configuration with 2 terminals simplifies filter topologies, and the -55C to +125C operating range keeps the passband stable across industrial temperature extremes because junction capacitance drift with temperature is specified by the manufacturer. Use back-to-back pairs for circuits handling symmetric RF swings to reduce distortion. Performance consideration: the filter's loaded Q is limited by the varactor's series resistance, so keep trace lengths short and verify Q from the datasheet at your bias point rather than assuming ideal capacitor behavior.
Recommended
Antenna Matching Networks
The BB208-02,115 can serve as a tunable capacitance in antenna impedance-matching networks for multi-band consumer and industrial radios, where board space constraints make SOD-523 attractive. Because the 10 V maximum reverse voltage bounds the tuning voltage swing, it suits battery-operated products rather than high-power transmitters; keep forward RF swing below the conduction threshold by biasing at several volts of reverse DC. A control DAC sweeps the bias to retune the match as frequency or environment changes, improving radiation efficiency across bands. Trade-off: junction capacitance tolerance affects match accuracy, so include a calibration step in production firmware to compensate unit-to-unit C-V spread.
Recommended
Frequency Modulation of Low-Power Oscillators
An audio or data modulation signal applied to the BB208-02,115 bias node directly frequency-modulates an LC oscillator, a classic analog FM technique used in low-power transmitters, telemetry links, and keyless-entry products. The varactor's capacitance change per volt defines the modulation sensitivity (deviation per volt), and the low-voltage 10 V rating allows modulation circuitry to run from the same supply as the oscillator. Coupling the modulating signal through a large resistor preserves the DC bias while presenting high AC impedance. Keep modulation amplitude small relative to bias voltage to minimize nonlinearity and harmonic distortion of the FM deviation.
Recommended
Portable Consumer Radio Tuners
Battery-powered FM/DAB receivers use varactors like the BB208-02,115 for electronic station tuning, replacing air-variable capacitors with a tiny SOD-523 device controlled by a tuning voltage from the receiver IC or synthesizer. The low tuning voltage requirement matches single-cell or USB-powered designs, and the compact SC-79 outline fits dense portable layouts. Temperature stability from -55C to +125C ensures the tuned frequency stays locked over outdoor use. Performance consideration: the tuner's local oscillator phase noise and drift depend on the varactor Q and bias-network leakage, so use low-leakage bias resistors and follow the manufacturer datasheet biasing recommendations for best drift figures.
Recommended
Industrial Remote Control and Telemetry Links
Industrial short-range radio links in the 315/433/868/915 MHz ISM bands employ the BB208-02,115 to trim or tune the transmitter oscillator against crystal or SAW references, absorbing layout and component tolerances that would otherwise push the carrier out of regulatory limits. The EAR99 export classification simplifies global sourcing, and the wide -55C to +125C range survives factory-floor and outdoor node environments. A production trim routine adjusts the varactor bias once at test, locking the carrier on frequency. Because only a small static bias is needed after trim, long-term reliability of the two-terminal junction is excellent in sealed enclosures.
Recommended
Recommended Products Summary
Engineering reference data for BB208-02,115 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BB208-03,115 | BB208-02,215 |
|---|---|---|---|
| Package | SOD-523 (SC-79) | SOD-523 (SC-79) - same | SOD-523 (SC-79) - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Configuration | Single varactor, 2-terminal | Single varactor, 2-terminal | Single varactor, 2-terminal |
| Max Reverse Voltage | 10 V | 10 V | 10 V |
| Operating Temperature | -55C to +125C | -55C to +125C | -55C to +125C |
| ECCN | EAR99 | EAR99 | EAR99 |
| Packaging | Tape & Reel, 7-inch, min 3000 pcs | Tape & Reel (same family packing) | Alternate packing suffix, same die |
Key Differentiators
- Low 10 V tuning voltage rating (vs BB208-03,115)
- Minimal board footprint (vs Larger SOD-323/SOD-123 varactors)
- Industrial temperature range (vs Consumer-grade varactors)
Design Notes
Minimize series inductance at the two SOD-523 terminals: place the varactor directly across the tank inductor with traces under 3 mm where possible. Series inductance in the cathode leg shifts the effective tuning capacitance downward at UHF and reduces tuning linearity. Use a solid ground plane under the bias network but keep the RF node area clear. The SOD-523 footprint per NXP package drawing should be used verbatim to ensure reliable reflow soldering of the flat 2-terminal lead frame.
A varactor must never be forward-biased in operation: excessive RF swing or a misplaced bias polarity will forward-bias the junction, causing distortion, tuning loss, and possible degradation of the C-V characteristic. Bias the cathode positive relative to the anode by several volts of DC, and verify that peak RF voltage plus tuning voltage stays below the 10 V reverse rating. Confirm the capacitance suffix (-02 vs -03) on incoming reels; the two suffixes fit the same footprint but tune different ranges, a frequent substitution error in production.
The tuning-voltage node must be high-impedance at RF: use a series bias resistor of 10k to 100k ohm and add a bypass capacitor (10 nF to 100 nF) from the bias node to ground, placed close to the varactor cathode. Low-value or missing bias resistance loads the tank, lowering loaded Q and degrading oscillator phase noise. Keep the bias resistor's parasitic capacitance low; thin-film or standard thick-film 0402/0603 resistors are generally adequate up to the upper VHF range for which this low-voltage varactor is intended.
Compliance Information
RoHS/lead-free indicated by NXP ,115 ordering suffix and distributor listings. Reach, halogen-free, and conflict-minerals declarations not present in provided data - request certificate of conformity from NXP.
