BB208-03,115 - 10V Varactor Diode SOD-323 | NXP Semiconductors
부품 번호: BB208-03,115 ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $0.15 | $0.15 |
| 10 | $0.13 | $1.30 |
| 100 | $0.11 | $11.00 |
| 500 | $0.09 | $45.00 |
| 1,000 | $0.08 | $80.00 |
BB208-03,115 개요
A varactor diode, also called a varicap or variable capacitance diode, is a semiconductor device that exploits the voltage-dependent depletion-layer capacitance of a reverse-biased PN junction. Within the hierarchy of diodes, it belongs to the family of RF and tuning diodes, used as a voltage-controlled capacitor rather than a rectifier. Its capacitance decreases as reverse bias increases, enabling electronic tuning of LC resonant circuits without any moving parts.
The BB208-03 is fabricated using NXP planar technology, which provides tight capacitance distribution and stable tuning characteristics over life and temperature. Key differentiating parameters include a maximum junction capacitance Cd of 23.2 pF at low reverse bias, an average forward current rating of 20 mA, and a wide operating temperature range of -55°C to +125°C, making it suitable for both consumer and industrial RF environments. The small SOD-323 body measures roughly 1.7 mm x 1.25 mm x 0.95 mm with a 1.3 mm lead pitch, supporting high-density PCB layouts.
Because the device is optimized for low-voltage operation, it pairs naturally with battery-powered and low-supply-voltage tuning circuits where higher-voltage varactors cannot reach their tuning range.
Typical applications include VCO (voltage-controlled oscillator) tuning in RF transceivers, electronically tuned LC filters, antenna impedance matching networks, and frequency modulation circuits in communications equipment.
Design-wise, keep the tuning voltage well within the 10 V reverse rating, use high-value series resistors to isolate the tuning node from oscillator noise, and account for the capacitance-temperature drift of the planar junction in narrow-band designs.
This page synthesizes distributor availability data, verified datasheet parameters, and practical design guidance for the BB208-03,115 not consolidated on the manufacturer product page.
드롭인 대체품: BB208-03,115 — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: BB208-03,115 (동일 폼 팩터 및 풋프린트) — 차이점: Device Type, Operating Temperature Range, Package, Terminal Form.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
이 제품에는 사용 가능한 드롭인 대체품이 없습니다.
대체품 요청BB208-03,115 최대 정격 & 전기적 특성
| Device Type | Variable capacitance diode (varactor) |
| Configuration | Single |
| Repetitive Peak Reverse Voltage (VRRM) | 10 V |
| Junction Capacitance Cd @ 7.5 V, 1 MHz | 5.4 pF |
| Capacitance Ratio (C1/C7.5) | 5.2 |
| Max Junction Capacitance Cd @ Vr, f | 23.2 pF |
| Average Forward Current (IF(AV)) | 20 mA |
| 동작 온도 범위 | -55°C to +125°C |
| Technology | Planar |
| 패키지 | SOD-323 (SC-76) |
| Package Dimensions | 1.7 mm x 1.25 mm x 0.95 mm |
| Lead Pitch | 1.3 mm |
| Number of Terminals | 2 |
| Terminal Form | Gull Wing |
| 실장 유형 | Surface Mount |
| Packing / Ordering Suffix | ,115 (standard packing) |
BB208-03,115 핀 구성
| 핀 1 | Cathode — Cathode terminal - reverse bias is applied here relative to anode; polarity marking per device body marking |
| 핀 2 | Anode — Anode terminal of the varactor junction |
일반적인 애플리케이션
BB208-03,115 적합 용도: 6 애플리케이션s: VCO Tuning in RF Transceivers, Electronically Tuned LC Filters, Antenna Impedance Matching Networks, FM Modulation Circuits, Battery-Powered Tuners and Low-Voltage Radios, Test and Measurement Instrumentation.
VCO Tuning in RF Transceivers
The BB208-03,115 fits VCO tank circuits because its low-voltage C-V characteristic (5.4 pF at 7.5 V, ratio 5.2) allows a full tuning span from control voltages generated by low-voltage DACs or charge pumps. Placed across the inductor in the LC resonator, the diode's capacitance shifts the oscillation frequency as the tuning voltage varies. Because the planar junction has a smooth, repeatable C-V curve, frequency-versus-voltage linearity is predictable, easing calibration. Keep the DC tuning node isolated with a high-value series resistor (tens of kohms) so oscillator phase noise does not modulate the diode, and use bypass capacitors to decouple the tuning line without loading the RF tank.
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Electronically Tuned LC Filters
Variable capacitance diodes like the BB208-03,115 enable voltage-controlled bandpass and low-pass filters where fixed capacitors cannot track changing channel assignments. With 23.2 pF maximum Cd at low bias dropping to about 5.4 pF near 7.5 V, a single diode can swing a filter center frequency over a useful range without relays or switched capacitor banks. The 10 V reverse rating and -55°C to +125°C operating range suit industrial RF front ends. Design consideration: the effective Q of the varactor adds series loss to the tank, so narrow high-Q filters should budget insertion loss and verify the bias network does not shunt RF, typically via RF chokes or large-value resistors.
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Antenna Impedance Matching Networks
In portable and IoT transmitters, antenna impedance shifts with enclosure, hand position, and proximity effects. The BB208-03,115 provides electronically variable shunt capacitance in Pi- and L-match networks, letting a controller retune the match in real time as load conditions change. Its small SOD-323 footprint (1.7 mm x 1.25 mm) allows placement directly at the antenna feed point, and the 20 mA forward current rating and 10 V reverse rating handle typical RF swing levels in sub-watt transmitters. Because varactor capacitance is bias-dependent, a clean, well-bypassed tuning voltage supply directly determines match stability; ripple on this rail appears as unintended frequency or match modulation.
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FM Modulation Circuits
Applying an audio or data modulation signal to the tuning node of a varactor-loaded oscillator produces direct frequency modulation. The BB208-03,115's monotonic, low-hysteresis planar C-V characteristic translates modulation voltage into proportional frequency deviation, which is the core mechanism in FM transmitters, wireless microphones, and telemetry links. With a capacitance ratio of 5.2 across the 0 V to 7.5 V control range, modest modulation voltages yield usable deviation around a stable center frequency. Designers should bias the diode in the mid-range of its C-V curve, where dC/dV is most linear, to minimize modulation distortion, and AC-couple the modulation source into the DC bias point.
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Battery-Powered Tuners and Low-Voltage Radios
The BB208-03 family is explicitly characterized as a low-voltage variable capacitance diode, making it appropriate for single-cell and low-rail consumer radios where classic 20 V to 30 V varactors cannot be biased into their tuning range. At a 5 V or 3.3 V rail the BB208-03,115 still delivers a meaningful capacitance swing (several picofarads), preserving electronic tuning without a boost converter. Quiescent current of the tuning network is essentially zero because the diode is reverse biased, which preserves battery life. The main trade-off is reduced tuning ratio at low bias voltages, so receiver designers should verify channel coverage at the minimum available rail voltage before committing to the design.
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Test and Measurement Instrumentation
In signal generators, sweep oscillators, and alignable IF strips, varactor tuning removes hand-adjusted trimmer capacitors and enables automated, repeatable factory calibration. The BB208-03,115's stable planar construction and -55°C to +125°C rating support instrument-grade frequency accuracy across environmental conditions. A calibration routine can store tuning-voltage-to-frequency tables in memory, compensating for unit-to-unit capacitance spread within the datasheet distribution. Because the diode's capacitance drifts slightly with temperature, precision instruments may pair the varactor with a temperature sensor and lookup-table correction. The SOD-323 package's predictable parasitics (roughly sub-nH lead inductance) simplify simulation of the resonator in RF design tools.
추천
추천 제품 요약
엔지니어링 참조 데이터: BB208-03,115 — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | BB208-02,115 |
|---|---|---|
| Package | SOD-323 (SC-76) | SOD-523 (SC-79) - smaller, NOT pin-compatible |
| Brand | NXP Semiconductors | NXP Semiconductors |
| Reverse Voltage (VRRM) | 10 V | 10 V |
| Operating Temperature | -55°C to +125°C | -55°C to +125°C |
주요 차별점
- Low-voltage optimization (vs Higher-voltage varactor families (e.g., 20-30 V rated tuning diodes))
- Same silicon in two footprints (vs BB208-02,115)
- Wide industrial temperature range (vs Typical consumer-grade tuning diodes)
설계 노트
Isolate the varactor tuning node from RF and noise with a high-value series resistor (typically 10 kohm to 100 kohm) between the control voltage source and the diode cathode. Any noise or ripple on the tuning rail directly frequency-modulates the oscillator, degrading phase noise. Add local RF bypassing (e.g., 10 nF at the bias node) so tuning-voltage transients do not couple into the tank, while ensuring the bypass does not swallow the modulation signal in FM applications.
Estimated: keep the instantaneous reverse voltage across the BB208-03,115 below the 10 V VRRM rating under worst-case conditions, including RF swing superimposed on the DC bias. For example, with 8 V DC bias and a tank that swings +/-1.5 V at the diode, the peak reverse voltage approaches 9.5 V - only 0.5 V margin. Derating the tuning rail to 7 V to 8 V preserves reliability and still covers most of the useful 5.2:1 capacitance ratio.
Do not assume a varactor's nominal capacitance defines the tuning range - always design from the datasheet C-V curve. At very low reverse bias the BB208-03's capacitance approaches its 23.2 pF maximum with high dC/dV, which makes the oscillator very sensitive to bias error and temperature. Bias in the mid-curve region for linearity. Also verify the varactor's effective Q at your operating frequency, since junction losses add insertion loss to high-Q filters.
규정 준수 정보
Compliance status not stated in retrieved web data; the ,115 ordering suffix conventionally indicates RoHS-compliant lead-free packing for NXP parts, but this must be confirmed on the official NXP product page.
