BB202,135 - 6V Low-Voltage Varactor Diode SOD-523 | NXP
MPN: BB202,135 β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.23 | $0.23 |
| 10 | $0.21 | $2.10 |
| 100 | $0.17 | $17.00 |
| 500 | $0.14 | $70.00 |
| 1,000 | $0.12 | $120.00 |
BB202,135 Overview
A varactor diode, also called a variable capacitance diode or varicap, is a semiconductor device that exploits the voltage-dependent depletion-layer capacitance of a reverse-biased PN junction. Within the broader diode family, varactors function as voltage-controlled capacitors, and are key passive-to-active tuning elements in RF front ends, voltage-controlled oscillators (VCOs), and tunable LC filter circuits in modern radio and communication systems.
The BB202,135 is fabricated in planar technology, which gives it very consistent capacitance-versus-voltage characteristics and a very low series inductance and resistance, important for high-Q resonant tank circuits. Its headline differentiator is its low-voltage operation: the tuning characteristic is fully exploited within a 0.2 V to 2.3 V control range, making it a natural match for battery-powered portable equipment and low-voltage PLL loops where tuning voltage rails of only 3 V or less are available.
The capacitance ratio of 2.5 (C0.2/C2.3) means the junction capacitance drops from roughly 28 pF at 0.2 V to 11.2 pF at 2.3 V, providing a useful tuning span for LC tanks in the VHF range. The SOD-523 package minimizes parasitic inductance, supporting use well into the hundreds of MHz.
Typical applications include VHF tuner circuits, portable radio receivers, voltage-controlled oscillators in wireless transceivers, and low-voltage electronic tuning in consumer communication products.
When designing with this device, keep the tuning voltage well filtered to avoid phase noise degradation, and account for the 6 V peak reverse voltage limit when sizing bias networks.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for BB202,135 β 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 BB202,135 (same form factor and footprint) β differing in Capacitance Ratio, Device Type.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
BB202,115
β Drop-Inβ In Stock
$0.038 / Unit
View Datasheet βBB202T
β Drop-Inπ Reference alternative (not in catalog)
BBY5302WH6327XT
β Drop-Inπ Reference alternative (not in catalog)
BB202,135 Maximum Ratings & Electrical Characteristics
| Device Type | Variable capacitance diode (varactor) |
| Maximum Peak Reverse Voltage | 6 V |
| Capacitance at Vr | 11.2 pF @ 2.3 V, 1 MHz |
| Capacitance Ratio | 2.5 (C0.2/C2.3) |
| Continuous Forward Current | 10 mA |
| Technology | Planar |
| Package / Case | SC-79, SOD-523 |
| Mounting Type | Surface Mount |
| Configuration | Single |
| Series | Low-voltage variable capacitance diode |
| Packaging | Tape & Reel (TR), Cut Tape (CT), Digi-Reel |
| ECCN | EAR99 |
| Country of Origin | China |
| Introduction Date | February 18, 2002 |
BB202,135 Pin Configuration
| Pin 1 | Cathode β Cathode terminal; connect to tuning voltage / high-potential side of tank |
| Pin 2 | Anode β Anode terminal; connect to RF tank / low-potential side |
Typical Applications
BB202,135 is suitable for 6 applications: VHF Tuner Circuits, Voltage-Controlled Oscillators (VCO), Portable Battery-Powered Radio Receivers, Tunable LC Filters, RF Parametric Amplification and Frequency Multiplication, Legacy Product Maintenance and Repair.
VHF Tuner Circuits
The BB202,135 was designed explicitly as a tuner diode for VHF radio receivers, and its low-voltage tuning span of roughly 28 pF at 0.2 V to 11.2 pF at 2.3 V maps directly onto 3 V-controlled varicap front ends. In a typical application, the diode is placed across the antenna or RF tank inductor, and the control voltage from the tuning potentiometer or PLL charge pump sweeps the resonant frequency across the band. Its planar construction keeps series resistance low, preserving tank Q. Since the part is NRND, use it for servicing legacy tuners and qualify a current varicap for new tuner designs.
Recommended
Voltage-Controlled Oscillators (VCO)
In a VCO tank, the BB202,135 acts as the voltage-tunable element whose depletion capacitance sets the oscillation frequency. The 2.5 capacitance ratio (C0.2/C2.3) provides a wide tuning span from a control voltage below 3 V, ideal for battery-powered PLL loops where the charge pump output is only 2.5 V to 3 V. The diode couples to the tank via a DC-blocking capacitor and a high-value bias resistor to isolate RF from the control node. The very low series inductance of the SOD-523 package minimizes parasitic frequency offset at VHF. Filter the tuning line heavily to prevent control-voltage ripple from converting into phase noise.
Recommended
Portable Battery-Powered Radio Receivers
The defining trait of the BB202,135 for portable radio receivers is that full tuning authority is reached at only 2.3 V reverse bias, so a single 3 V battery rail can drive the tuning network without a voltage multiplier. Receivers using electronic tuning can sweep the full 2.5:1 capacitance range with a simple resistor divider from the battery, keeping cost and quiescent current minimal. The 10 mA forward-current rating and 6 V reverse limit give generous margins for this class of product. The SOD-523 package occupies under 1 mmΒ² of board area, allowing dense tuner modules in pocket radios and headsets.
Recommended
Tunable LC Filters
Varactor-tuned LC bandpass and notch filters use the BB202,135 to electronically shift the passband without mechanical trimming. Placing the diode in the filter tank and sweeping its bias from 0.2 V to 2.3 V shifts the resonant frequency in proportion to the square root of the capacitance change, covering roughly a 1.6:1 frequency span given the 2.5 capacitance ratio. The low series resistance of the planar die keeps filter insertion loss acceptable at VHF. Designers should series the varicap with a DC block and keep RF swing across the diode well below the bias voltage to avoid distortion from capacitance modulation.
Recommended
RF Parametric Amplification and Frequency Multiplication
Varactors exploit their nonlinear, voltage-dependent capacitance to mix, multiply, or parametrically amplify RF signals, and the BB202,135 serves this role at low drive levels in VHF circuits. Its planar junction provides a predictable C-V curve, allowing designers to compute conversion efficiency from the 2.5 capacitance ratio. In a frequency multiplier, the diode is driven by a pump signal superimposed on DC bias; harmonics are generated by capacitance modulation and extracted through a tuned output network. Keep instantaneous reverse voltage below the 6 V limit at all times, and note the NRND status when planning new multiplier designs.
Recommended
Legacy Product Maintenance and Repair
Because the BB202,135 has been in circulation since its introduction on February 18, 2002 and is now NRND, one of its most common current uses is repairing and sustaining legacy VHF tuners, two-way radios, and consumer communication equipment designed around its exact 11.2 pF / 2.5-ratio characteristic. Direct drop-in substitutes BB202,115 and BB202T keep repairs footprint-compatible, while Infineon BBY5302WH6327XT offers a cross-brand fallback listed in the official cross-reference. Buyers should secure existing distributor stock (LCSC lists it in stock from about $0.23 as of 2026-09-13) before it becomes fully obsolete.
Recommended
Recommended Products Summary
Engineering reference data for BB202,135 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BB202,115 | BB202T | BBY5302WH6327XT |
|---|---|---|---|---|
| Package | SOD-523 (SC-79) | SOD-523 (SC-79) - same | SOD-523 (SC-79) - same | SOD-523 (SC-79) - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | Infineon |
| Lifecycle Status | NRND (not recommended for new designs) | Same die/ordering variant | Same die/ordering variant | Active current production (preferred for new designs) |
Key Differentiators
- Ultra-low-voltage tuning range (vs BBY5302WH6327XT)
- Very low series inductance from SOD-523 package (vs BB202,115)
- Honest trade-off: lifecycle risk (vs BBY5302WH6327XT)
Design Notes
Reverse-bias discipline is essential for reliable varicap operation. Keep the instantaneous reverse voltage across the BB202,135 strictly below the 6 V maximum rating under all RF and bias conditions: for a large RF swing in the tank, the peak total voltage (DC bias plus RF amplitude) can exceed the DC bias value alone. Also size the bias resistor (typically 10k to 100k) so leakage currents do not shift the operating point. Exceeding the rating forward-biases or avalanches the junction, degrading Q and shifting the C-V curve permanently.
Filter the tuning-voltage node aggressively. Any ripple, PLL reference feedthrough, or supply noise on the anode-cathode bias modulates the depletion capacitance and appears directly as FM sidebands or phase noise on the VCO/tanker output. Use an RC or pi filter (for example 10k in series plus 100 nF and 1 uF shunt caps) between the tuning source and the diode, and route the tuning line away from clock and switching-regulator traces on the PCB.
Do not design new products around this part: the NXP datasheet explicitly marks the BB202 as NOT RECOMMENDED FOR NEW DESIGNS. If the BB202,135 is used for legacy repair, remember the two-terminal SOD-523 has no polarity-marking asymmetry as obvious as larger diodes - verify cathode orientation (pin 1) with the board silkscreen. The series DC-blocking capacitor in the tank should be at least 10x the maximum varicap capacitance (i.e. >300 pF) so it does not load the tuning range.
Compliance Information
The ,135 ordering suffix conventionally denotes the lead-free RoHS-compliant version in NXP ordering codes, but no verified compliance certificate was present in the provided data - confirm on the NXP product page before procurement.
