NXP Semiconductors BB178,335

Overview

BB178,335 from NXP Semiconductors is a planar technology variable capacitance diode (varactor) in an ultra-small SOD523 (SC-79) surface-mount package, designed for electronic tuning in VHF band B applications up to 460 MHz and Voltage-Controlled Oscillators (VCOs). It delivers Cd(1 V) = 34.65–42.35 pF, Cd(28 V) = 2.361–2.754 pF, capacitance ratio Cd(1 V)/Cd(28 V) = 13.5–15, series resistance rs = 0.65–0.8 Ω at 100 MHz, and matching accuracy ≤2 % via Direct Matching Assembly (DMA).

For engineers reviewing the BB178,335 datasheet, BB178,335 pinout, BB178,335 application, or BB178,335 equivalent, this varactor is selected for high-linearity VHF tuning where tight capacitance matching, low series resistance, and stable temperature coefficient across 0–85 °C are critical design requirements.

Technical Context

The BB178,335 operates as a reverse-biased junction capacitor whose depletion width-and thus capacitance-varies nonlinearly with applied DC voltage. Its planar silicon structure enables precise doping control for consistent C-V slope and low rs, supporting stable oscillator pulling and fine-tuning resolution in RF front-ends.

It is characterized at Tj = 25 °C (with data extended to 0–85 °C), exhibits IR ≤10 nA at VR = 30 V, and maintains Cd matching ≤2 % across sequences of 10 diodes using gliding DMA-enabling matched-pair use in differential VCO topologies without external trimming.

Key Specifications

Pinout & Package

SOD523 (SC-79) plastic surface-mounted package: 2-terminal, ultra-compact outline (1.25 × 0.85 × 0.65 mm), cathode marked by bar on top surface.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar varactor diode applications.

Compared with BBY52,115 and SMV1232-011, the BB178,335 uniquely combines VHF-optimized C-V linearity, ≤2 % DMA matching, and sub-0.8 Ω series resistance-making it the preferred choice for high-yield, low-phase-noise VCO manufacturing where matched-pair reliability is mandatory.

Availability

BB178,335 is available at Aetrix Electronics and suitable for VHF television tuners, voltage-controlled oscillators, FM radio front-ends, and RF filter tuning modules requiring stable component supply and guaranteed matching performance.

Supply support for BB178,335 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 applications.

The BB178,335 belongs to NXP's RF varactor diode product line, engineered specifically for high-precision electronic tuning in VHF broadcast and communications systems where matching, linearity, and miniaturization are essential.

FAQ

What is the primary function of the BB178,335 in RF circuits?

The BB178,335 functions as a voltage-controlled variable capacitance diode (varactor), used to tune resonant frequencies in VHF circuits such as television tuners and VCOs. Its capacitance changes predictably with reverse bias voltage, enabling precise electronic frequency adjustment without mechanical components. The BB178,335 achieves this with high linearity and ≤2 % matching via Direct Matching Assembly, making it especially valuable in production-grade RF designs.

What is the maximum reverse voltage rating for the BB178,335?

The BB178,335 has an absolute maximum reverse voltage (VR) rating of 32 V and a peak reverse voltage (VRM) of 35 V when used with a 10 kΩ series resistor. Operation beyond these limits risks permanent junction damage. For reliable long-term performance in VCO bias networks, NXP recommends staying below 28 V-where the BB178,335 is fully characterized for capacitance and matching behavior.

How does the BB178,335 achieve its 2 % matching specification?

The BB178,335 achieves ≤2 % capacitance matching through a two-stage process: first, precision gliding matching during wafer-level testing, then final pairing using Direct Matching Assembly (DMA). This ensures matched diode pairs exhibit near-identical C-V curves across 1–28 V, critical for differential VCO architectures. The BB178,335 datasheet confirms this performance applies to sequences of 10 diodes, not just isolated pairs.

Is the BB178,335 suitable for automotive applications?

No-the BB178,335 is not automotive-qualified. NXP explicitly states in the datasheet that unless otherwise specified, its products-including the BB178,335-are not tested or warranted for automotive use. It lacks AEC-Q200 qualification, extended temperature validation beyond −55 to +125 °C, or automotive-grade reliability screening. For automotive VCOs, designers must select an AEC-Q200 qualified alternative, as the BB178,335 is intended for consumer VHF tuners and industrial RF modules.

What package type does the BB178,335 use, and how is polarity identified?

The BB178,335 uses the SOD523 (SC-79) ultra-small plastic surface-mount package, measuring 1.25 × 0.85 × 0.65 mm. Polarity is identified by a marking bar on the top surface, which denotes Pin 1 (cathode); Pin 2 (anode) is unmarked and located opposite the bar. This compact 2-terminal outline minimizes parasitic inductance-critical for stable VHF operation-and is compatible with standard SMT reflow profiles.