Infineon BB837E6327 Hyperabrupt Tuning Varactor Diode Datasheet and Application Notes

The Infineon BB837E6327 is a silicon hyperabrupt junction tuning varactor diode, specifically engineered for high-performance applications in electronic tuning systems. As a key component in voltage-controlled oscillators (VCOs), phase-locked loops (PLLs), and RF filters, this diode excels where wide tuning range and high tuning linearity are critical. Its hyperabrupt junction characteristic allows for a larger capacitance change per volt compared to conventional abrupt junction varactors, making it ideal for broadband tuning circuits such as those in television tuners, cellular base stations, and other wireless communication systems.

A primary feature highlighted in the datasheet is its capacitance ratio (C2/C30) of 3.8 typical at bias voltages of 2V and 30V, with a nominal capacitance of 38pF at 1MHz and 4V reverse bias. This high ratio is essential for achieving a broad tuning range in oscillator designs. The diode is packaged in a SOD-323 miniature plastic package, which is suitable for high-density surface-mount assembly. The operating temperature range spans from -65°C to +150°C, ensuring reliability under harsh environmental conditions.

Application Notes and Circuit Design Considerations

When implementing the BB837E6327, proper RF circuit layout is paramount. Minimizing stray capacitance and parasitic inductance is necessary to preserve the diode's tuning performance. The application notes emphasize using a DC blocking capacitor in series with the varactor to isolate the bias voltage from the RF signal path. Additionally, a high-value RF choke resistor is recommended in the bias line to prevent RF energy from leaking into the control voltage source, which could otherwise lead to frequency instability or undesired modulation.

For optimal linearity, the control voltage should be supplied from a low-noise, well-regulated source, as any noise or ripple on this line will directly cause unwanted frequency modulation. In VCO designs, the diode’s quality factor (Q) is crucial—it remains high (typically above 300 at 1MHz and 50 at 500MHz), which helps in achieving low phase noise oscillators. Designers are advised to simulate the entire resonant circuit, accounting for the varactor’s voltage-dependent capacitance, to predict tuning sensitivity (MHz/Volt) accurately.

ICGOODFIND: The Infineon BB837E6327 hyperabrupt varactor diode is a superior choice for applications demanding a wide tuning range and excellent linearity, offering robust performance in compact consumer and industrial RF systems.

Keywords: Varactor Diode, Hyperabrupt Junction, Voltage-Controlled Oscillator, Capacitance Ratio, RF Tuning