**High-Performance 18 GHz VCO with Integrated Buffer: HMC716LP3ETR Datasheet and Application Circuit Design Guide**

The demand for stable and high-frequency signal generation is paramount in modern communication systems, test equipment, and radar applications. The **HMC716LP3ETR**, a Voltage Controlled Oscillator (VCO) with an integrated buffer amplifier from Analog Devices, stands out as a critical component designed to meet these rigorous requirements. Operating across a **wide frequency range of 16.5 to 18.5 GHz**, this VCO delivers exceptional performance in a compact, surface-mount package.

**Key Features and Electrical Characteristics**

The HMC716LP3ETR is engineered for high performance. Its integrated architecture combines a fundamental VCO core with a buffer amplifier, which provides **excellent isolation** from load variations, ensuring frequency stability. Key parameters from the datasheet include a typical **output power of +12 dBm**, which is sufficient to drive mixers or power amplifiers directly. The phase noise performance is a critical figure of merit for any oscillator; this VCO achieves an outstanding **-112 dBc/Hz typical phase noise at 100 kHz offset**, minimizing signal degradation in sensitive receivers.

The tuning voltage range of 0 to +13V allows for precise frequency control, with a typical tuning sensitivity of 65 MHz/V. The device requires a single positive supply of +5V, drawing a nominal current of 120 mA, making its power consumption manageable for most systems. The **RoHS-compliant 3x3 mm QFN package** ensures easy integration into high-density PCB designs while providing effective thermal dissipation.

**Application Circuit Design Guide**

Implementing the HMC716LP3ETR successfully requires careful attention to the application circuit and board layout. The following design considerations are crucial for optimal performance:

1. **Power Supply Decoupling:** Stable, low-noise power is non-negotiable. Use a combination of bulk, ceramic, and RF decoupling capacitors placed as close as possible to the VCC and VCC_BUF pins. A ferrite bead in series can further suppress board-level noise.

2. **PCB Material and Layout:** Employ **low-loss, high-frequency laminate materials** like Rogers RO4003C for the RF sections of the board. The ground plane must be solid and uninterrupted directly beneath the component. Ensure all ground pins are soldered directly to the board using multiple vias to create a low-inductance path to the ground plane.

3. **Tuning Voltage Line:** The Vtune input is highly sensitive. It must be isolated from noisy digital signals and driven by a low-noise, high-purity analog tuning source. A simple RC low-pass filter on this line can effectively suppress noise that would otherwise cause unwanted FM modulation and degrade phase noise.

4. **RF Output Matching:** The RF output (RFout) is internally matched to 50 ohms. The output transmission line should be a controlled impedance 50-ohm microstrip line leading directly to an SMA connector or the next active component. Avoid sharp bends and keep the line as short as possible.

5. **Heat Dissipation:** Although the package is efficient at transferring heat, ensuring adequate thermal relief on the PCB is good practice. The exposed paddle must be soldered to a central ground pad with sufficient vias to act as a heat sink.

A typical application circuit is straightforward, primarily focusing on clean power delivery and a stable tuning voltage. The output can be directly connected to a 50-ohm load or measurement equipment without external matching networks, simplifying design.

**ICGOO**D**FIND Summary**

The **HMC716LP3ETR** is a premier solution for **high-frequency signal generation**, integrating a VCO and buffer to deliver high output power and superior phase noise. Its robust performance and relatively simple application requirements make it an excellent choice for designers working on next-generation microwave systems. Careful attention to PCB layout and power supply integrity is the key to unlocking its full potential.

**Keywords:** **Voltage Controlled Oscillator (VCO)**, **18 GHz**, **Phase Noise**, **Integrated Buffer**, **Microwave Design**.