Analog Devices Inc. 105706-HMC391LP4

Overview

105706-HMC391LP4 from Analog Devices (formerly Hittite Microwave) is a GaAs InGaP HBT MMIC voltage-controlled oscillator with integrated buffer amplifier, operating from 3.9 to 4.45 GHz. It delivers +5.0 dBm output power at +3 V / 30 mA, achieves −106 dBc/Hz phase noise at 100 kHz offset, and requires no external resonator. It is used in microwave radio transceivers where stable, low-noise local oscillation is critical.

For engineers reviewing the 105706-HMC391LP4 datasheet, 105706-HMC391LP4 pinout, 105706-HMC391LP4 application, or 105706-HMC391LP4 equivalent, key selection criteria include tuning voltage range (0–10 V), pulling tolerance (8 MHz pp into 2.0:1 VSWR), pushing sensitivity (16 MHz/V), frequency drift (0.5 MHz/°C), and QFN-24 package thermal resistance (333 °C/W).

Technical Context

The 105706-HMC391LP4 integrates monolithic resonator, negative resistance device, varactor diode, and buffer amplifier on a single GaAs die, eliminating external tuning components. Its all-MMIC architecture ensures robust phase noise performance across −40°C to +85°C, shock, vibration, and process variation.

It operates from a single +3 V supply with 30 mA typical current draw, and features a dedicated VTUNE input (0–10 V) with 10 μA leakage, while RFOUT is AC-coupled and requires 50 Ω termination. The exposed paddle must be soldered to RF ground per Hittite's recommended land pattern.

Key Specifications

Pinout & Package

24-lead leadless QFN package (4 × 4 mm, 0.5 mm pitch) with exposed ground paddle. All ground leads (pins 1–14, 17–19, 21, 23, 24) and paddle must be soldered to PCB RF ground per Hittite Application Note land pattern.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC391LP4E, the 105706-HMC391LP4 offers identical RF performance but uses Sn/Pb finish and 235°C reflow; versus HMC513LP5, it trades bandwidth and noise for smaller size and lower power, making it optimal for space-constrained C-band designs.

Availability

105706-HMC391LP4 is available at Aetrix Electronics and suitable for VSAT transceivers, microwave radio IF synthesis, radio altimeters, and test equipment requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for 105706-HMC391LP4 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

Analog Devices, Inc. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and RF ICs for precision signal processing.

The 105706-HMC391LP4 belongs to ADI's legacy Hittite Microwave VCO product line, engineered for microwave communication systems demanding low phase noise, wide tuning range, and rugged monolithic integration.

FAQ

What is the absolute maximum tuning voltage for the 105706-HMC391LP4?

The absolute maximum tuning voltage for the 105706-HMC391LP4 is +11 V DC. Exceeding this voltage may cause permanent damage to the internal varactor diode. The recommended operating range is 0–10 V, which fully covers the 3.9–4.45 GHz output band. Always limit VTUNE with clamping circuitry in PLL designs where transient overshoot is possible. The 105706-HMC391LP4 datasheet specifies 10 μA max leakage at rated VTUNE, confirming tight control of junction integrity within this window.

Does the 105706-HMC391LP4 require external matching components at RFOUT?

No, the 105706-HMC391LP4 RFOUT is internally matched to 50 Ω and AC-coupled, so no external matching network is required. However, a DC-blocking capacitor (e.g., 100 pF) must be placed in series before connecting to downstream circuitry. The 105706-HMC391LP4 evaluation board uses an SMA connector directly mounted to the RFOUT pad, confirming its readiness for 50 Ω system integration without tuning stubs or baluns.

What is the thermal resistance (θ_JA) of the 105706-HMC391LP4 package?

The thermal resistance from junction to ambient (θ_JA) for the 105706-HMC391LP4 is not specified in the datasheet, but junction-to-ground-paddle (θ_JG) is 333 °C/W. Effective thermal management requires soldering the exposed paddle and all ground pins to a multi-layer PCB ground plane using ≥6 thermal vias. The 105706-HMC391LP4 dissipates ~90 mW (3 V × 30 mA), so proper grounding keeps junction temperature within −40°C to +85°C operating limits.

Can the 105706-HMC391LP4 operate from a 2.75 V supply?

Yes, the 105706-HMC391LP4 operates from 2.75 V to 3.25 V, with typical supply current dropping to 22 mA at 2.75 V and rising to 39 mA at 3.25 V. Output power decreases slightly (~0.5 dB) at lower Vcc, and tuning sensitivity shifts modestly-verified in the "Frequency vs. Vcc" plot on page 12-31. System designers using 2.75 V rails should verify lock range and phase noise in their specific PLL configuration, as the 105706-HMC391LP4 maintains full functionality across this range.

Is the 105706-HMC391LP4 pin-compatible with the HMC391LP4E?

Yes, the 105706-HMC391LP4 is mechanically and electrically pin-compatible with the HMC391LP4E. Both share identical 24-lead 4×4 mm QFN footprints, pin functions, and electrical specifications-including frequency range, output power, phase noise, and supply requirements. The only differences are RoHS compliance (HMC391LP4E uses 100% matte Sn), MSL rating (260°C vs. 235°C), and marking. No PCB changes are required when substituting the 105706-HMC391LP4 for HMC391LP4E or vice versa.