Analog Devices Inc. 105706-HMC385LP4

Overview

105706-HMC385LP4 from Analog Devices (formerly Hittite Microwave) is a GaAs InGaP HBT MMIC voltage-controlled oscillator with integrated resonator and buffer amplifier, operating from 2.25 to 2.5 GHz. It delivers +4.5 dBm RF output at 3 V / 35 mA, achieves −115 dBc/Hz phase noise at 100 kHz offset, and requires no external resonator. It is used in wireless infrastructure transceivers for local oscillator synthesis.

For engineers reviewing the 105706-HMC385LP4 datasheet, 105706-HMC385LP4 pinout, 105706-HMC385LP4 application, or 105706-HMC385LP4 equivalent, key selection criteria include tuning voltage range (0–10 V), frequency pulling tolerance (2.0 MHz pp into 2.0:1 VSWR), pushing sensitivity (−2 MHz/V), thermal drift (0.25 MHz/°C), and QFN-16 package compatibility with RF ground paddle requirements.

Technical Context

The 105706-HMC385LP4 integrates monolithic negative resistance devices, varactor diodes, and a buffer amplifier on a single GaAs die, enabling stable oscillation without external LC tanks or crystal references. Its architecture eliminates discrete tuning components while maintaining low phase noise across −40°C to +85°C.

It operates from a single 3 V supply with 35 mA typical current draw and supports modulation via the VTUNE port, whose bandwidth depends on source impedance. The exposed ground paddle and 16-pin QFN package are optimized for RF grounding and thermal dissipation in high-frequency PCB layouts.

Key Specifications

Pinout & Package

105706-HMC385LP4 is housed in a leadless 4×4 mm QFN-16 package with an exposed RF/DC ground paddle. All ground pins (15, 17–19, 21, 23–24) and the paddle must be soldered to a continuous PCB ground plane using multiple vias.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC385LP4E, the 105706-HMC385LP4 offers identical RF performance but requires Sn/Pb soldering processes; compared with HMC513LP5, it provides lower-frequency coverage in a smaller package but lacks the higher output power and extended tuning range needed for millimeter-wave adjacent bands.

Availability

105706-HMC385LP4 is available at Aetrix Electronics and suitable for wireless infrastructure, test equipment, and military communications systems requiring stable component supply with guaranteed long-term availability and controlled obsolescence management.

Supply support for 105706-HMC385LP4 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 acquired Hittite Microwave in 2014 and maintains its high-frequency RF product portfolio, specializing in microwave ICs, VCOs, PLLs, and integrated transceivers for demanding communication systems.

The 105706-HMC385LP4 belongs to Hittite's legacy MMIC VCO family, designed specifically for low-phase-noise, surface-mount local oscillator generation in infrastructure and defense-grade RF subsystems.

FAQ

What is the operating temperature range for the 105706-HMC385LP4?

The 105706-HMC385LP4 operates from −40°C to +85°C, with specified electrical performance (including phase noise, output power, and tuning linearity) guaranteed across this full industrial temperature range. Frequency drift is characterized at 0.25 MHz/°C, and phase noise remains stable at −115 dBc/Hz @ 100 kHz offset over temperature.

Does the 105706-HMC385LP4 require external tuning components?

No, the 105706-HMC385LP4 does not require external resonators, varactors, or tank circuits. Its monolithic GaAs InGaP HBT structure integrates the oscillator core, negative resistance device, varactor diode, and buffer amplifier, enabling full 2.25–2.5 GHz operation with only a DC blocking capacitor on RFOUT and proper grounding of the exposed paddle.

What is the recommended PCB layout practice for the 105706-HMC385LP4 ground paddle?

The exposed ground paddle of the 105706-HMC385LP4 must be soldered to a solid RF/DC ground plane using ≥8 thermal vias (0.3 mm diameter, spaced ≤1 mm apart). Per Hittite Application Note, the land pattern should match the 4×4 mm QFN outline with solder mask defined pads, and all ground pins (15, 17–19, 21, 23–24) must connect directly to the same ground plane.

How does supply voltage variation affect the 105706-HMC385LP4 output frequency?

Supply pushing sensitivity for the 105706-HMC385LP4 is −2 MHz/V at VTUNE = +5 V. With nominal VCC = 3.0 V ±0.25 V, this translates to a maximum frequency shift of ±0.5 MHz due to supply ripple or droop-well within the 250 MHz total tuning range and manageable via regulated LDO filtering.

Can the 105706-HMC385LP4 be used in phase-locked loop (PLL) synthesizers?

Yes, the 105706-HMC385LP4 is commonly used as the VCO core in integer-N and fractional-N PLL synthesizers. Its 0–10 V tuning range, low pushing/pulling, and −115 dBc/Hz phase noise make it compatible with standard charge-pump PLL ICs such as ADF4159 or LMX2594 when paired with appropriate loop filter design and reference clock conditioning.