Analog Devices Inc. 110227-HMC508LP5

Overview

HMC508LP5 from Analog Devices (formerly Hittite Microwave) is a GaAs InGaP HBT monolithic voltage-controlled oscillator with dual RF outputs: fundamental (7.3–8.2 GHz) and half-frequency (3.65–4.1 GHz), delivering +15 dBm typical output power at +5 V supply, −116 dBc/Hz phase noise @ 100 kHz offset, and housed in a 32-lead 5×5 mm QFN package - used in VSAT radios and point-to-point microwave links.

For engineers reviewing the HMC508LP5 datasheet, HMC508LP5 pinout, HMC508LP5 application, or HMC508LP5 equivalent, key selection criteria include its integrated resonator architecture, Fo/Fo/2 dual-band capability, ±8 MHz peak-to-peak pulling tolerance, 10 MHz/V pushing coefficient, and MSL3 reflow compatibility - all critical for stable microwave transceiver design.

Technical Context

The HMC508LP5 implements a fully monolithic GaAs InGaP HBT oscillator core with on-die varactor tuning and integrated resonators, eliminating external LC tanks or crystal references. Its dual-output topology routes fundamental RFOUT (Pin 19) and Fo/2 (Pin 12) via separate AC-coupled paths, each with ≥2 dB return loss and harmonic suppression of ≥20 dBc (2nd) and ≥35 dBc (3rd).

Tuning is achieved via VTUNE (Pin 29) over 2–13 V, delivering 7.3–8.2 GHz linear frequency sweep with 10 MHz/V sensitivity and <1.0 MHz/°C drift. Supply regulation is strict: Vcc (Pin 21) requires +5.0 V ±0.25 V, drawing 240 mA typical, with thermal resistance of 35 °C/W to ground paddle.

Key Specifications

Pinout & Package

The HMC508LP5 is housed in a leadless 5×5 mm QFN package with 32 terminals and an exposed thermal/RF ground paddle. All ground pins (5, 11, paddle) and the backside paddle must be soldered to a continuous PCB ground plane using multiple vias for optimal RF performance and thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC508LP5, HMC509LP5 offers superior phase noise but sacrifices half-frequency output, while ADF4351BCPZ adds programmability and flexibility at the cost of increased design effort, external components, and reduced integration density.

Availability

HMC508LP5 is available at Aetrix Electronics and suitable for VSAT radio development, point-to-point microwave equipment, and military communications hardware requiring stable component supply, consistent lot-to-lot RF performance, and long-term obsolescence management.

Supply support for HMC508LP5 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 portfolio, specializing in GaAs, GaN, and SiGe MMICs for defense, aerospace, and wireless infrastructure.

The HMC508LP5 belongs to Hittite's legacy MMIC VCO product line, engineered for microwave radio systems demanding monolithic integration, wide tuning range, and exceptional phase stability without external resonators.

FAQ

What is the operating temperature range for the HMC508LP5?

The HMC508LP5 is specified for continuous operation from −40 °C to +85 °C. Performance data-including frequency range, output power, and phase noise-is guaranteed across this range, with plots provided for −40 °C, +25 °C, and +85 °C in the datasheet. The device's monolithic GaAs construction ensures stable behavior under thermal cycling, critical for outdoor microwave radios where ambient extremes occur.

Does the HMC508LP5 require external matching components?

No, the HMC508LP5 requires no external matching components. Its monolithic design integrates resonators, negative resistance devices, and varactor diodes, with both RFOUT and RFOUT/2 outputs internally matched to 50 Ω and AC-coupled. Only DC blocking capacitors (e.g., 100 pF at RFOUT) and supply decoupling (100 pF + 1000 pF) are needed per the recommended evaluation board layout.

What is the meaning of "Fo/2 output" in the HMC508LP5 datasheet?

"Fo/2 output" refers to the HMC508LP5's second dedicated RF port (Pin 12) that delivers a clean, AC-coupled signal at exactly half the fundamental oscillation frequency - i.e., 3.65–4.1 GHz when Fo = 7.3–8.2 GHz. This is generated natively within the MMIC core, not via external division, preserving phase noise and eliminating added jitter or spurs.

How is the exposed paddle on the HMC508LP5 package used in PCB layout?

The exposed metal paddle on the HMC508LP5 must be soldered directly to a solid RF/DC ground plane on the PCB using multiple thermal vias (≥6 recommended). It serves as the primary thermal conduction path (35 °C/W) and RF ground reference. Per Hittite Application Note, the land pattern must match the outline drawing - undersized or floating paddle connections cause elevated junction temperature and degraded phase noise.

Is the HMC508LP5 pin-compatible with the HMC508LP5E variant?

Yes, the HMC508LP5 and HMC508LP5E share identical pinout, footprint, and electrical specifications. The only differences are RoHS compliance (100% matte Sn finish vs. Sn/Pb), MSL3 reflow profile (260 °C peak vs. 235 °C), and marking (H508 + 4-digit lot). Both variants are functionally interchangeable in existing designs with appropriate process validation.