Analog Devices Inc. HMC778LP6CE

Overview

HMC778LP6CE from Analog Devices (formerly Hittite Microwave) is a fully integrated Fractional-N PLL frequency synthesizer with on-die VCO, operating from 9.6 GHz to 10.8 GHz. It delivers +9 dBm RF output power, supports 350 MHz reference input, enables 3 Hz frequency resolution in fractional mode, and features triggered frequency hopping and phase modulation for microwave radio and radar systems.

For engineers reviewing the HMC778LP6CE datasheet, HMC778LP6CE pinout, HMC778LP6CE application, or HMC778LP6CE equivalent, this device is selected for high-stability, low-phase-noise local oscillator generation in FMCW radar, phased array transceivers, and VSAT radios where sub-100 fs jitter and <−140 dBc/Hz @ 1 MHz offset are required.

Technical Context

The HMC778LP6CE integrates a delta-sigma fractional-N synthesizer, high-linearity charge pump, and broadband VCO in a single 6 × 6 mm QFN. Its architecture supports both integer and fractional modes with programmable loop bandwidth up to 100 kHz, enabling fast 100 MHz frequency settling in 195 µs while maintaining −106 dBc/Hz in-band phase noise at 10 kHz offset.

It implements double-buffered register loading, external CMOS trigger input (Pin 36), and integrated frequency sweeper functionality. The VCO tuning sensitivity is 165 MHz/V at VTUNE = 6 V, with pulling <5 MHz peak-to-peak into 2:1 VSWR and pushing <30 MHz/V - critical for stable operation in temperature-varying RF front ends.

Key Specifications

Pinout & Package

Package: 40-lead, RoHS-compliant, leadless QFN (6 × 6 mm, 0.5 mm pitch), MSL3 rated, with exposed ground paddle requiring solder connection to PCB RF ground plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fractional-N PLL with integrated VCO applications.

Compared with HMC778LP6CE, HMC739LP4E offers lower cost and smaller size but sacrifices Ku-band coverage and advanced modulation features; ADF4371BCPZ provides wider frequency range and embedded power management but increases board area and complexity - making HMC778LP6CE optimal for compact, high-performance Ku-band radar and radio designs requiring deterministic triggering.

Availability

HMC778LP6CE is available at Aetrix Electronics and suitable for VSAT terminals, FMCW radar modules, and phased array antenna systems requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for HMC778LP6CE 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 for defense, aerospace, and communications infrastructure.

The HMC778LP6CE belongs to Hittite's "PLLs with Integrated VCO" product line, designed specifically for high-frequency, low-phase-noise local oscillator generation in radar, satellite, and point-to-point wireless systems.

FAQ

What is the operating temperature range for the HMC778LP6CE?

The HMC778LP6CE is specified for continuous operation from −40°C to +85°C ambient temperature. Its thermal resistance (junction-to-ground paddle) is 24.7°C/W, and nominal junction temperature at +85°C ambient is 123°C - well within the 135°C MTTF limit. This makes the HMC778LP6CE suitable for outdoor base stations, vehicle-mounted radar, and industrial environments without forced cooling.

Does the HMC778LP6CE support both integer and fractional-N synthesis modes?

Yes, the HMC778LP6CE supports both integer and fractional-N synthesis modes. In integer mode, it achieves −106 dBc/Hz phase noise at 10 kHz offset (Fref = 50 MHz, Fvco = 10.2 GHz); in fractional mode, it delivers −102 dBc/Hz at the same condition with 3 Hz typical frequency resolution. Mode selection is configured via SPI register settings, and both modes share the same 350 MHz max reference input capability.

How is the RF output of the HMC778LP6CE configured and matched?

The HMC778LP6CE RF output (Pin 38, RFOUT) is AC-coupled and delivers +9 dBm typical into a 50 Ω load. It requires an external DC-blocking capacitor (e.g., 100 pF) and optional matching network to optimize return loss and harmonic suppression. The datasheet specifies −25 dBc 2nd harmonic and −35 dBc 3rd harmonic, confirming suitability for direct connection to mixers without additional filtering in many Ku-band architectures.

Can the HMC778LP6CE perform phase modulation, and how is it implemented?

Yes, the HMC778LP6CE supports phase modulation via its VTUNE (Pin 6) port and digital modulation registers. The VCO exhibits 165 MHz/V tuning sensitivity at 6 V, enabling analog phase modulation with bandwidth dependent on the drive source impedance. Digital phase modulation is also supported through the fractional-N modulator's sigma-delta engine, allowing programmable phase offsets and modulation patterns synchronized to the TRIG input.

What is the recommended PCB layout practice for the HMC778LP6CE ground paddle?

The exposed ground paddle of the HMC778LP6CE must be soldered to a solid, low-impedance RF ground plane using ≥9 thermal vias (0.3 mm diameter, spaced ≤1 mm apart) connecting to inner and bottom ground layers. Per Hittite Application Note, all ground leads (Pins 2–5, 7, 37, 39) and the paddle must be tied together with minimal trace length to avoid resonance and ensure <−140 dBc/Hz open-loop phase noise performance.