Analog Devices Inc. HMC778LP6CETR

Overview

HMC778LP6CETR 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 50 MHz reference input, achieves -106 dBc/Hz in-band phase noise at 10 kHz offset (integer mode), and features 24-bit frequency resolution (3 Hz typical step size). It is used in microwave point-to-point radios and FMCW radar systems requiring ultra-low jitter and fast frequency settling.

For engineers reviewing the HMC778LP6CETR datasheet, HMC778LP6CETR pinout, HMC778LP6CETR application, or HMC778LP6CETR equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, application-specific implementation guidance, and two confirmed alternative synthesizers for similar high-frequency fractional-N PLL use cases.

Technical Context

The HMC778LP6CETR implements a delta-sigma modulator-based fractional-N architecture with integrated VCO, enabling fine frequency resolution (3 Hz typ.) and low spurious content (-65 dBc fractional spurs). Its dual-mode operation supports both integer and fractional synthesis with programmable reference path (DC–350 MHz) and configurable charge pump gain (0.02–2.5 mA/rad).

It integrates RF/2 divider (16-bit, even-only above 4 GHz), external trigger input (TRIG), lock detect/data output (LD_SDO), and frequency sweeping capability. The device requires separate 5 V (VCO/charge pump) and 3.3 V (analog/digital) supplies, with strict decoupling requirements on AVDD, RVDD, and VDDPD to maintain phase noise integrity.

Key Specifications

Pinout & Package

Package: 40-lead, RoHS-compliant leadless QFN (6 × 6 mm, MSL3), with exposed ground paddle requiring soldering to PCB RF ground per Hittite Application Note.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC830LP6CE and ADF4371BCPZ, the HMC778LP6CETR uniquely combines X-band coverage, integrated frequency sweeping, external trigger support, and ultra-low in-band phase noise-making it optimal for radar and secure comms where deterministic frequency agility and spectral purity are co-required.

Availability

HMC778LP6CETR is available at Aetrix Electronics and suitable for microwave point-to-point radios, FMCW radar systems, and phased array applications requiring stable component supply across extended temperature ranges (-40°C to +85°C) and long production lifecycles.

Supply support for HMC778LP6CETR 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, emphasizing precision microwave ICs for defense, aerospace, and communications infrastructure.

The HMC778LP6CETR belongs to Hittite's "PLLs with Integrated VCO" product line, designed specifically for X-band wireless infrastructure and radar systems demanding single-chip frequency synthesis with minimal external components and deterministic timing control.

FAQ

What is the operating temperature range for the HMC778LP6CETR?

The HMC778LP6CETR is rated 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 case temperature is 123°C-well below the 135°C threshold for 1 million-hour MTTF. This makes the HMC778LP6CETR suitable for outdoor microwave radios and vehicle-mounted radar units.

Does the HMC778LP6CETR support both integer and fractional-N synthesis modes?

Yes, the HMC778LP6CETR supports both integer and fractional-N synthesis modes. In integer mode, the phase detector rate can reach up to 115 MHz; in fractional mode, it supports up to 100 MHz (Mode B). The device uses a delta-sigma modulator to achieve 24-bit frequency resolution and ultra-fine step sizes (~3 Hz), while maintaining low spurious content (-65 dBc typical fractional spurs).

How is the RF output of the HMC778LP6CETR configured and matched?

The HMC778LP6CETR RF output (Pin 38, RFOUT) is AC-coupled and delivers +9 dBm across 9.6–10.8 GHz. It requires external 50 Ω matching using a series DC-blocking capacitor (e.g., 100 pF) and optional shunt inductor for broadband flatness. The datasheet specifies sub-harmonic suppression of 33 dBc and 2nd/3rd harmonic rejection of 25 dBc and 35 dBc respectively-enabling direct connection to balanced mixers without additional filtering.

Can the HMC778LP6CETR be used for frequency modulation or phase modulation?

Yes, the HMC778LP6CETR supports both frequency and phase modulation via its VTUNE pin (Pin 6) and digital register controls. The integrated frequency sweeper enables linear chirps, while external triggering (Pin 36, TRIG) allows precise hop timing. Phase modulation is implemented through fractional-N register updates synchronized to the reference clock, supporting formats like π/4-DQPSK in secure comms links.

What power supply configurations are required for the HMC778LP6CETR?

The HMC778LP6CETR requires three independent supply domains: +5 V for VCO (Pins 8, 40) and charge pump (Pins 16, 17); +3.3 V for analog circuitry (Pins 15, 19, 21, 25, 34); and +3.3 V for digital I/O (Pins 31, 32). Each domain has strict current limits (e.g., 265 mA max on 5 V VCO rail) and demands dedicated decoupling-especially VDDPD, whose noise directly impacts phase detector jitter.