Analog Devices Inc. HMC839LP6CETR

Overview

HMC839LP6CETR from Analog Devices (formerly Hittite Microwave) is a fully integrated Fractional-N PLL with on-die VCO, operating across three RF bands: 1050–1205 MHz (f_VCO/2), 2100–2410 MHz (f_VCO), and 4200–4820 MHz (2f_VCO). It delivers ultra-low phase noise (−112 dBc/Hz typ. in-band), <180 fs RMS jitter, 24-bit frequency resolution (3 Hz typ.), and supports exact-frequency mode for precise synthesizer tuning in cellular infrastructure and test equipment.

For engineers reviewing the HMC839LP6CETR datasheet, HMC839LP6CETR pinout, HMC839LP6CETR application, or HMC839LP6CETR equivalent, this device is selected for high-stability RF synthesis requiring sub-100 kHz loop bandwidths, fast frequency hopping via cycle-slip prevention, and tri-band harmonic flexibility without external multipliers.

Technical Context

The HMC839LP6CETR integrates a low-noise delta-sigma fractional-N PLL core with an autocalibrating tri-band VCO, precision charge pump (0.02–2.54 mA), and low-noise reference path divider. Its phase detector includes cycle-slip prevention (CSP) to reduce settling time during frequency transitions.

It supports three output modes-fundamental (f_VCO), divide-by-2 (f_VCO/2), and doubler (2f_VCO)-with independent RF output power levels (10 dBm typ. at f_VCO/2, 7 dBm at f_VCO, −4 dBm at 2f_VCO) and harmonic suppression down to −58 dBc (4th harmonic, f_VCO/2 mode).

Key Specifications

Pinout & Package

40-lead, 6×6 mm LFCSP package (HMC839LP6CETR) with exposed ground paddle; RoHS-compliant, MSL1, thermal resistance 20 °C/W (junction-to-paddle). All ground leads and paddle must be soldered 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 HMC839LP6CETR, HMC838LP6CE offers lower cost but sacrifices tri-band flexibility and doubler functionality, while ADF4371BCPZ extends frequency reach and FOM at the expense of power and layout complexity - making HMC839LP6CETR optimal for mid-band 4G/5G infrastructure where 1.05–4.82 GHz coverage and thermal efficiency are prioritized.

Availability

HMC839LP6CETR is available at Aetrix Electronics and suitable for cellular infrastructure, communications test equipment, and phased array systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for HMC839LP6CETR 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 line, specializing in microwave/mmWave ICs for defense, communications, and instrumentation.

The HMC839LP6CETR belongs to Hittite's integrated PLL+VCO family, designed specifically for compact, high-performance RF synthesis in space-constrained wireless infrastructure where phase noise, jitter, and multi-band agility are critical.

FAQ

What RF output modes does the HMC839LP6CETR support, and how are they configured?

The HMC839LP6CETR supports three RF output modes: fundamental (f_VCO), divide-by-2 (f_VCO/2), and doubler (2f_VCO). Mode selection is controlled by internal register settings and external RF matching network configuration. In doubler mode, pins 28 (RF_N) and 29 (RF_P) must be shorted together per datasheet specification. Each mode delivers distinct output power (e.g., 10 dBm typ. at f_VCO/2) and harmonic content, enabling flexible system-level frequency planning without external multipliers. The HMC839LP6CETR's tri-band VCO ensures all modes remain functional across its full 1.05–4.82 GHz coverage.

How does the cycle-slip prevention (CSP) feature improve frequency agility in the HMC839LP6CETR?

The HMC839LP6CETR's cycle-slip prevention (CSP) circuitry actively monitors phase detector output and dynamically adjusts charge pump behavior to avoid loss of lock during large frequency steps. This reduces settling time by over 3× compared to standard fractional-N PLLs - critical for TDD-LTE base stations and radar systems requiring sub-10 µs hop times. CSP operates transparently under firmware control and does not require user calibration. For HMC839LP6CETR deployments in dynamic spectrum access or beamforming applications, CSP ensures reliable, deterministic frequency transitions without spurious lock-loss recovery delays.

What is the significance of the −227 dBc/Hz Figure of Merit (FOM) for the HMC839LP6CETR?

The −227 dBc/Hz FOM (measured in fractional mode at 30 kHz offset with 50 MHz PFD) quantifies the HMC839LP6CETR's efficiency in trading power consumption against phase noise performance. A lower (more negative) FOM indicates superior noise/power optimization - confirming that the HMC839LP6CETR achieves ultra-low in-band phase noise (−112 dBc/Hz) while drawing only ~145 mA total supply current. This makes the HMC839LP6CETR especially valuable in thermally constrained environments like sealed outdoor small cells or densely packed test equipment racks where cooling is limited.

Can the HMC839LP6CETR operate with a 10 MHz reference input, and what impact does that have on phase noise?

Yes, the HMC839LP6CETR supports reference inputs from 10 MHz to 200 MHz (AC-coupled, 1–3.3 V_p-p). However, using a 10 MHz reference degrades synthesizer phase noise by approximately 5 dB near the carrier due to increased multiplication factor (N = f_VCO/f_REF). For example, at 2200 MHz output, N ≈ 220 - amplifying reference noise and increasing close-in phase noise. To maintain optimal −112 dBc/Hz in-band performance, a ≥50 MHz reference (e.g., 100 MHz VCXO) is recommended. The HMC839LP6CETR's wide reference range still enables compatibility with legacy lab equipment or low-cost crystals where ultimate noise is secondary to cost or availability.

What are the critical PCB layout requirements for the HMC839LP6CETR's exposed paddle and ground connections?

The HMC839LP6CETR's exposed ground paddle and all ground pins (e.g., pins 2, 5–6, 8–9, etc.) must be soldered directly to a solid, low-impedance RF ground plane using ≥8 thermal vias (0.3 mm diameter, spaced ≤1 mm apart). Per Hittite Application Note, insufficient grounding causes elevated phase noise (>3 dB degradation), reduced output power, and thermal runaway above 85°C. The paddle must not float or connect only through traces - it requires direct copper fill beneath the package. Layouts ignoring this requirement risk failing FCC/ETSI emissions tests and exhibit unstable VTUNE response. For HMC839LP6CETR evaluation, Rogers 4350 or Arlon 25FR substrates are recommended to preserve 50 Ω impedance integrity.