Analog Devices Inc. HMC820LP6CE

Overview

HMC820LP6CE from Analog Devices (formerly Hittite Microwave) is a fully functioned Fractional-N Phase-Locked Loop (PLL) with integrated voltage-controlled oscillator (VCO), operating across three RF bands: 1095–1275 MHz, 2190–2550 MHz, and 4380–5100 MHz. It delivers ultra-low phase noise (−105 dBc/Hz in-band typ.), <180 fs RMS jitter, 24-bit frequency resolution (3 Hz typ.), and supports exact frequency mode for precise synthesis in cellular infrastructure and test equipment.

For engineers reviewing the HMC820LP6CE datasheet, HMC820LP6CE pinout, HMC820LP6CE application, or HMC820LP6CE equivalent, key selection criteria include tri-band VCO coverage, fractional-N architecture with cycle-slip prevention, integrated autocalibration, low-noise charge pump (0.02–2.54 mA), and 40-lead 6×6 mm SMT package compatibility with high-density RF layouts.

Technical Context

The HMC820LP6CE implements a delta-sigma modulator-based fractional-N PLL with an integrated tri-band VCO and autocalibration subsystem for low-voltage tuning. Its phase detector features cycle-slip prevention (CSP) to enable fast frequency hopping, while the precision charge pump and low-noise reference path divider support wide loop bandwidths without compromising microphonic sensitivity.

It operates with multiple output configurations: fundamental (f_VCO), divide-by-2 (f_VCO/2), and doubler (2f_VCO), each with distinct RF output power levels (e.g., +10 dBm typ. at f_VCO/2, +6.5 dBm typ. at f_VCO, −4 dBm typ. at 2f_VCO) and harmonic suppression (e.g., −20 dBc 2nd harmonic at f_VCO/2 mode).

Key Specifications

Pinout & Package

Package: 40-lead, 6×6 mm LFCSP (lead-frame chip-scale package) with exposed ground paddle; RoHS-compliant, MSL1, thermal resistance 20 °C/W (junction-to-paddle).

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC820LP6CE, HMC821LP6CE offers identical form-factor and interface but narrower band coverage, while ADF4371BCPZ provides broader frequency range and enhanced digital control at the cost of higher current draw and larger package-making HMC820LP6CE optimal for compact, tri-band 4G/5G infrastructure designs.

Availability

HMC820LP6CE 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 traceable sourcing from authorized channels.

Supply support for HMC820LP6CE 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 integrates its high-frequency RF portfolio into precision analog and RF signal chain solutions.

The HMC820LP6CE belongs to the Hittite PLLs with Integrated VCOs product line, designed specifically for high-performance wireless infrastructure where ultra-low phase noise, fast frequency agility, and multi-band integration reduce system complexity and bill-of-materials cost.

FAQ

What RF output bands does the HMC820LP6CE support, and how are they selected?

The HMC820LP6CE supports three RF output bands: 1095–1275 MHz (f_VCO/2), 2190–2550 MHz (f_VCO), and 4380–5100 MHz (2f_VCO). Band selection is determined by internal VCO configuration and output divider settings programmed via the 4-wire SPI interface. No external switching components are required-the device automatically selects the appropriate VCO core and tuning bank during calibration. The HMC820LP6CE's autocalibration subsystem ensures stable operation across all bands under varying temperature and supply conditions.

Does the HMC820LP6CE require external loop filtering, and what are the key design constraints?

Yes, the HMC820LP6CE requires an external passive loop filter between the CP pin and VTUNE. Key constraints include matching the charge pump current (programmable 0.02–2.54 mA) to filter impedance, limiting loop bandwidth to ≤80 kHz for integer mode stability (per datasheet Fig. 7-5), and using low-ESR capacitors to avoid peaking. The HMC820LP6CE's cycle-slip prevention allows wider bandwidths than conventional PLLs, but filter component tolerances must be ≤1% to maintain phase margin >45° across temperature. Reference design values are available in the Hittite "PLLs with Integrated VCOs Operating Guide".

How does the HMC820LP6CE achieve ultra-low phase noise, and what contributes most to its −227 dBc/Hz figure of merit?

The HMC820LP6CE achieves ultra-low phase noise through a combination of ultra-low-noise phase detector (−153 dBc/Hz at 100 kHz offset), precision-controlled charge pump, integrated low-noise VCO with tri-band optimization, and advanced delta-sigma fractional-N modulation that suppresses quantization spurs. Its −227 dBc/Hz figure of merit (FOM) reflects the normalized trade-off between phase noise, offset frequency, and power-driven primarily by the VCO's open-loop phase noise floor (−147 dBc/Hz at 1 MHz offset for f_VCO/2) and the PLL's ability to suppress reference noise. The HMC820LP6CE's FOM is measured at 30 kHz offset with 50 MHz PFD, confirming best-in-class efficiency for its power class.

Can the HMC820LP6CE operate in exact frequency mode, and how does it simplify system firmware?

Yes, the HMC820LP6CE supports Exact Frequency Mode, allowing direct entry of the desired output frequency (e.g., 2140.5 MHz) without manual calculation of N, R, and fractional word values. Internally, the device computes optimal divider ratios and modulator coefficients, reducing firmware overhead and eliminating floating-point math errors. This mode is especially valuable in dynamic spectrum access and carrier aggregation applications where real-time frequency reconfiguration is required. The HMC820LP6CE retains full register-level control for advanced users while enabling plug-and-play frequency programming via a single SPI write.

What is the recommended PCB layout practice for the HMC820LP6CE's exposed ground paddle and RF outputs?

The HMC820LP6CE's exposed ground paddle must be soldered to a solid, low-inductance RF ground plane using ≥9 thermal vias (0.3 mm diameter, spaced ≤1 mm apart) connecting to inner and bottom ground layers. RF_N and RF_P pins require controlled 50 Ω differential microstrip routing with tight coupling (≤0.2 mm gap), no stubs, and immediate grounding adjacent to the package. All N/C pins (e.g., pins 2, 5–6) must be externally grounded with short traces to minimize parasitic resonance. The HMC820LP6CE evaluation board (PCB #127825/128157) provides validated land patterns and stack-up guidance for Rogers 4350 or Arlon 25FR laminates.