Analog Devices Inc. HMC835LP6GETR

Overview

HMC835LP6GETR from Analog Devices (formerly Hittite Microwave) is a fractional-N phase-locked loop with integrated VCO, operating from 33 MHz to 4100 MHz. It delivers low phase noise (−110 dBc/Hz @2 GHz), <94 fs integrated RMS jitter (1 kHz–100 MHz), and supports exact-frequency mode with zero-Hz fractional error-enabling precise local oscillator synthesis in cellular infrastructure and MIMO radio systems.

For engineers reviewing the HMC835LP6GETR datasheet, HMC835LP6GETR pinout, HMC835LP6GETR application, or HMC835LP6GETR equivalent, key selection criteria include its dual differential RF outputs, programmable output phase synchronization, external LO input capability, and support for cascaded PLL architectures in phased-array and communication test equipment.

Technical Context

The HMC835LP6GETR integrates a fundamental VCO (2050–4100 MHz) with a programmable divider chain (÷1, ÷2, ÷4, ..., ÷62), enabling full-band coverage down to 33 MHz. Its delta-sigma modulator and phase detector operate up to 100 MHz, permitting wide loop bandwidths and fast frequency settling.

It features two independent charge pump outputs for separate loop filters-one optimized for the internal VCO and another for external VCO locking-plus configurable RF output mute and phase-synchronous frequency switching. The AutoCal calibration engine ensures stable tuning voltage across −40°C to +85°C without manual recalibration.

Key Specifications

Pinout & Package

40-lead, 6 mm × 6 mm LFCSP package (36 mm² footprint) with exposed thermal pad. RoHS-compliant, lead-free, and designed for high-frequency signal integrity and thermal dissipation in dense RF layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADF4371BCPZ and LMS8001TR, the HMC835LP6GETR offers superior size efficiency (6×6 mm), proven <94 fs jitter at 5G FR1 frequencies, and seamless AutoCal operation-making it the preferred choice for thermally constrained, multi-unit coherent LO systems in cellular infrastructure.

Availability

HMC835LP6GETR is available at Aetrix Electronics and suitable for cellular infrastructure, MIMO radio architectures, and communication test equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for HMC835LP6GETR 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 continues to manufacture and support its high-performance RF portfolio, including microwave PLLs, VCOs, and integrated transceivers.

The HMC835LP6GETR belongs to Analog Devices' legacy Hittite PLL/VCO product line, engineered specifically for demanding wireless infrastructure applications requiring wideband agility, ultra-low jitter, and deterministic phase control.

FAQ

What is the minimum and maximum output frequency supported by the HMC835LP6GETR?

The HMC835LP6GETR supports an output frequency range from 33 MHz to 4100 MHz. This is achieved using its integrated VCO (2050–4100 MHz fundamental) combined with a programmable divider (÷1, ÷2, ÷4, ..., ÷62). At ÷62, the lowest output is ~33 MHz (2050 MHz ÷ 62); at ÷1, the highest is 4100 MHz. All frequencies within this span are achievable with integer or fractional-N synthesis.

Does the HMC835LP6GETR support phase synchronization across multiple devices?

Yes, the HMC835LP6GETR supports deterministic phase synchronization across multiple units via its programmable RF output phase feature. Using a 24-bit seed register (Reg 1Ah), users can adjust output phase in fine increments-enabling precise alignment for beamforming and MIMO applications. Synchronization requires a common reference clock and coordinated register writes, as validated in Figures 26–28 of the datasheet.

What is the purpose of the AutoCal function in the HMC835LP6GETR?

The AutoCal function in the HMC835LP6GETR automatically recalibrates the VCO tuning characteristics during each frequency change, ensuring stable VTUNE voltage across temperature (−40°C to +85°C) without external intervention. As shown in Figure 8, calibration executed at one temperature remains valid across the full operating range-eliminating drift-induced unlock events and simplifying system-level thermal design.

Can the HMC835LP6GETR lock to an external VCO instead of using its internal VCO?

Yes, the HMC835LP6GETR includes an external LO input path and two independent charge pump outputs, allowing it to lock to an external VCO while maintaining separate loop filter optimization. This enables cascaded PLL architectures-for example, using a low-noise external VCO for final-stage upconversion while the HMC835LP6GETR handles coarse frequency planning and division. The external LO path is explicitly documented in the General Description section.

What are the power supply requirements for the HMC835LP6GETR?

The HMC835LP6GETR requires dual supplies: +5 V for VCO core, charge pump, and LO buffers (VCC1, VCC2, VDDCP); and +3.3 V for digital logic, PLL circuitry, and interface (AVDD, DVDD, VCCHF, etc.). Typical total current draw is 118–168 mA on +5 V (depending on output configuration) and 48 mA on +3.3 V. Power-down current drops to 1 µA when crystal is off, as specified in the Electrical Specifications table.