Analog Devices Inc. HMC834LP6GE

Overview

HMC834LP6GE from Analog Devices (formerly Hittite Microwave) is a fractional-N phase-locked loop with integrated VCO, operating across four RF bands: 45–1050 MHz, 1400–2100 MHz, 2800–4200 MHz, and 5600–8400 MHz. It delivers ultra-low phase noise (−110 dBc/Hz in-band typ.), <180 fs RMS jitter, and 24-bit frequency resolution (3 Hz typ.), serving as a low-spur local oscillator in cellular infrastructure and test equipment.

For engineers reviewing the HMC834LP6GE datasheet, HMC834LP6GE pinout, HMC834LP6GE application, or HMC834LP6GE equivalent, key selection criteria include its 100 MHz max phase detector rate, Exact Frequency Mode for zero-Hz error synthesis, integrated VCO output divider (1/2/4/6…/62), and 40-lead 6×6 mm QFN package with exposed paddle.

Technical Context

The HMC834LP6GE implements a delta-sigma modulator-based fractional-N architecture with an integrated fundamental VCO (2800–4200 MHz), on-chip doubler, and programmable RF output divider enabling wideband coverage. Its phase detector supports up to 100 MHz in Fractional Mode B, requiring minimum N values to maintain stability.

It features dual supply domains: 5 V for VCO core, charge pump, and dividers; 3.3 V for digital logic, prescaler, and analog biasing. The device includes built-in digital self-test, output mute, and RF power control (0–6 dB in ~2 dB steps), with lock detect available on LD_SDO pin.

Key Specifications

Pinout & Package

40-lead, 6×6 mm QFN package with exposed ground paddle (RoHS-compliant, MSL1, matte Sn finish). Package marking: "H834" + 4-digit lot code.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC834LP6GE, HMC832LP6GE offers reduced bandwidth and phase noise performance but lower cost, while ADF4355-3BCPZ provides smaller footprint and extended low-frequency reach but lacks the HMC834LP6GE's dedicated tunable-reference spur mitigation and Exact Frequency Mode implementation.

Availability

HMC834LP6GE is available at Aetrix Electronics and suitable for cellular infrastructure, phased array radar, and high-speed test equipment requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for HMC834LP6GE 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-frequency RF IC portfolio, including PLLs, VCOs, and microwave front-end components.

The HMC834LP6GE belongs to Hittite's integrated PLL+VCO product line, designed specifically for demanding wireless infrastructure and instrumentation applications requiring ultra-low phase noise, wide tuning range, and high spectral purity.

FAQ

What is the maximum reference input frequency supported by the HMC834LP6GE?

The HMC834LP6GE supports a maximum reference input frequency of 350 MHz. This AC-coupled, 50 Ω input accepts sine or square wave signals with 1–3.3 V_p-p amplitude and is compatible with standard crystal oscillators, clock generators, and frequency synthesizers. Operation above 100 MHz requires careful attention to signal integrity and termination per the Hittite PLL Operating Guide.

Does the HMC834LP6GE support both integer-N and fractional-N modes?

Yes, the HMC834LP6GE supports both integer-N and fractional-N PLL modes. Integer mode enables highest phase noise performance and lowest spurs, while fractional mode provides fine frequency resolution (3 Hz typ.) and flexible channel spacing. The device also features Exact Frequency Mode, which eliminates residual fractional spur accumulation for fixed-frequency outputs.

How is the RF output configured for single-ended versus differential operation on the HMC834LP6GE?

The HMC834LP6GE provides a single RF_N pin that supports both configurations: in differential mode, RF_N is used with an external 180° hybrid or balun; in single-ended mode, RF_N drives a 50 Ω load directly with internal broadband matching. No external matching network is required in either case, and output power is adjustable from 0 to 6 dB in ~2 dB steps via register control.

What thermal management considerations apply to the HMC834LP6GE package?

The HMC834LP6GE uses a 40-lead 6×6 mm QFN with exposed ground paddle and has a junction-to-paddle thermal resistance of 20 °C/W. For reliable operation at full power, the paddle must be soldered to a solid PCB ground plane using ≥9 thermal vias (0.3 mm diameter, 0.8 mm pitch). Peak reflow temperature is 260 °C for 40 seconds, and operating junction temperature must remain ≤125 °C.

Can the HMC834LP6GE generate frequencies below 100 MHz, and how does it achieve low spurs at those frequencies?

Yes, the HMC834LP6GE generates frequencies as low as 45 MHz using its integrated VCO divider (e.g., divide-by-62 at 2800 MHz → 45.16 MHz). Low spurs at these frequencies are achieved by using a tunable reference (e.g., 47.5 MHz instead of fixed 50 MHz), which shifts integer boundary spurs away from critical offsets - a technique validated in application notes and Figure 21 of the datasheet.