Analog Devices Inc. HMC831LP6CE

Overview

HMC831LP6CE from Hittite Microwave Corporation is a fully integrated Fractional-N Phase-Locked Loop (PLL) with on-die VCO, operating from 1815 MHz to 2010 MHz, delivering +4 to +11 dBm RF output power, <180 fs RMS jitter, and –227 dBc/Hz Figure of Merit - designed for high-data-rate wireless infrastructure transceivers requiring ultra-low phase noise and fast frequency hopping.

For engineers reviewing the HMC831LP6CE datasheet, HMC831LP6CE pinout, HMC831LP6CE application, or HMC831LP6CE equivalent, key selection criteria include its 24-bit fractional resolution (3 Hz typ.), cycle-slip prevention architecture, integrated autocalibration for low-voltage VCO tuning, and compatibility with 50 MHz reference inputs in cellular base station and test equipment designs.

Technical Context

The HMC831LP6CE implements a delta-sigma modulator-based fractional-N PLL with an integrated low-noise VCO, precision charge pump (0.02–2.54 mA), and digital phase detector featuring cycle-slip prevention (CSP) for sub-100 µs frequency settling. Its closed-loop integer-mode phase noise reaches –105 dBc/Hz at 1 kHz offset (50 MHz PFD).

It supports three operating modes - fractional feedback (PFD up to 100 MHz), fractional feedforward (PFD up to 80 MHz), and integer (PFD up to 125 MHz) - with programmable 19-bit N-divider (16–524,287) and 14-bit R-divider (1–16,383), all controlled via a 3-wire CMOS serial interface (SEN/SDI/SCK).

Key Specifications

Pinout & Package

40-pin, 6×6 mm surface-mount package (36 mm² footprint) with exposed ground paddle; RoHS-compliant, matte Sn finish, MSL1 rating; 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 HMC831LP6CE, the HMC830LP6CE trades narrowband optimization for wider tuning range, while the ADF4351BCPZ offers broader frequency coverage at the cost of higher jitter, no autocal, and greater layout complexity - making HMC831LP6CE the preferred choice for LTE Band 1/3/25/38/41 infrastructure where phase noise, resolution, and integration are critical.

Availability

HMC831LP6CE is available at Aetrix Electronics and suitable for cellular infrastructure, repeater systems, and communications test equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial deployment.

Supply support for HMC831LP6CE 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

Hittite Microwave Corporation, now part of Analog Devices, specialized in high-frequency RFICs for wireless infrastructure, defense, and test equipment before its 2014 acquisition.

The HMC831LP6CE belongs to Hittite's integrated PLL+VCO product line, engineered specifically for carrier-class wireless infrastructure demanding ultra-low phase noise, fast frequency agility, and production-ready calibration autonomy.

FAQ

What is the primary function of the HMC831LP6CE in RF systems?

The HMC831LP6CE serves as a fully integrated fractional-N PLL synthesizer with on-die VCO, generating highly stable, low-phase-noise local oscillator signals between 1815 MHz and 2010 MHz. It replaces discrete PLL/VCO solutions in cellular infrastructure, enabling compact, high-performance transceivers with minimal external components and no manual VCO tuning - a core capability confirmed by its autocalibration subsystem and 24-bit fractional divider.

Does the HMC831LP6CE require an external loop filter?

Yes, the HMC831LP6CE requires an external passive loop filter connected to its CP (Pin 4) output. The charge pump drives this filter to generate the VTUNE (Pin 23) control voltage for the integrated VCO. Filter component values depend on desired loop bandwidth and stability; Hittite recommends contacting factory support for validated designs - a requirement explicitly stated in the datasheet for achieving specified phase noise and settling performance.

What is the significance of the "Exact Frequency Mode" feature in the HMC831LP6CE?

The Exact Frequency Mode in the HMC831LP6CE enables deterministic, repeatable frequency synthesis without fractional spurs or dither-induced uncertainty - critical for applications like DDS replacement and metrology-grade test equipment. This mode leverages the device's 24-bit fractional divider and delta-sigma modulator to achieve 3 Hz typical step resolution while maintaining ultra-low in-band phase noise, as verified in the datasheet's typical closed-loop fractional phase noise plots.

How does the HMC831LP6CE handle temperature and process variation across its operating range?

The HMC831LP6CE incorporates an integrated autocalibration subsystem that dynamically adjusts VCO tuning parameters during power-up and periodically in operation to compensate for temperature drift and process variation. This ensures consistent 1815–2010 MHz coverage and linear VTUNE response from –40°C to +85°C, as demonstrated in the "Typical VCO Tuning Voltage After Calibration" and "VCO Sensitivity vs. Cap @ Fo Voltage" plots in the datasheet.

Can the HMC831LP6CE operate with a 10 MHz reference input?

Yes, the HMC831LP6CE supports reference inputs from 10 MHz to 200 MHz, as specified in the "REF Input Characteristics" table. However, using a 10 MHz reference degrades synthesizer phase noise by approximately 5 dB compared to higher-frequency references (e.g., 50 MHz), due to increased multiplication ratio - a trade-off documented in the datasheet's note on reference frequency impact.