Analog Devices Inc. HMC838LP6CETR

Overview

HMC838LP6CETR from Analog Devices (formerly Hittite Microwave) is a fully integrated Fractional-N PLL with on-die VCO, operating across three RF bands: 795–945 MHz, 1590–1890 MHz, and 3180–3780 MHz. It delivers ultra-low phase noise (−111 dBc/Hz typ. in-band), <180 fs RMS jitter, 24-bit frequency resolution (3 Hz typ.), and supports exact-frequency mode for precise synthesizer applications in cellular infrastructure and test equipment.

For engineers reviewing the HMC838LP6CETR datasheet, HMC838LP6CETR pinout, HMC838LP6CETR application, or HMC838LP6CETR equivalent, this device is selected for high-data-rate radios requiring fast frequency hopping, low microphonics, and multi-band RF synthesis without external VCO tuning components.

Technical Context

The HMC838LP6CETR implements a delta-sigma modulator architecture enabling fine frequency resolution while suppressing fractional spurs. Its phase detector incorporates cycle-slip prevention (CSP) logic to reduce lock time during large frequency jumps.

It integrates a tri-band VCO with autocalibration, low-noise charge pump (0.02–2.54 mA), precision reference path divider, and fractional-N divider (19-bit integer + 20-bit fractional range). Closed-loop phase noise at 10 kHz offset is −115 dBc/Hz (fractional mode, 50 MHz PFD) at fVCO/2.

Key Specifications

Pinout & Package

40-lead, 6 × 6 mm SMT package (36 mm²) with exposed ground paddle; RoHS-compliant, MSL1, matte Sn finish; thermal resistance Θ_JC = 9 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC838LP6CETR, HMC837LP6CE sacrifices band flexibility for lower cost and smaller footprint, while ADF4371BCPZ trades higher power and layout redesign for extended range and on-chip regulation-neither is pin-compatible, but both serve adjacent frequency-agile RF system roles.

Availability

HMC838LP6CETR is available at Aetrix Electronics and suitable for cellular infrastructure, phased array radar, and communications test equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for HMC838LP6CETR 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 portfolio, specializing in microwave, mmWave, and RF signal chain solutions for defense, communications, and instrumentation.

The HMC838LP6CETR belongs to Hittite's integrated PLL+VCO family, designed specifically for carrier-class wireless infrastructure where spectral purity, multi-band agility, and reliability under thermal stress are critical.

FAQ

What frequency bands does the HMC838LP6CETR support?

The HMC838LP6CETR supports three distinct RF bands: 795–945 MHz (via ÷2 output), 1590–1890 MHz (fundamental VCO output), and 3180–3780 MHz (via ×2 output). These bands align with key cellular standards including LTE Band 5, Band 13, Band 25, Band 41, and 5G NR n41 and n77-enabling single-device coverage across macro and small-cell base station architectures without external frequency multipliers or switches.

Does the HMC838LP6CETR require an external VCO?

No, the HMC838LP6CETR does not require an external VCO-it integrates a tri-band VCO with autocalibration circuitry on-die. The VCO is factory-trimmed and automatically calibrates tuning voltage and prescaler settings per band during power-up. This eliminates external VCO selection components, reduces PCB area, and improves phase noise consistency across temperature and process variation compared to discrete PLL+VCO solutions.

How is the HMC838LP6CETR configured and controlled?

The HMC838LP6CETR uses a 3-wire SPI interface (SEN, SDI, SCK) for register configuration, supporting up to 40 MHz clock rate. All PLL parameters-including N/R dividers, charge pump current, output mode (÷2/fundamental/×2), and calibration enable-are programmable via 32-bit registers. The LD_SDO pin serves dual purpose as lock detect output or serial data output, simplifying system-level monitoring without additional GPIO resources.

What is the significance of the "Exact Frequency Mode" in the HMC838LP6CETR?

Exact Frequency Mode in the HMC838LP6CETR disables the delta-sigma modulator and forces integer-N division while retaining fine frequency resolution through extended N-divider range. This eliminates fractional spurs entirely-critical for applications like spectrum compliance testing, narrowband military comms, and metrology-grade signal sources where spur-free operation within ±1 kHz of target frequency is mandatory.

Can the HMC838LP6CETR operate in doubler mode, and how is it enabled?

Yes, the HMC838LP6CETR supports doubler mode (2fVCO) by shorting pins 28 (RF_N) and 29 (RF_P) together on the PCB. In this configuration, the differential output is internally routed to generate the second harmonic, delivering 3180–3780 MHz output with −25 dBc 2nd harmonic suppression. Output power in doubler mode is −9 to +1 dBm (typ.), requiring external filtering for spurious-sensitive applications.