Analog Devices Inc. HMC701LP6CETR

Overview

HMC701LP6CETR from Analog Devices (formerly Hittite Microwave) is a SiGe BiCMOS fractional-N phase-locked loop synthesizer with 8 GHz RF input capability, 16-bit N-divider, and 24-bit delta-sigma modulator. It delivers ultra-low in-band phase noise (−103 dBc/Hz @ 20 kHz offset, fractional mode, 6 GHz VCO, 50 MHz PFD) and supports fast frequency hopping via cycle slip prevention for radar and wireless test equipment.

For engineers reviewing the HMC701LP6CETR datasheet, HMC701LP6CETR pinout, HMC701LP6CETR application, or HMC701LP6CETR equivalent, key selection criteria include its 8 GHz max RF input frequency, 3 Hz typical frequency step resolution, integrated 14-bit reference divider, low fractional spurs (−90 dBc typ), and support for both sine and square-wave reference inputs - critical for FMCW sensor and phased-array system design.

Technical Context

The HMC701LP6CETR implements a dual-path architecture: a low-noise analog phase-frequency detector (PFD) with programmable gain and a precision charge pump (125 µA–4 mA output range), paired with a 24-bit delta-sigma modulator enabling 3 Hz fine frequency resolution. Its RF path includes a differential 8 GHz prescaler with AC-coupled VCOIN/VCOIP inputs and ESD protection.

The reference path provides two optimized inputs - XSIN (50 Ω sinusoidal, −159 dBc/Hz noise floor) and XREFP (square-wave) - selectable via register control. It features a 14-bit R-divider (1–16,383), auto-refdiv logic, and auxiliary clock generation via GPO pins for synchronized sweep triggering and lock detection.

Key Specifications

Pinout & Package

40-pin, 6 mm × 6 mm LFCSP package (36 mm² footprint) with exposed thermal pad; RoHS-compliant, reflow-compatible (260°C peak, 40 sec).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADF4371BCPZ and LMS8001TR, the HMC701LP6CETR offers superior phase noise at 6–8 GHz, explicit support for external high-performance VCOs, and finer frequency resolution (3 Hz vs 10 Hz), making it the preferred choice for radar and test equipment where spectral purity and external component control are critical.

Availability

HMC701LP6CETR is available at Aetrix Electronics and suitable for automotive radar, 5G base station test equipment, and phased-array communications systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for HMC701LP6CETR 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 lines, specializing in precision analog, RF, and microwave ICs for defense, communications, and instrumentation.

The HMC701LP6CETR belongs to the Hittite PLL family designed specifically for demanding microwave frequency synthesis applications - emphasizing ultra-low phase noise, fast settling, and flexible reference/VCO interfacing in radar, EW, and wireless infrastructure.

FAQ

What reference input type does HMC701LP6CETR support, and how do I select between them?

HMC701LP6CETR supports two independent reference inputs: XSIN (sinusoidal, 20–220 MHz, 50 Ω) and XREFP (square-wave, 20–200 MHz). Selection is controlled via registers rfp_buf_sin_sel and rfp_buf_sq_en. For lowest phase noise, use XSIN with AC coupling and enable its buffer; XREFP is default on power-up but must be disabled if XSIN is active to prevent noise coupling. The HMC701LP6CETR datasheet specifies that only one path should be enabled per design.

Does HMC701LP6CETR integrate a VCO, or is it designed for external VCO use?

HMC701LP6CETR does not integrate a VCO. It is explicitly designed as a fractional-N PLL core for use with external VCOs, featuring differential RF inputs (VCOIN/VCOIP) rated to 8 GHz (fractional) and 9 GHz (integer). This architecture allows system designers to optimize VCO performance independently - critical for applications like FMCW radar where VCO phase noise and tuning linearity directly impact range resolution and velocity accuracy. The HMC701LP6CETR provides the precise N-divider, PFD, and charge pump needed to lock and steer those external oscillators.

How does Cycle Slip Prevention (CSP) improve settling time in HMC701LP6CETR?

HMC701LP6CETR implements Cycle Slip Prevention by dynamically adjusting the phase-frequency detector (PFD) gain during frequency transitions, reducing overshoot and minimizing missed cycles in the feedback loop. This feature cuts frequency hop time by approximately 50% compared to conventional PFDs - verified in measured data showing <10 µs settling from 5200 MHz to 3950 MHz with CSP enabled. The HMC701LP6CETR's CSP is register-configurable and particularly effective in radar chirp and agile communication systems where rapid, deterministic locking is mandatory.

What are the power supply requirements for HMC701LP6CETR, and why are multiple rails used?

HMC701LP6CETR requires three distinct supply domains: +3.3 V for RF/analog sections (VCCHF, RVDD, DVDD), +3.3 V for digital I/O (DVDDIO), and +5 V for charge pump and op-amps (VPPCP, VCCOA, VDDPD). This separation isolates noise-sensitive analog paths (e.g., CP output, PFD) from digital switching noise, directly contributing to its −103 dBc/Hz phase noise performance. The HMC701LP6CETR datasheet specifies strict decoupling requirements per rail - including 100 nF ceramic caps near each supply pin - to maintain this isolation and prevent spurious degradation.

Can HMC701LP6CETR generate frequency sweeps autonomously, and how is it configured?

Yes, HMC701LP6CETR includes an integrated linear sweeper subsystem that generates autonomous frequency chirps without host processor intervention. Sweep parameters - start/stop frequency, dwell time, polarity, and trigger source (internal or external via GPO3) - are programmed via registers REG 14h–REG 1Ah. The HMC701LP6CETR supports wide sweep ranges (e.g., 3.9–6.1 GHz) with microsecond-level timing control, making it ideal for FMCW radar and swept-spectrum test applications where deterministic, low-jitter chirps are required.