Analog Devices Inc. HMC704LP4ETR

Overview

HMC704LP4ETR from Analog Devices is a 8 GHz fractional-N phase-locked loop (PLL) IC designed for ultra-low phase noise and minimal spurious content in microwave frequency synthesis. It integrates a low-noise digital phase detector, VCO divider, reference divider, and precision charge pump in SiGe BiCMOS. Key specs include DC–8 GHz RF input range, 100 MHz max PFD rate in fractional mode B, –230 dBc/Hz fractional-mode figure of merit, and 24-bit fractional modulator enabling zero-error exact-frequency generation - critical for digital pre-distortion systems in wireless infrastructure.

For engineers reviewing the HMC704LP4ETR datasheet, HMC704LP4ETR pinout, HMC704LP4ETR application, or HMC704LP4ETR equivalent, this device supports high-speed frequency hopping, low microphonics, and wide loop bandwidths in demanding RF signal generation applications including microwave radios, base stations, and test equipment where spectral purity and timing accuracy are paramount.

Technical Context

The HMC704LP4ETR implements a ΔΣ fractional-N architecture with a 19-bit prescaler supporting both integer and fractional modes across DC–8 GHz RF input. Its dual-mode operation includes Fractional Mode A (≤80 MHz PFD) and Fractional Mode B (≤100 MHz PFD), each with distinct flicker and floor FOM trade-offs.

It features a 4 GHz 19-bit prescaler, internal divide-by-2 for >4 GHz operation, and configurable charge pump current (0.02–2.5 mA in standard mode, up to 6 mA in HiK mode). The PLL interfaces via a 3-wire serial port with read-back capability and supports lock detection, auxiliary serial output, and hardware chip enable for system-level control.

Key Specifications

Pinout & Package

24-lead 4×4 mm lead-frame chip-scale package (LFCSP) with exposed ground paddle; RoHS-compliant, MSL1 rated, matte tin finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC703LP4ETR and ADF4371BCPZ, the HMC704LP4ETR uniquely balances 8 GHz RF bandwidth, 100 MHz PFD rate, and –230 dBc/Hz FOM in a compact 4×4 mm package - making it optimal for external-VCO microwave systems where spectral purity and frequency agility are non-negotiable.

Availability

HMC704LP4ETR is available at Aetrix Electronics and suitable for microwave point-to-point radios, mobile base stations, and wireless test equipment requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for production programs.

Supply support for HMC704LP4ETR 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, Inc. is a global leader in high-performance analog, mixed-signal, and RF ICs, serving communications, industrial, and aerospace markets with precision signal processing solutions.

The HMC704LP4ETR belongs to Analog Devices' high-frequency PLL product line, engineered specifically for microwave and millimeter-wave infrastructure where ultra-low phase noise, fractional resolution, and external-VCO compatibility are essential design requirements.

FAQ

What is the maximum RF input frequency supported by the HMC704LP4ETR?

The HMC704LP4ETR supports an RF input frequency range from DC to 8 GHz. For frequencies above 4 GHz, the internal divide-by-2 must be enabled per datasheet specification [6]. This allows direct interfacing with high-frequency VCOs used in X-band microwave radios and 5G FR2 test equipment without requiring external prescalers.

Does the HMC704LP4ETR include an integrated VCO?

No, the HMC704LP4ETR does not include an integrated VCO. It is a fractional-N PLL IC designed to drive an external VCO via its differential RF input pins (VCOIP and VCOIN). This architecture provides design flexibility to select VCOs optimized for specific frequency bands, tuning range, and phase noise profiles - a key advantage in high-performance microwave systems.

What is the significance of the –230 dBc/Hz fractional-mode figure of merit (FOM) for the HMC704LP4ETR?

The –230 dBc/Hz fractional-mode FOM quantifies the HMC704LP4ETR's phase noise floor performance independent of VCO contribution. A lower (more negative) value indicates superior noise suppression, enabling wider loop bandwidths without degrading integrated jitter - critical for maintaining EVM in high-order QAM systems like 256-QAM WiMAX or 1024-QAM 5G NR.

Can the HMC704LP4ETR operate with a 50 MHz reference input?

Yes, the HMC704LP4ETR supports reference input frequencies from DC to 350 MHz at 3.3 V logic level, including 50 MHz. Its phase detector accepts this frequency in all operating modes, and typical performance plots (e.g., Figures 1–6) are measured using a 50 MHz reference. Spurious performance near integer boundaries is also characterized under this condition.

How is the BIAS pin (Pin 12) used in the HMC704LP4ETR?

The BIAS pin (Pin 12) provides a precision 1.920 V ±20 mV reference voltage for internal analog bias circuits. It must not drive external loads; measurement requires a high-impedance voltmeter (≥10 GΩ) such as the Agilent 34410A - standard 10 MΩ DVMs will load the node and yield erroneous readings below 1.9 V.