Analog Devices Inc. HMC704LP4E

Overview

HMC704LP4E from Analog Devices is an 8 GHz fractional-N phase-locked loop (PLL) IC with integrated prescaler, charge pump, and digital phase detector. It supports RF input up to 8 GHz, operates with 100 MHz phase detector rate in fractional mode B, achieves -230 dBc/Hz fractional-mode figure of merit, and delivers ultra-low spurious performance for microwave frequency synthesis in wireless infrastructure.

For engineers reviewing the HMC704LP4E datasheet, HMC704LP4E pinout, HMC704LP4E application, or HMC704LP4E equivalent, this device is selected for high-performance RF synthesizer designs requiring exact fractional frequency generation, fast frequency hopping, low microphonics, and compatibility with external VCOs in point-to-point radio and base station transceivers.

Technical Context

The HMC704LP4E implements a SiGe BiCMOS-based fractional-N architecture with a 24-bit fractional modulator enabling zero-error frequency synthesis-critical for digital pre-distortion systems. Its dual-mode operation supports integer and fractional modes with selectable prescaler configurations (8 GHz/4 GHz paths), and its high-K charge pump enables wide loop bandwidths while maintaining low in-band phase noise.

It integrates a 19-bit RF divider (even-only for 8 GHz paths), reference divider (14-bit), and precision-controlled charge pump with 20 µA current steps. The serial interface provides read-back capability and supports multiple protocol formats, while lock detection and auxiliary serial output enable system-level monitoring and synchronization.

Key Specifications

Pinout & Package

24-lead, 4 mm × 4 mm lead-frame chip-scale package (LFCSP) with exposed thermal 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 HMC704LP4E, the HMC703LP4E trades 8 GHz capability and superior FOM for lower cost and simpler layout, while the ADF4371 replaces external VCO dependency with on-die VCO-offering faster time-to-market but reduced phase noise control in high-frequency bands.

Availability

HMC704LP4E is available at Aetrix Electronics and suitable for microwave point-to-point radios, mobile base station transceivers, and wireless test equipment requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for HMC704LP4E 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 timing and signal processing solutions.

The HMC704LP4E belongs to Analog Devices' Hittite Microwave PLL product line, engineered specifically for ultra-low phase noise and spurious-free microwave frequency synthesis in wireless infrastructure and defense systems.

FAQ

What is the maximum RF input frequency supported by the HMC704LP4E?

The HMC704LP4E supports an RF input frequency range from DC to 8 GHz. This is verified in Table 1 under "RF Input Frequency Range" and confirmed by the "8 GHz Fractional-N PLL" designation in the product title. Operation above 4 GHz requires enabling the internal divide-by-2 function, as noted in footnote [6] of the datasheet. The device maintains specified phase noise and spurious performance across this full band when used with appropriate external VCO and loop filter design.

Does the HMC704LP4E include an integrated VCO?

No, the HMC704LP4E does not include an integrated VCO. It is a PLL core IC designed to drive an external VCO via its differential RF inputs (VCOIP and VCOIN). The functional diagram and "External VCO" section on page 5-13 explicitly confirm this architecture. The device provides a high-performance charge pump output (pin 16) and supports tuning voltages up to 5.2 V, enabling direct interfacing with discrete or module-based VCOs across microwave bands.

What is the significance of the -266 dBc/Hz flicker figure of merit for the HMC704LP4E?

The -266 dBc/Hz flicker figure of merit quantifies the HMC704LP4E's exceptional close-in phase noise performance-critical for applications sensitive to 1/f noise such as radar Doppler processing and high-order QAM modulation. This value is measured under specified conditions (high charge-pump current, +12 dBm 100 MHz reference) and directly enables wider loop bandwidths without degrading EVM. It reflects the SiGe BiCMOS process and low-noise circuit design optimized for microwave synthesizers.

Can the HMC704LP4E operate with a 50 MHz reference input?

Yes, the HMC704LP4E supports reference input frequencies from DC to 350 MHz at 3.3 V, including 50 MHz. Table 1 specifies "Ref Input Frequency Range (3.3 V)" as DC to 350 MHz, and multiple performance plots (e.g., Figures 5–6) use 50 MHz as the reference condition. The device's phase detector operates reliably at 50 MHz in both integer and fractional modes, and spurious measurements in Figure 15 explicitly cite "50 MHz reference" as the test condition.

What package type and thermal characteristics does the HMC704LP4E use?

The HMC704LP4E uses a 24-lead 4 mm × 4 mm LFCSP (lead-frame chip-scale package) with exposed thermal paddle. Table 4 confirms "Package Body Material: RoHS-compliant Low Stress Injection Molded Plastic" and "Thermal Resistance (Jxn to Gnd Paddle): 25 °C/W". The exposed paddle must be soldered to PCB RF ground per note [8], and the MSL1 rating permits peak reflow at 260 °C for 40 seconds-enabling standard lead-free assembly processes.