company blog about ADI HMC3716LP4ETR 10MHz To 1300MHz HBT Digital Phase Frequency Detector

Shenzhen Mingjiada Electronics Co., Ltd. supplies the ADI HMC3716LP4ETR 10MHz to 1300MHz HBT digital phase-frequency detector.

The ADI HMC3716LP4ETR is a high-performance digital phase-frequency detector (PFD) designed using heterojunction bipolar transistor (HBT) technology, operating across a wide frequency range from 10MHz to 1300MHz. Tailored specifically for low-phase-noise frequency synthesiser applications, it is widely used in high-end RF systems such as point-to-point radio, satellite communications, military equipment and clock generation, thanks to its outstanding RF performance, compact package design and extensive feature set. It provides precise phase and frequency detection capabilities for the system and is one of the core components in a phase-locked loop (PLL) architecture.

I. Overview of the HMC3716LP4ETR Device

Manufactured using advanced HBT technology, the HMC3716LP4ETR combines high-frequency operation with ultra-low phase noise characteristics. It accurately detects the phase and frequency differences between two input signals (the reference signal REF and the voltage-controlled oscillator signal VCO), converting the detection results into a digital pulse signal output. This provides precise control reference for subsequent loop filtering, charge pump operation and VCO regulation. This device overcomes the performance limitations of traditional phase-detector (PFD) circuits in the high-frequency range, maintaining stable detection accuracy across the full operating frequency range of 10 MHz to 1300 MHz. It also offers advantages such as high integration, reasonable power consumption and strong immunity to interference, significantly simplifying the design complexity of RF systems whilst enhancing overall system stability and reliability.

As one of the core components in ADI’s RF product portfolio, the HMC3716LP4ETR works in conjunction with devices such as differential loop amplifiers and charge pumps to build high-performance phase-locked loop systems, enabling precise locking of the VCO output frequency. It is widely suited to low-phase-noise, fast-switching RF applications and meets the stringent requirements for frequency synthesis accuracy in high-end communications and defence electronics sectors.

II. Key Performance Parameters of the HMC3716LP4ETR

The performance advantages of the HMC3716LP4ETR are primarily reflected in core parameters such as wide-band adaptability, low phase noise and high sensitivity. The specific key parameters are as follows, providing an accurate reference for system design:

- Operating frequency range: 10 MHz to 1300 MHz. Input signals support square waves (minimum frequency) and sine/square waves (maximum frequency), accommodating various RF signal types and covering application requirements across the mid-to-high frequency bands.

- Phase noise performance: Single-sideband (SSB) phase noise floor as low as -153 dBc/Hz (10 kHz offset, 100 MHz input frequency). This is a core advantage for low-phase-noise synthesiser design, effectively reducing system frequency jitter and enhancing signal purity.

- Input characteristics: The input power range is -10 dBm to +5 dBm. With improved input sensitivity, it can accurately detect weak input signals and is suitable for reference signals and VCO feedback signals of varying strengths.

- Output Characteristics: An integrated output resistor eliminates the need for external resistors, simplifying circuit design; the output voltage swing is 2Vp-p (high-impedance load/operational amplifier drive), with a phase-frequency detector gain of 0.32V/rad, ensuring a stable output signal that facilitates subsequent loop processing.

- Logic and Control Characteristics: Supports CMOS/TTL logic levels, with a logic low range of 0.0V to 1.8V and a logic high range of 1.1V to 5.0V; features lock detection (LD) and inversion (INV) functions, allowing flexible adaptation to system layout and control requirements.

- Environment and Packaging: Utilises a 24-pin 4mm × 4mm leadless QFN surface-mount package (with exposed ground pad), effectively improving RF performance and thermal dissipation; the operating temperature range is -40°C to 85°C, meeting the wide-temperature requirements of industrial and military applications, and complies with RoHS standards.

- Other Parameters: The lock detection output requires an external 1kΩ pull-up resistor and an RC filter; a high level after filtering indicates a locked state, whilst a low level indicates an unlocked state; when the invert pin is at logic high, the REF and VCO input signals can be swapped, facilitating the correction of layout issues.

III. Core Functions and Operating Principles of the HMC3716LP4ETR

Core Functions

The core function of the HMC3716LP4ETR is to detect the phase and frequency differences between the two input signals (REF and VCO), whilst providing lock detection and phase inversion control functions. The specific functions are as follows:

- Phase and Frequency Detection: By comparing the rising edges of the REF and VCO input signals, the device determines their frequency and phase relationship. When the VCO frequency is higher than the REF frequency, the ND pin outputs an active pulse; when the VCO frequency is lower than the REF frequency, the NU pin outputs an active pulse. The average voltage of the active pulse ranges between 3 and 5 V, whilst the output remains constant at approximately 5 V in the inactive state.

- Lock Detection: The LD pin provides an open-collector pulse output, requiring an external RC filter and a 1kΩ pull-up resistor. The filtered output voltage can be used to determine the system’s lock status—a high level indicates that the REF and VCO signals are locked, whilst a low level indicates they are not locked, facilitating system status monitoring and control.

- Inversion Function: The INV pin controls the swapping of input signals. The device operates normally at a logic low level; at a logic high level, the REF and VCO input signals are swapped, thereby swapping the responses of the NU and ND pins. This provides a flexible solution to signal swapping requirements arising from system layout.

Operating Principle

As the core detection device in a phase-locked loop (PLL) system, the HMC3716LP4ETR operates in close conjunction with the PLL system. The overall process is as follows:

1. The reference signal (REF) and the feedback signal from the voltage-controlled oscillator (VCO) are input to the device’s REF and VCO pins respectively. The internal HBT circuit precisely samples and compares the rising edges of both signals;

2. If a frequency difference exists between the two signals, the device outputs a corresponding digital pulse signal via the NU/ND pins to control the charging and discharging states of the subsequent charge pump, thereby regulating the output voltage of the loop filter;

3. The loop filter integrates the pulse signals from the NU/ND pins and converts them into a DC control voltage, which is applied to the VCO to adjust its output frequency, causing the VCO frequency to gradually converge towards the REF frequency;

4. When the VCO frequency matches the REF frequency and the phase difference stabilises, the device enters a locked state, with the LD pin outputting a high level, and the system maintains stable operation; should any frequency or phase deviation occur, the device restarts the detection and adjustment process to maintain system lock;

5. By combining high operating frequency with an ultra-low phase noise floor, this device enables synthesiser designs featuring wide loop bandwidth and low division ratios, thereby achieving the dual advantages of rapid system switching and extremely low phase noise. When used in conjunction with a differential loop amplifier, it generates a stable VCO phase-locked control voltage.

IV. HMC3716LP4ETR Package and Pin Description

Package Specifications

The HMC3716LP4ETR is housed in a 24-pin 4mm × 4mm QFN (Quad Flat No-lead) package, featuring an exposed ground pad (EP). This design not only significantly reduces the device’s footprint, facilitating high-density PCB layout, but also effectively reduces radio frequency interference and improves thermal dissipation, ensuring the device’s stability in high-frequency, high-power operating scenarios—the exposed ground pad rapidly dissipates heat generated during operation, preventing performance degradation or device damage caused by overheating.

Key Pin Functions (Core Pins)

Among the device’s 24 pins, the core functional pins primarily include input, output, control and power pins. The key pin functions are as follows (please refer to the official data sheet for detailed pin definitions):

- REF/IN+, VCO/IN-: Reference signal and VCO feedback signal input pins, supporting signal inputs from 10 MHz to 1300 MHz; note that impedance matching is required to ensure signal integrity;

- NU, ND: Phase-frequency detection output pins; these provide active pulse outputs when the VCO frequency is below or above the REF frequency, respectively. They incorporate output resistors and can be directly connected to subsequent charge pumps or operational amplifiers;

- LD: Lock detection output pin; open-collector output requiring an external 1kΩ pull-up resistor and RC filter; used to output the system lock status signal;

- INV: Invert control pin; controlled by CMOS/TTL logic levels; used to swap the REF and VCO input signals;

- VCC, GND: Power supply and ground pins; the exposed ground pad must be properly grounded to ensure heat dissipation and RF performance;

- NC: No-connect pin; no connection required; care must be taken during layout to maintain sufficient spacing from other pins to avoid interference.

V. HMC3716LP4ETR Application Scenarios

With its wide bandwidth, low phase noise, high sensitivity and extensive control functions, the HMC3716LP4ETR is suitable for a wide range of high-end RF applications. It is particularly well-suited to systems with stringent requirements for frequency accuracy and signal purity. The main application areas are as follows:

- Point-to-point radio systems: Serving as a core phase-frequency detection component, it enables the construction of high-performance phase-locked loop (PLL) frequency synthesizers, ensuring the frequency stability and transmission quality of radio signals, and meeting the requirements of point-to-point communication in the mid-to-high frequency bands.

- Satellite communication systems: Used in frequency synthesis modules for satellite receivers and transmitters, its ultra-low phase noise characteristics enhance the anti-interference capability and signal demodulation accuracy of satellite communications, meeting the high-frequency and high-precision requirements of satellite communications.

- Military applications: Suitable for RF systems in defence electronic equipment, such as radars and electronic countermeasure devices. The wide operating temperature range and high reliability meet the stringent requirements of military environments, providing stable frequency control capabilities for such equipment.

- SONET Clock Generation: Used in clock generation modules for Synchronous Optical Networks (SONET). It precisely detects the phase and frequency of clock signals, ensuring the synchronisation and stability of network clocks and guaranteeing the accuracy of data transmission.

- Other High-End RF Systems: Can also be applied to test and measurement instruments, high-frequency signal generators, RF transceivers and other equipment, providing precise phase and frequency detection and control for various devices, thereby enhancing their overall performance.

VI. Advantages of the HMC3716LP4ETR Device

- Wide-band adaptability: Stable operation across the full 10 MHz to 1300 MHz frequency range, covering mainstream applications in the mid-to-high frequency bands, and accommodating different frequency requirements without the need to replace the device;

- Ultra-low phase noise: An SSB phase noise floor of -153 dBc/Hz effectively reduces system frequency jitter and improves signal purity, making it suitable for low-noise synthesiser designs;

- High integration: Integrated output resistors eliminate the need for additional external components, simplifying circuit design and reducing PCB layout space;

- Rich feature set: Built-in lock detection and inversion functions, flexibly adapting to system layout and control requirements, enhancing system design flexibility;

- High reliability: Industrial-grade wide operating temperature range (-40°C to 85°C), QFN package with exposed ground pad, excellent thermal dissipation and anti-interference performance, RoHS compliant, suitable for harsh operating environments.

VII. Summary of the HMC3716LP4ETR

The ADI HMC3716LP4ETR is a high-performance HBT digital phase-frequency detector. With its wide operating frequency range of 10 MHz to 1300 MHz, ultra-low phase noise, rich feature set and high reliability, it is the preferred component for phase-frequency detection in high-end RF systems. The application of its advanced HBT process not only enables stable operation across a wide frequency range but also ensures ultra-low phase noise performance. Combined with lock detection and inversion functions, it can be flexibly adapted to a variety of high-end application scenarios, including point-to-point radio, satellite communications and military equipment.

In practical system design, through appropriate impedance matching, power supply and ground design, and component selection, the performance advantages of the HMC3716LP4ETR can be fully utilised to build a stable, high-precision phase-locked loop system. This provides precise phase and frequency control for RF systems, helping to enhance overall system performance and reliability.