LTC6947IUFD#TRPBF

Clock Generators, PLLs, Frequency Synthesizers Overview

The LTC6947IUFD#TRPBF is a high-performance, ultralow noise fractional-N phase-locked loop (PLL) synthesizer from Analog Devices. It integrates a reference divider, phase-frequency detector, charge pump, fractional feedback divider, and VCO output divider within a 28-lead QFN package. The device supports an input frequency range of 350MHz to 6GHz with an output divider ranging from 1 to 6. Key electrical specifications include a normalized in-band phase noise floor of –226dBc/Hz and a wideband output phase noise floor of –157dBc/Hz. It operates on supply voltages of 3.15V to 5.25V and features an SPI-compatible serial interface for configuration.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Ultralow Noise Fractional-N Synthesizer: Features a 4th order ΔΣ modulator providing exceptionally low spurious levels and a normalized in-band phase noise floor of –226dBc/Hz.
• Wide Frequency Range: Supports VCO input frequencies from 350MHz to 6GHz, extendable via an integer output divider (1 through 6).
• Programmable Charge Pump: Offers selectable current settings from 1mA to 11.2mA with high voltage clamps useful for VCO monitoring.
• Differential Output Buffer: User-programmable output power ranging from –4.3dBm to +4.5dBm with mute capability.

Clock Generators, PLLs, Frequency Synthesizers Applications

• Wireless Basestations (LTE, WiMAX, W-CDMA, PCS)
• Broadband Wireless Access Systems
• Microwave Data Links
• Military and Secure Radio Communications
• Test and Measurement Equipment

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the specific ordering suffix #TRPBF confirms the tape and reel packaging format. Confirm the 'I' temperature grade designation matches the required operating junction temperature range of –40°C to 105°C. Ensure compatibility with the 28-lead QFN footprint during procurement planning.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select this component when designing systems requiring fractional-N synthesis with minimal spurious tones up to 6GHz. Consider the integrated output divider if extending the frequency range beyond the VCO's native capabilities is necessary. Evaluate the charge pump current settings against the required loop bandwidth and phase noise performance targets.

Clock Generators, PLLs, Frequency Synthesizers Part Context

This part belongs to the LTC6947 family of ultralow noise PLLs. It is distinct from the integer-N LTC6946 series by its inclusion of a 4th order ΔΣ modulator for fractional division. The IUFD#TRPBF designation specifies the industrial temperature range, plastic QFN package, and tape and reel shipping method.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should consult Analog Devices marketing or technical support for qualified replacements or cross-references.