LTC6946IUFD-3

Clock Generators, PLLs, Frequency Synthesizers Overview

The LTC6946IUFD-3 is an ultralow noise and spurious integer-N synthesizer with a fully integrated voltage-controlled oscillator (VCO). It operates within a VCO frequency range of 3.84 GHz to 5.79 GHz. The device features a programmable output divider ranging from 1 to 6, enabling RF output frequencies from 0.640 GHz to 5.790 GHz. Key electrical specifications include a normalized in-band phase noise floor of –226 dBc/Hz and a wideband output phase noise floor of –157 dBc/Hz. It utilizes a charge pump with adjustable current from 250 µA to 11.2 mA and is controlled via an SPI-compatible serial port.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Integrated low-noise VCO with no external components required for calibration
• Programmable output divider (1 to 6) providing flexible frequency coverage
• Ultra-low phase noise performance: –226 dBc/Hz normalized in-band floor
• Adjustable charge pump current from 250 µA to 11.2 mA with selectable clamps

Clock Generators, PLLs, Frequency Synthesizers Applications

• Wireless base stations (LTE, WiMAX, W-CDMA, PCS)
• Broadband wireless access systems
• Military and secure radio communications
• Test and measurement equipment

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify component authenticity through authorized Analog Devices distributors or direct manufacturer channels. Confirm the specific -3 suffix corresponds to the 3.84 GHz to 5.79 GHz VCO frequency range. Ensure compliance with RoHS directives as indicated by the #PBF lead finish designation. Check for end-of-life status or alternative sourcing if long-term supply stability is required.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select the LTC6946IUFD-3 variant specifically when the target VCO frequency falls between 3.84 GHz and 5.79 GHz. Consider the output divider setting to determine the final RF output range, which spans 0.640 GHz to 5.790 GHz. Evaluate the required charge pump current and loop bandwidth against the available 12 settings to optimize phase noise and lock time performance for the specific application.

Clock Generators, PLLs, Frequency Synthesizers Part Context

This component belongs to the LTC6946 family of high-performance PLLs. Other variants include the LTC6946-1 (2.24–3.74 GHz), LTC6946-2 (3.08–4.91 GHz), and LTC6946-4 (4.20–6.39 GHz). All members share the same QFN-28 package and functional architecture but differ in their internal VCO tuning ranges.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

Direct pin-to-pin replacements within the same family are limited to other LTC6946 variants with compatible frequency bands. No other part numbers are confirmed as direct substitutes in public documentation.