LTC6946IUFD-1

Clock Generators, PLLs, Frequency Synthesizers Overview

The LTC6946IUFD-1 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 2.24 GHz to 3.74 GHz. The device features a programmable output divider ranging from 1 to 6, enabling RF output frequencies from 0.373 GHz to 3.74 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. The charge pump current is adjustable from 250 µA to 11.2 mA, and the unit is controlled via an SPI-compatible serial port.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Integrated low-noise VCO with no external components required
• Programmable output divider (1 to 6) for flexible frequency coverage
• Adjustable charge pump current from 250 µA to 11.2 mA
• SPI-compatible serial port control with configurable status output

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 certified suppliers. Confirm the part marking '69461' matches the ordering suffix. Ensure the QFN-28 package condition meets storage requirements. Check for RoHS compliance documentation as specified in the datasheet. Validate that the specific revision of the datasheet aligns with the manufacturing batch.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select the LTC6946IUFD-1 variant specifically when the required VCO frequency falls between 2.24 GHz and 3.74 GHz. Other variants cover higher ranges: -2 (3.08–4.91 GHz), -3 (3.84–5.79 GHz), and -4 (4.20–6.39 GHz). Consider the output divider setting to achieve the desired final RF frequency. Ensure the power supply voltages match the specified ranges: 3.15V–3.45V for digital/RF supplies and 4.75V–5.25V for VCO/CP supplies.

Clock Generators, PLLs, Frequency Synthesizers Part Context

This component belongs to the LTC6946 family of integer-N synthesizers. The IUFD-1 suffix denotes the industrial temperature range (-40°C to 105°C) and the UFD-28 plastic QFN package. The '#PBF' indicates a lead-free finish. The device integrates a reference divider, phase-frequency detector, charge pump, and VCO output divider into a single chip.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

Direct functional replacements within the same package and pinout include LTC6946IUFD-2#PBF, LTC6946IUFD-3#PBF, and LTC6946IUFD-4#PBF, provided the application frequency requirements align with their respective VCO ranges. Verify thermal characteristics and supply voltage compatibility before substitution.