Overview
The LTC6948IUFD-4#PBF, produced by Analog Devices Inc., is a high-performance, low-noise phase-locked loop (PLL) synthesizer with a fully integrated voltage-controlled oscillator (VCO). This device is designed for applications requiring high frequency stability and low phase noise. It features a fractional-N PLL architecture, which includes a reference divider, phase-frequency detector (PFD), ultralow noise charge pump, fractional feedback divider, and VCO output divider. The advanced 4th order Δ∑ modulator in the fractional divider ensures exceptionally low spurious levels and wide loop bandwidths, resulting in extremely low integrated phase noise values.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| Reference Input Frequency (fREF) | 10 | 425 | MHz | |
| Reference Input Signal Level (VREF) | 0.5 | 2 | 2.7 | VP-P |
| VCO Frequency Range (fVCO) | 4.20 | 6.39 | GHz | |
| KVCO Tuning Sensitivity | 4.5 | 6.5 | %Hz/V | |
| RF Output Frequency (fRF) | 0.373 | 6.39 | GHz | |
| Output Divider Range | 1 | 6 | ||
| Output Duty Cycle | 50 | % | ||
| Output Resistance (Single-Ended) | 100 | 136 | 175 | Ω |
Key Features
- Ultralow noise fractional-N PLL synthesizer with integrated VCO.
- Advanced 4th order Δ∑ modulator for low spurious levels and wide loop bandwidths.
- Programmable VCO output divider with a range of 1 through 6.
- Low noise charge pump and phase-frequency detector.
- Reference divider and fractional feedback divider included.
- Output frequency range from 0.373 GHz to 6.39 GHz.
- High tuning sensitivity with KVCO ranging from 4.5 to 6.5 %Hz/V.
Applications
The LTC6948IUFD-4#PBF is suitable for various high-frequency applications, including:
- RF and microwave systems.
- Communications analog front ends.
- Frequency dividers, multipliers, and detectors.
- I/Q modulators and demodulators.
- Phase locked loop (PLL) synthesizers and translation loops.
- Quadrature digital up converters (QDUC).
- RF integrated transmitters, receivers, and transceivers.
- Wireless sensor networks.
Q & A
- What is the frequency range of the VCO in the LTC6948IUFD-4#PBF?
The VCO frequency range is from 4.20 GHz to 6.39 GHz. - What is the tuning sensitivity of the VCO?
The KVCO tuning sensitivity ranges from 4.5 to 6.5 %Hz/V. - What is the output divider range of the LTC6948IUFD-4#PBF?
The output divider range is from 1 to 6. - What is the typical output duty cycle?
The typical output duty cycle is 50%. - What is the output resistance of the RF output?
The output resistance is between 100 Ω and 175 Ω (single-ended). - What type of modulator is used in the fractional divider?
An advanced 4th order Δ∑ modulator is used. - What are the reference input frequency and signal level specifications?
The reference input frequency is between 10 MHz and 425 MHz, and the signal level is between 0.5 VP-P and 2.7 VP-P. - What are some common applications of the LTC6948IUFD-4#PBF?
Common applications include RF and microwave systems, communications analog front ends, and wireless sensor networks. - Does the LTC6948IUFD-4#PBF have an integrated charge pump?
Yes, it includes an ultralow noise charge pump. - What is the purpose of the Δ∑ modulator in the LTC6948IUFD-4#PBF?
The Δ∑ modulator ensures exceptionally low spurious levels and allows for wide loop bandwidths, resulting in extremely low integrated phase noise values.
