LTC6945 - Ultralow Noise and Spurious 0.35GHz to 6GHz Integer-N Synthesizer
Features
- Low Noise Integer-N PLL
- 350MHz to 6GHz VCO Input Range
- –226dBc/Hz Normalized In-Band Phase Noise Floor
- –274dBc/Hz Normalized In-Band 1/f Noise
- –157dBc/Hz Wideband Output Phase Noise Floor
- Excellent Spurious Performance
- Output Divider (1 to 6, 50% Duty Cycle)
- Low Noise Reference Buffer
- Output Buffer Muting
- Charge Pump Supply from 3.15V to 5.25V
- Charge Pump Current from 250μA to 11.2mA
- Configurable Status Output
- SPI Compatible Serial Port Control
- PLLWizard Software Design Tool Support
Typical Application
Description
The LTC®6945 is a high performance, low noise, 6GHz phaselocked loop (PLL), including a reference divider, phasefrequency detector (PFD) with phase-lock indicator, charge pump, integer feedback divider and VCO output divider.
The part features a buffered, programmable VCO output divider with a range of 1 through 6. The differential, low noise output buffer has user-programmable output power ranging from –6dBm to 3dBm, and may be muted through either a digital input pin or software.
The low noise reference buffer outputs a typical 0dBm square wave directly into a 50Ω impedance from 10MHz to 250MHz, or may be disabled through software.
The ultralow noise charge pump contains selectable high and low voltage clamps useful for VCO monitoring, and also may be set to provide a V+/2 bias.
All device settings are controlled through a SPI-compatible serial port.
Packaging
For complete and up to date package information and drawings, please refer to our packaging page
QFN-28
Order Info
- Part numbers ending in PBF are lead free. Please contact LTC marketing for information on lead based finish parts.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) | Price (1k)* | RoHS Data |
|---|---|---|---|---|---|---|
| LTC6945IUFD#PBF | QFN | 28 | I | $7.07 | $4.95 | View |
| LTC6945IUFD#TRPBF | QFN | 28 | I | $5.01 | View | |
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC1649A-A | LTC6945 Demo | Ultralow Noise and Spurious 6GHz Integer-N Synthesizer, VCO=902-928Hz, (Req DC590) | $125.00 | |
| Buy Now | |||
Companion Boards
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC590B | USB Serial Controller for Linear Technology QuikEval Demo Boards | $50.00 | |
| Buy Now | |||
Applications
- Wireless Base Stations (LTE, WiMAX, W-CDMA, PCS)
- Broadband Wireless Access
- Microwave Data Links
- Military and Secure Radio
- Test and Measurement
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Simulate
LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. To download LTspice IV and other FREE simulation tools, please visit our Design Simulation page.
Linear Technology PLLWizard is used to communicate with the LTC6945 and LTC6946 synthesizers. It uses the DC590 controller to translate between USB and SPI-compatible serial communications formats. It also includes advanced PLL design and simulation capabilities. You may use it to:
- Recommend part parameters based on your frequency plan
- Design noise-optimized loop filters
- Simulate loop frequency response and stability
- Simulate VCO and Reference source noise
- Simulate output noise characterisics and statistics
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.