SNAS624B March   2014  – May 2015 LMX2492 , LMX2492-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2  Applications
  3. 3 Description
  4. 4 Simplified Schematic
  5. 5 Revision History
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Storage Conditions
    3. 7.3 ESD Ratings
    4. 7.4 Recommended Operating Conditions
    5. 7.5 Thermal Information
    6. 7.6 Electrical Characteristics
    7. 7.7 Timing Requirements, Programming Interface (CLK, DATA, LE)
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1  Overview
    2. 8.2  Functional Block Diagram
    3. 8.3  Feature Description
      1. 8.3.1  OSCin Input
      2. 8.3.2  OSCin Doubler
      3. 8.3.3  R Divider
      4. 8.3.4  PLL N Divider
      5. 8.3.5  Fractional Circuitry
      6. 8.3.6  PLL Phase Detector and Charge Pump
      7. 8.3.7  External Loop Filter
      8. 8.3.8  Fastlock and Cycle Slip Reduction
      9. 8.3.9  Lock Detect and Charge Pump Voltage Monitor
        1. 8.3.9.1 Charge Pump Voltage Monitor
        2. 8.3.9.2 Digital Lock Detect
      10. 8.3.10 FSK/PSK Modulation
      11. 8.3.11 Ramping Functions
        1. 8.3.11.1 Ramp Count
        2. 8.3.11.2 Ramp Comparators and Ramp Limits
      12. 8.3.12 Power on Reset (POR)
    4. 8.4  Device Functional Modes
      1. 8.4.1 Continuous Frequency Generator
        1. 8.4.1.1 Integer Mode Operation
        2. 8.4.1.2 Fractional Mode Operation
      2. 8.4.2 Modulated Waveform Generator
    5. 8.5  Programming
      1. 8.5.1 Loading Registers
    6. 8.6  Register Map
    7. 8.7  Register Field Descriptions
      1. 8.7.1 POWERDOWN and Reset Fields
      2. 8.7.2 Dividers and Fractional Controls
        1. 8.7.2.1 Speed Up Controls (Cycle Slip Reduction and Fastlock)
    8. 8.8  Lock Detect and Charge Pump Monitoring
    9. 8.9  TRIG1,TRIG2,MOD, and MUXout Pins
    10. 8.10 Ramping Functions
    11. 8.11 Individual Ramp Controls
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Performance Plot - Sawtooth Waveform Example
      4. 9.2.4 Application Performance Plot - Flat Top Triangle Waveform
      5. 9.2.5 Applications Performance Plot -- Complex Triggered Ramp
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

1 Features

  • -227 dBc/Hz Normalized PLL Noise
  • 500 MHz - 14 GHz Wideband PLL
  • 3.15 - 5.25 V Charge Pump PLL Supply
  • Versatile Ramp / Chirp Generation
  • 200 MHz Max Phase Detector Frequency
  • FSK / PSK Modulation Pin
  • Digital Lock Detect
  • Single 3.3 V Supply Capability
  • Automotive 125°C Q100 Grade 1 Qualification
  • Non-Automotive (LMX2492) Option

2 Applications

  • Automotive FMCW Radar
  • Military Radar
  • Microwave Backhaul
  • Test and Measurement
  • Satellite Communications
  • Wireless Infrastructure
  • Sampling Clock for High Speed ADC/DAC

3 Description

The LMX2492/92-Q1 is a low noise 14 GHz wideband delta-sigma fractional N PLL with ramp and chirp generation. It consists of a phase frequency detector, programmable charge pump, and high frequency input for the external VCO. The LMX2492/92-Q1 supports a broad and flexible class of ramping capabilities, including FSK, PSK, and configurable piecewise linear FM modulation profiles of up to 8 segments. It supports fine PLL resolution and fast ramp with up to a 200 MHz phase detector rate. The LMX2492/92-Q1 allows any of its registers to be read back. The LMX2492/92-Q1 can operate with a single 3.3 V supply. Moreover, supporting up to 5.25 V charge pump can eliminate the need of external amplifier, leading to a simpler solution with improved phase noise performance.

Device Information

PART NUMBER PACKAGE BODY SIZE (NOM)
LMX2492-Q1RTW WQFN (24) 4.00 mm x 4.00 mm
LMX2492RTW WQFN (24) 4.00 mm x 4.00 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

4 Simplified Schematic

LMX2492 LMX2492-Q1 sch_main_snas624.gif