SNWS014D March   2004  – June 2025 LMV242 , LMV2421

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 Recommended Operating Conditions
    3. 5.3 Electrical Characteristics for 2.6V
    4. 5.4 Electrical Characteristics for 5V
    5. 5.5 Timing Diagram
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Functional Block Diagram
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Power-Control Principles
      2. 7.1.2 Power Amplifier Controlled Loop
        1. 7.1.2.1 General Overview
        2. 7.1.2.2 Typical PA Closed Loop Control Setup
          1. 7.1.2.2.1 Power Control Over Wide Dynamic Range
      3. 7.1.3 Attenuation Between the Coupler and LMV242x Detector
      4. 7.1.4 Control of the LMV242x
        1. 7.1.4.1 VRAMP Signal
        2. 7.1.4.2 Transmit Enable
        3. 7.1.4.3 Band Select (LMV242 Only)
        4. 7.1.4.4 Analog Output
      5. 7.1.5 Frequency Compensation
    2. 7.2 Typical Application
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • NGY|10
Thermal pad, mechanical data (Package|Pins)
Orderable Information

5.5 Timing Diagram

To meet the time mask specifications for GSM, a good timing between the control signals and the RF signal is essential. According to the specifications the PA RF output power needs to ramp within 28μs with minimum overshoot. To achieve this, ramp the output of the PA controller at the same time as the RF signal from the baseband. The ramp signal sets the controllers output to the required value, where the loop requires a certain time to set this output. Therefore, set the VRAMP pin to the desired value some time before the desired output. How much time depends on the setup and the PA used. If the controllers shutdown functionality is used, then set the shutdown high about 6μs before the ramp is set high.

The control loop can be configured by the following variables:

  • Lead time TX_EN event vs start GSM burst
  • Lead time VRAMP vs start GSM burst
  • Ramp profile
  • Loop compensation
LMV242 LMV2421 Timing VRAMP vs RF Signal Figure 5-1 Timing VRAMP vs RF Signal