SNOSB38C January   2009  – November 2017 LM3241

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 System Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Circuit Operation
      2. 7.3.2 Internal Synchronization Rectification
      3. 7.3.3 Current Limiting
      4. 7.3.4 Dynamically Adjustable Output Voltage
      5. 7.3.5 Thermal Overload Protection
      6. 7.3.6 Soft Start
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Mode Operation
      2. 7.4.2 Eco-mode™ Operation
      3. 7.4.3 Shutdown Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Setting the Output Voltage
        2. 8.2.2.2 Inductor Selection
          1. 8.2.2.2.1 Method 1
          2. 8.2.2.2.2 Method 2
        3. 8.2.2.3 Capacitor Selection
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 DSBGA Package Assembly and Use
      2. 10.1.2 Board Layout Considerations
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • 6-MHz (typ.) PWM Switching Frequency
  • Operates from a Single Li-Ion Cell (2.7 V to 5.5 V)
  • Adjustable Output Voltage (0.6 V to 3.4 V)
  • 750-mA Maximum Load Capability
  • High Efficiency (95% typ. at 3.9 VIN, 3.3 VOUT at 500 mA)
  • Automatic Eco-mode™ and PWM Mode Change
  • 6-Bump DSBGA Package
  • Current Overload Protection
  • Thermal Overload Protection
  • Soft Start Function
  • CIN and COUT are 0402 (1005) Case Size and 6.3 V of Rated-Voltage Ceramic Capacitor
  • Small Chip Inductor in 0805 (2012) Case Size

2 Applications

  • Battery-Powered 3G and 4G Power Amplifiers
  • Hand-Held Radios
  • RF PC Cards
  • Battery-Powered RF Devices

3 Description

The LM3241 is a DC-DC converter optimized for powering RF power amplifiers (PAs) from a single Lithium-Ion cell. The device can also be used in many other applications. The device steps down an input voltage from 2.7 V to 5.5 V to an adjustable output voltage from 0.6 V to 3.4 V. The output voltage is set using a VCON analog input for controlling power levels and efficiency of the RF PA.

The LM3241 offers three modes of operation. In PWM mode the device operates at a fixed frequency of 6 MHz (typical) which minimizes RF interference when driving medium-to-heavy loads. At light-load conditions, the device enters into Eco-mode automatically and operates with reduced switching frequency. In Eco-mode, the quiescent current is reduced and extends the battery life. Shutdown mode turns the device off and reduces battery consumption to 0.1 µA (typical).

The LM3241 is available in a 6-bump lead-free DSBGA package. A high-switching frequency (6 MHz) allows use of tiny surface-mount components. Only three small external surface-mount components, an inductor and two ceramic capacitors are required.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM3241 DSBGA (6) 1.50 mm × 1.30 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application

LM3241 30090401.gif