SNVS449O June   2007  – April 2015 LM3668

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 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 Buck Operation
      2. 8.3.2 Boost Operation
      3. 8.3.3 Internal Synchronous Rectification
      4. 8.3.4 Current Limit Protection
      5. 8.3.5 Undervoltage Protection
      6. 8.3.6 Short Circuit Protection
      7. 8.3.7 Shutdown
      8. 8.3.8 Thermal Shutdown
      9. 8.3.9 Start-Up
    4. 8.4 Device Functional Modes
      1. 8.4.1 PWM Operation
      2. 8.4.2 PFM Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 MODE/SYNC Pin
      2. 9.1.2 VSEL Pin
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 Maximum Current
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Inductor Selection
        2. 9.2.2.2 Input Capacitor Selection
        3. 9.2.2.3 Output Capacitor Selection
      3. 9.2.3 Application Curves
  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 Third-Party Products Disclaimer
      2. 12.1.2 Documentation Support
        1. 12.1.2.1 Related Documentation
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

6 Pin Configuration and Functions

DQB Package
12-Pin WSON
Top View
LM3668 20191402.gif
DQB Package
12-Pin WSON
Bottom View
LM3668 20191403.gif

Pin Functions(1)

PIN TYPE DESCRIPTION
NO. NAME
1 VOUT A Connect to output capacitor.
2 SW2 A Switching node connection to the internal PFET switch (P2) and NFET synchronous rectifier (N2).
3 PGND G Power ground.
4 SW1 A Switching node connection to the internal PFET switch (P1) and NFET synchronous rectifier (N1).
5 PVIN P Supply to the power switch, connect to the input capacitor.
6 EN I Enable input. Set this digital input high for normal operation. For shutdown, set low.
7 VDD P Signal supply input. If board layout is not optimum an optional 1-µF ceramic capacitor is suggested as close to this pin as possible.
8 NC - No connect. Connect this pin to SGND on PCB layout.
9 SGND G Analog and Control Ground.
10 MODE/SYNC I Mode = LOW, Automatic Mode. Mode= HI, forced PWM Mode. SYNC = external clock synchronization from 1.6 MHz to 2.7 MHz.(When SYNC function is used, device is forced in PWM mode).
11 VSEL I Voltage selection pin; (for example, 2.8-V-3.3-V option) logic input low (or GND) = 2.8 V and logic high = 3.3 V (or VIN) to set output voltage.
12 FB A Feedback analog input. Connect to the output at the output filter.
DAP DAP - Die Attach Pad, connect the DAP to SGND on PCB layout to enhance thermal performance. It should not be used as a primary ground connection.
(1) A: Analog Pin, G: Ground Pin, P: Power Pin, I: Digital Input Pin