SNVS485I
June 2007 – September 2018
LM2735
PRODUCTION DATA.
1
Features
2
Applications
3
Description
Device Images
Typical Boost Application Circuit
Efficiency vs Load Current VO = 12 V
4
Revision History
5
Pin Configuration and Functions
Pin Functions
6
Specifications
6.1
Absolute Maximum Ratings
6.2
ESD Ratings: LM2735
6.3
Recommended Operating Conditions
6.4
Thermal Information
6.5
Electrical Characteristics
6.6
Typical Characteristics
7
Detailed Description
7.1
Overview
7.1.1
Theory of Operation
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
Current Limit
7.3.2
Thermal Shutdown
7.3.3
Soft Start
7.3.4
Compensation
7.4
Device Functional Modes
7.4.1
Enable Pin and Shutdown Mode
8
Application and Implementation
8.1
Application Information
8.2
Typical Applications
8.2.1
LM2735X SOT-23 Design Example 1
8.2.1.1
Design Requirements
8.2.1.2
Detailed Design Procedure
8.2.1.2.1
Custom Design With WEBENCH® Tools
8.2.1.2.2
Inductor Selection
8.2.1.2.3
Input Capacitor
8.2.1.2.4
Output Capacitor
8.2.1.2.5
Setting the Output Voltage
8.2.1.3
Application Curves
8.2.2
LM2735Y SOT-23 Design Example 2
8.2.3
LM2735X WSON Design Example 3
8.2.4
LM2735Y WSON Design Example 4
8.2.5
LM2735Y MSOP-PowerPAD Design Example 5
8.2.6
LM2735X SOT-23 Design Example 6
8.2.7
LM2735Y SOT-23 Design Example 7
8.2.8
LM2735X SOT-23 Design Example 8
8.2.9
LM2735Y SOT-23 Design Example 9
8.2.10
LM2735X WSON Design Example 10
8.2.11
LM2735Y WSON Design Example 11
8.2.12
LM2735X WSON SEPIC Design Example 12
8.2.13
LM2735Y MSOP-PowerPAD SEPIC Design Example 13
8.2.14
LM2735X SOT-23 LED Design Example 14
8.2.15
LM2735Y WSON FlyBack Design Example 15
8.2.16
LM2735X SOT-23 LED Design Example 16 VRAIL > 5.5 V Application
8.2.17
LM2735X SOT-23 LED Design Example 17 Two-Input Voltage Rail Application
8.2.18
SEPIC Converter
8.2.18.1
Detailed Design Procedure
8.2.18.1.1
SEPIC Design Guide
8.2.18.1.2
Small Ripple Approximation
8.2.18.1.3
Steady State Analysis With Loss Elements
9
Power Supply Recommendations
10
Layout
10.1
Layout Guidelines
10.1.1
WSON Package
10.2
Layout Examples
10.3
Thermal Considerations
10.3.1
Definitions
10.3.2
PCB Design With Thermal Performance in Mind
10.3.3
LM2735 Thermal Models
10.3.4
Calculating Efficiency, and Junction Temperature
10.3.4.1
Example Efficiency Calculation
10.3.5
Calculating RθJA and RΨJC
10.3.5.1
Procedure
10.3.5.2
Example From Previous Calculations
11
Device and Documentation Support
11.1
Device Support
11.1.1
Third-Party Products Disclaimer
11.1.2
Development Support
11.1.2.1
Custom Design With WEBENCH® Tools
11.2
Documentation Support
11.2.1
Related Documentation
11.3
Community Resources
11.4
Trademarks
11.5
Electrostatic Discharge Caution
11.6
Glossary
12
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
NGG|6
MPDS395
DGN|8
MPDS046G
DBV|5
MPDS018T
Thermal pad, mechanical data (Package|Pins)
DGN|8
PPTD274A
Orderable Information
snvs485i_oa
snvs485i_pm
1
Features
Input Voltage Range: 2.7 V to 5.5 V
Output Voltage Range: 3 V to 24 V
2.1-A Switch Current Over Full Temperature Range
Current-Mode Control
Logic High Enable Pin
Ultra-Low Standby Current of 80 nA in Shutdown
170-mΩ NMOS Switch
±2% Feedback Voltage Accuracy
Ease-of-Use, Small Total Solution Size
Internal Soft Start
Internal Compensation
Two Switching Frequencies
520 kHz (LM2735-Y)
1.6 MHz (LM2735-X)
Uses Small Surface Mount Inductors and Chip Capacitors
Tiny SOT-23, WSON, and MSOP-PowerPAD™ Packages
Create a Custom Design Using the LM2735 With
WEBENCH® Power Designer