SNVSB75E
december 2018 – august 2023
LM5155
,
LM51551
PRODUCTION DATA
1
1
Features
2
Applications
3
Description
4
Revision History
5
Description (continued)
6
Device Comparison Table
7
Pin Configuration and Functions
8
Specifications
8.1
Absolute Maximum Ratings
8.2
ESD Ratings
8.3
Recommended Operating Conditions
8.4
Thermal Information
8.5
Electrical Characteristics
8.6
Typical Characteristics
9
Detailed Description
9.1
Overview
9.2
Functional Block Diagram
9.3
Feature Description
9.3.1
Line Undervoltage Lockout (UVLO/SYNC Pin)
9.3.2
High Voltage VCC Regulator (BIAS, VCC Pin)
9.3.3
Soft Start (SS Pin)
9.3.4
Switching Frequency (RT Pin)
9.3.5
Clock Synchronization (UVLO/SYNC Pin)
9.3.6
Current Sense and Slope Compensation (CS Pin)
9.3.7
Current Limit and Minimum On-time (CS Pin)
9.3.8
Feedback and Error Amplifier (FB, COMP Pin)
9.3.9
Power-Good Indicator (PGOOD Pin)
9.3.10
Hiccup Mode Overload Protection (LM51551 Only)
9.3.11
Maximum Duty Cycle Limit and Minimum Input Supply Voltage
9.3.12
MOSFET Driver (GATE Pin)
9.3.13
Overvoltage Protection (OVP)
9.3.14
Thermal Shutdown (TSD)
9.4
Device Functional Modes
9.4.1
Shutdown Mode
9.4.2
Standby Mode
9.4.3
Run Mode
10
Application and Implementation
10.1
Application Information
10.2
Typical Application
10.2.1
Design Requirements
10.2.2
Detailed Design Procedure
10.2.2.1
Custom Design With WEBENCH® Tools
10.2.2.2
Recommended Components
10.2.2.3
Inductor Selection (LM)
10.2.2.4
Output Capacitor (COUT)
10.2.2.5
Input Capacitor
10.2.2.6
MOSFET Selection
10.2.2.7
Diode Selection
10.2.2.8
Efficiency Estimation
10.2.3
Application Curve
10.3
System Examples
10.4
Power Supply Recommendations
10.5
Layout
10.5.1
Layout Guidelines
10.5.2
Layout Examples
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
Receiving Notification of Documentation Updates
11.4
Support Resources
11.5
Trademarks
11.6
Electrostatic Discharge Caution
11.7
Glossary
12
Mechanical, Packaging, and Orderable Information
1
Features
Functional Safety-Capable
Documentation available to aid functional safety system design
Wide input operating range for battery applications
3.5-V to 45-V operating range
2.97-V to 16-V when BIAS = VCC
Minimum boost supply voltage 1.5 V when BIAS ≥ 3.5 V
Input transient protection up to 50 V
Minimized battery drain
Low shutdown current (I
Q
≤ 2.6 µA)
Low operating current (I
Q
≤ 480 µA)
Small solution size and low cost
Maximum switching frequency of 2.2 MHz
12-Pin WSON package (3 mm × 2 mm)
Integrated error amplifier allows primary-side regulation without optocoupler (flyback)
Minimized undershoot during cranking (start-stop application)
Higher efficiency with low-power dissipation
100-mV ±7% Low current limit threshold
Strong 1.5-A peak standard MOSFET driver
Supports external VCC supply
Avoid AM band interference and crosstalk
Optional clock synchronization
Dynamically programmable switching frequency from 100 kHz to 2.2 MHz
Integrated protection features
Constant peak current limiting over input voltage
Optional hiccup mode short-circuit protection (see the
Device Comparison Table
)
Programmable line UVLO
OVP protection
Thermal shutdown
Accurate ±1% accuracy feedback reference
Programmable extra slope compensation
Adjustable soft start
PGOOD indicator
Create a custom design using the LM5155x with the
WEBENCH®
power designer