SNVSAY4F
august 2018 – august 2023
LM5155-Q1
,
LM51551-Q1
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
11
Power Supply Recommendations
12
Layout
12.1
Layout Guidelines
12.2
Layout Examples
13
Device and Documentation Support
13.1
Device Support
13.1.1
Third-Party Products Disclaimer
13.1.2
Development Support
13.1.2.1
Custom Design With WEBENCH® Tools
13.2
Documentation Support
13.2.1
Related Documentation
13.3
Receiving Notification of Documentation Updates
13.4
Support Resources
13.5
Trademarks
13.6
Electrostatic Discharge Caution
13.7
Glossary
14
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
DSS|12
MPDS336C
Thermal pad, mechanical data (Package|Pins)
DSS|12
QFND398B
Orderable Information
snvsay4f_oa
snvsay4f_pm
8.6
Typical Characteristics
Figure 8-1
Frequency vs RT Resistance
Figure 8-3
V
VCC
vs I
VCC
Figure 8-5
Peak Current Limit vs Duty Cycle
Figure 8-7
FB Reference vs Temperature
Figure 8-9
I
OPERATING(BIAS)
including RT current vs V
BIAS
Figure 8-11
I
SHUTDOWN
vs Temperature
Figure 8-13
I
SS
vs Temperature
Figure 8-15
UVLO Threshold vs Temperature
Figure 8-2
Frequency vs Temperature
Figure 8-4
V
VCC
vs V
BIAS
(No Load)
Figure 8-6
Current Limit Threshold vs Temperature
Figure 8-8
EN Threshold vs Temperature
Figure 8-10
I
SHUTDOWN(BIAS)
vs V
BIAS
Figure 8-12
t
ON(MIN)
vs Frequency
Figure 8-14
Peak Driver Current vs VCC
Figure 8-16
Maximum Duty Cycle vs Frequency