SNVSCL1
November 2023
LM25185
PRODUCTION DATA
1
1
Features
2
Applications
3
Description
4
Description (continued)
5
Pin Configuration and Functions
6
Specifications
6.1
Absolute Maximum Ratings
6.2
ESD Ratings
6.3
Recommended Operating Conditions
6.4
Thermal Information
6.5
Electrical Characteristics
6.6
Typical Characteristics
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
Power MOSFET Gate Driver
7.3.2
PSR Flyback Modes of Operation
7.3.3
High Voltage VCC Regulator
7.3.4
Setting the Output Voltage
7.3.4.1
Diode Thermal Compensation
7.3.5
Control Loop Error Amplifier
7.3.6
Precision Enable
7.3.7
Configurable Soft Start
7.3.8
Minimum On-Time and Off-Time
7.3.9
Current Sensing and Overcurrent Protection
7.3.10
Thermal Shutdown
7.4
Device Functional Modes
7.4.1
Shutdown Mode
7.4.2
Standby Mode
7.4.3
Active Mode
8
Application and Implementation
8.1
Application Information
8.2
Typical Applications
8.2.1
Design 1: Wide VIN, Low IQ PSR Flyback Converter Rated at 16.4 V, 1 A
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
Custom Design With Excel Quickstart Tool
8.2.1.2.3
Flyback Transformer T1 and Current-Sense Resistor (RCS)
8.2.1.2.4
Flyback Diode – DFLY
8.2.1.2.5
Leakage Inductance Clamp Circuit – DF, DCLAMP
8.2.1.2.6
Feedback Resistor – RFB
8.2.1.2.7
Thermal Compensation Resistor – RTC
8.2.1.2.8
UVLO Resistors – RUV1, RUV2
8.2.1.2.9
Soft-Start Capacitor – CSS
8.2.1.2.10
Compensation Components
8.2.1.3
Application Curves
8.3
Power Supply Recommendations
8.4
Layout
8.4.1
Layout Guidelines
8.4.2
Layout Examples
9
Device and Documentation Support
9.1
Device Support
9.1.1
Development Support
9.1.1.1
Custom Design With WEBENCH® Tools
9.2
Documentation Support
9.2.1
Related Documentation
9.3
Receiving Notification of Documentation Updates
9.4
Support Resources
9.5
Trademarks
9.6
Electrostatic Discharge Caution
9.7
Glossary
10
Revision History
11
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
PWP|14
MPDS370A
Thermal pad, mechanical data (Package|Pins)
PWP|14
PPTD022AA
Orderable Information
snvscl1_oa
snvscl1_pm
1
Features
Functional Safety-Capable
Documentation available to aid functional safety system design
4.5-V to
42
-V wide input voltage range
Extended power range from less than 1 W to more than 50 W
Robust PSR flyback design for reliable and rugged applications
Robust design with only a transformer crossing the isolation barrier
±1.5% total output regulation accuracy
Optional VOUT temperature compensation
Input UVLO and thermal shutdown protection
Hiccup-mode overcurrent fault protection
0.9-mm HV-LV pin spacing in 14-pin HTSSOP package
–40°C to +150°C junction temperature range
Integration reduces design size and cost
No optocoupler or transformer auxiliary winding required for V
OUT
regulation
2-A peak sink and 1-A peak source high-current power MOSFET gate driver
High efficiency with best-in-class active I
Q
Quasi-resonant switching in boundary conduction mode (BCM) at heavy load
External VCC option for improved efficiency
High light-load efficiency with lowest I
Q
(25-µA typical with external VCC)
Single and multiple output implementations
Ultra-low conducted and radiated EMI signatures
Soft switching avoids diode reverse recovery
Designed for CISPR 32 EMI requirement
Create a custom design using
LM25185
with
WEBENCH®
Power Designer