SNVSCF2A
November 2025 – May 2026
LM65680
PRODMIX
1
1
Features
2
Applications
3
Description
4
Related Products
5
Pin Configuration and Functions
5.1
Wettable Flanks
5.2
Pinout Design for Clearance and FMEA
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 Descriptions
7.3.1
Input Voltage Range (VIN1, VIN2)
7.3.2
High-Voltage Bias Supply Subregulator (VCC, BIAS)
7.3.3
Precision Enable and Adjustable Input Voltage UVLO (EN/UVLO)
7.3.4
Output Voltage Setpoint (FB, BIAS)
7.3.5
Switching Frequency (RT)
7.3.6
Mode Selection and Clock Synchronization (MODE/SYNC)
7.3.6.1
Clock Synchronization
7.3.6.2
Clock Locking
7.3.7
Device Configuration (CNFG/SYNCOUT)
7.3.8
Dual-Random Spread Spectrum (DRSS)
7.3.9
High-Side MOSFET Gate Drive (BST)
7.3.10
Configurable Soft Start (SS)
7.3.10.1
Recovery From Dropout
7.3.11
Protection Features
7.3.11.1
Power-Good Monitor (PG)
7.3.11.2
Overcurrent and Short-Circuit Protection
7.3.11.3
Hiccup-Mode Protection
7.3.11.4
Thermal Shutdown
7.3.12
Two-Phase, Single-Output Operation
7.4
Device Functional Modes
7.4.1
Shutdown Mode
7.4.2
Active Mode
8
Application and Implementation
8.1
Application Information
8.1.1
Power Train Components
8.1.1.1
Buck Inductor
8.1.1.2
Output Capacitors
8.1.1.3
Input Capacitors
8.1.1.4
EMI Filter
8.1.2
Error Amplifier and Compensation
8.1.3
Maximum Ambient Temperature
8.1.3.1
Derating Curves
8.2
Typical Applications
8.2.1
Design 1 – 5V, 8A Synchronous Buck Regulator With Wide Input Voltage Range and High Efficiency
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
Choosing the Switching Frequency
8.2.1.2.3
Buck Inductor Selection
8.2.1.2.4
Input Capacitor Selection
8.2.1.2.5
Output Capacitors
8.2.1.2.6
Output Voltage Setpoint
8.2.1.2.7
Compensation Components
8.2.1.2.8
Setting the Input Voltage UVLO
8.2.1.2.9
EMI Mitigation, RDRSS
8.2.1.2.10
Bootstrap Capacitor, CBST
8.2.1.3
Application Curves
8.2.2
Design 2 – High Efficiency, 48V to 12V, 8A, 400kHz Synchronous Buck Regulator
8.2.2.1
Design Requirements
8.2.2.2
Detailed Design Procedure
8.2.2.2.1
Buck Inductor Selection
8.2.2.2.2
Input Capacitor Selection
8.2.2.2.3
Output Capacitors
8.2.2.2.4
Output Voltage Setpoint
8.2.2.2.5
Compensation Components
8.2.2.2.6
Feedforward Capacitor
8.2.2.2.7
Soft-Start Capacitor
8.2.2.3
Application Curves
8.3
Best Design Practices
8.4
Power Supply Recommendations
8.5
Layout
8.5.1
Layout Guidelines
8.5.1.1
Thermal Design and Layout
8.5.2
Layout Example
9
Device and Documentation Support
9.1
Device Support
9.1.1
Third-Party Products Disclaimer
9.1.2
Development Support
9.1.2.1
Custom Design With WEBENCH® Tools
9.2
Documentation Support
9.2.1
Related Documentation
9.2.1.1
Low-EMI Design Resources
9.2.1.2
Thermal Design Resources
9.2.1.3
Multiphase Design Resources
9.2.1.4
PCB Layout Resources
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
1
Features
Functional Safety-Capable
Documentation available to aid IEC 61508-2 system design
Versatile synchronous buck converter family
Wide input voltage range of 3.5V to 65V
4A, 6A, and 8A output current options
Adjustable output voltage from 0.8V to 60V, or fixed output options of 3.3V and 5V
150°C maximum junction temperature
36ns t
ON(min)
for high step-down conversion
Mitigated interference and noise technology – architecture 1 (MINT 1)
Facilitates
CISPR 11 or 32 Class B
compliance
Enhanced
HotRod™
QFN (eQFN) package with symmetrical pinout design and minimal L
LOOP
Spread Spectrum (
DRSS
) and switching slew-rate control reduce peak emissions
Switching frequency from 300kHz to 2.2MHz
High efficiency across the full load current range
95% at 48V
IN
, 12V
OUT
, 8A, 400kHz
Multiphase stackable for higher output current
Dual-input VCC subregulator with BIAS option
VIN sleep quiescent current as low as 1.8µA
Improved reliability with optimized
pinout design
and clearance for short-circuit-to-adjacent-pin test
VIN to PGND pin clearance of 1.1mm
Create a custom design using the
LM656x0
with the
WEBENCH® Power Designer