ZHCSNB4 february 2023 LM5148
PRODUCTION DATA
- 1 特性
- 2 應用
- 3 說明
- 4 Revision History
- 5 說明（續(xù)）
- 6 Pin Configuration and Functions
- 7 Specifications
-
8 Detailed Description
- 8.1 Overview
- 8.2 Functional Block Diagram
- 8.3
Feature Description
- 8.3.1 Input Voltage Range (VIN)
- 8.3.2 High-Voltage Bias Supply Regulator (VCC, VCCX, VDDA)
- 8.3.3 Precision Enable (EN)
- 8.3.4 Power-Good Monitor (PG)
- 8.3.5 Switching Frequency (RT)
- 8.3.6 Dual Random Spread Spectrum (DRSS)
- 8.3.7 Soft Start
- 8.3.8 Output Voltage Setpoint (FB)
- 8.3.9 Minimum Controllable On Time
- 8.3.10 Error Amplifier and PWM Comparator (FB, EXTCOMP)
- 8.3.11 Slope Compensation
- 8.3.12 Inductor Current Sense (ISNS+, VOUT)
- 8.3.13 Hiccup Mode Current Limiting
- 8.3.14 High-Side and Low-Side Gate Drivers (HO, LO)
- 8.3.15 Output Configurations (CNFG)
- 8.3.16 Single-Output Dual-Phase Operation
- 8.4 Device Functional Modes
-
9 Application and Implementation
- 9.1 Application Information
- 9.2
Typical Applications
- 9.2.1
Design 1 – High Efficiency 2.1-MHz Synchronous
Buck Regulator
- 9.2.1.1 Design Requirements
- 9.2.1.2
Detailed Design Procedure
- 9.2.1.2.1 Custom Design with WEBENCH? Tools
- 9.2.1.2.2 Custom Design with Excel Quickstart Tool
- 9.2.1.2.3 Buck Inductor
- 9.2.1.2.4 Current-Sense Resistance
- 9.2.1.2.5 Output Capacitors
- 9.2.1.2.6 Input Capacitors
- 9.2.1.2.7 Frequency Set Resistor
- 9.2.1.2.8 Feedback Resistors
- 9.2.1.2.9 Compensation Components
- 9.2.1.3 Application Curves
- 9.2.2 Design 2 – High Efficiency 48-V to 12-V 400-kHz Synchronous Buck Regulator
- 9.2.3 Design 3 – High Efficiency 440-kHz Synchronous Buck Regulator
- 9.2.4 Design 4 – Dual-Phase 400-kHz 20-A Synchronous Buck Regulator
- 9.2.1
Design 1 – High Efficiency 2.1-MHz Synchronous
Buck Regulator
- 9.3 Power Supply Recommendations
- 9.4 Layout
- 10Device and Documentation Support
- 11Mechanical, Packaging, and Orderable Information
封裝選項
機械數(shù)據(jù) (封裝 | 引腳)
- RGY|24
散熱焊盤機械數(shù)據(jù) (封裝 | 引腳)
- RGY|24
訂購信息
9.2.1.2.3 Buck Inductor
- Use Equation 31 to calculate the required buck inductance based on a 30% ΔILO inductor
ripple current at nominal input voltages. Equation 31.
- Select a standard inductor value of 0.56 μH or
use a 0.68 μH to account for effective inductance derating over the current range of
molded inductors. Use Equation 32 to calculate the peak inductor currents at maximum steady-state input voltage.
Subharmonic oscillation occurs with a duty cycle greater than 50% for peak current-mode
control. For design simplification, the LM5148 has an internal slope compensation ramp proportional to the switching
frequency that is added to the current sense signal to damp any tendency toward
subharmonic oscillation. Equation 32.
- Based on Equation 9, use Equation 33 to cross-check the inductance to set a slope compensation close to the ideal one times
the inductor current downslope.Equation 33.
