ZHCSQ27 October 2022 LM5012
PRODUCTION DATA
- 1 特性
- 2 應(yīng)用
- 3 說明
- 4 Revision History
- 5 Device Comparison Table
- 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 Control Architecture
- 8.3.2 Internal VCC Regulator and Bootstrap Capacitor
- 8.3.3 Regulation Comparator
- 8.3.4 Internal Soft Start
- 8.3.5 On-Time Generator
- 8.3.6 Current Limit
- 8.3.7 N-Channel Buck Switch and Driver
- 8.3.8 Schottky Diode Selection
- 8.3.9 Enable and Undervoltage Lockout (EN/UVLO)
- 8.3.10 Power Good (PGOOD)
- 8.3.11 Thermal Protection
- 8.4 Device Functional Modes
- 9 Application and Implementation
- 10Device and Documentation Support
- 11Mechanical, Packaging, and Orderable Information
封裝選項(xiàng)
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- DDA|8
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
- DDA|8
訂購信息
9.2.2.2 Switching Frequency (RRON)
The switching frequency of the LM5012 is set by the on-time programming resistor placed at RON. As shown by Equation 7, a standard 100-kΩ, 1% resistor sets the switching frequency at 300 kHz.
Note that at very low duty cycles, the 50-ns minimum controllable on time of the high-side MOSFET, tON(min), limits the maximum switching frequency. In CCM, tON(min) limits the voltage conversion step-down ratio for a given switching frequency. Use Equation 8 to calculate the minimum controllable duty cycle.
Ultimately, the choice of switching frequency for a given output voltage affects the available input voltage range, solution size, and efficiency. Use Equation 9 to calculate the maximum supply voltage for a given tON(min) before switching frequency reduction occurs.
