ZHCSKX8B September 2019 – September 2020 LMR36503-Q1
PRODUCTION DATA
- 1 特性
- 2 應用
- 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 Enable, Start-up and Shutdown
- 8.3.2 External CLK SYNC (with MODE/SYNC)
- 8.3.3 Adjustable Switching Frequency (with RT)
- 8.3.4 Power-Good Output Operation
- 8.3.5 Internal LDO, VCC UVLO, and VOUT/BIAS Input
- 8.3.6 Bootstrap Voltage and VCBOOT-UVLO (CBOOT Terminal)
- 8.3.7 Output Voltage Selection
- 8.3.8 Soft Start and Recovery from Dropout
- 8.3.9 Current Limit and Short Circuit
- 8.3.10 Thermal Shutdown
- 8.3.11 Input Supply Current
- 8.4 Device Functional Modes
-
9 Application and Implementation
- 9.1 Application Information
- 9.2
Typical Application
- 9.2.1 Design Requirements
- 9.2.2 Detailed Design Procedure
- 9.2.3 Application Curves
- 9.3 What to Do and What Not to Do
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Mechanical, Packaging, and Orderable Information
9.2.2.8.1 External UVLO
In some cases, an input UVLO level different than that provided internal to the device is needed. This can be accomplished by using the circuit shown in Figure 9-2. The input voltage at which the device turns on is designated as VON while the turnoff voltage is VOFF. First, a value for RENB is chosen in the range of 10 kΩ to 100 kΩ, then Equation 11 is used to calculate RENT and VOFF.
Figure 9-2 Setup for External UVLO ApplicationEquation 11. 
where
- VON is the VIN turnon voltage.
- VOFF is the VIN turnoff voltage.