SNAS879 December 2024 LMR60420
PRODMIX
- 1
- 1 Features
- 2 Applications
- 3 Description
- 4 Device Comparison Table
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Detailed Description
-
8 Application and
Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2 Detailed Design Procedure
- 8.2.3 Application Curves
- 8.3 Power Supply Recommendations
- 8.4 Layout
- 9 Device and Documentation Support
- 10Revision History
- 11Mechanical, Packaging, and Orderable Information
封裝選項(xiàng)
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- RAK|9
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
訂購(gòu)信息
7.3.1 Enable and Undervoltage Lockout (UVLO)
LMR60420 features a precision enable and undervoltage lockout (UVLO) feature which enables the user to select the voltage level at which the device powers on and off based on the voltage present at the EN pin. To power on the device the voltage between EN pin and PGND pin must exceed the enable voltage rising threshold VEN-TH(R) (1.25V typical). After VEN-TH(R) has been crossed, and the minimum supply voltage, VINUVLO(R), have both been satisfied, the part begins the soft-start sequence described in Section 7.3.2.
The EN pin can be used to power down the device by reducing the voltage between the EN pin and PGND pin below the enable input low threshold VEN-TH(F) 1V (typical).
A resistor divider between VIN and PGND with the center point connected to the EN pin can be used to implement the VIN UVLO. To begin, select the input voltage at which the device turns off, choose the value of RENT, then calculate the required RENB. After RENB has been calculated, the resulting turn-on input voltage can be calculated. See Figure 7-1, Equation 1, and Equation 2 to determine the EN resistors required. If the VIN UVLO feature is not needed, the EN pin can be connected directly to VIN.
Where:
- VINturn-off represents the input voltage at which the LMR60420 turns off.
- VINturn-on represents the input voltage at which the LMR60420 turns on.
Figure 7-1 VIN UVLO Using the EN
Pin