ZHCSKX8B September 2019 – September 2020 LMR36503-Q1
PRODUCTION DATA
- 1 特性
- 2 應(yīng)用
- 3 說(shuō)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
封裝選項(xiàng)
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- RPE|9
散熱焊盤(pán)機(jī)械數(shù)據(jù) (封裝 | 引腳)
- RPE|9
訂購(gòu)信息
8.3.11 Input Supply Current
The LMR36503-Q1 is designed to have very low input supply current when regulating light loads. This is achieved by powering much of the internal circuitry from the output. The VOUT/BIAS pin in the fixed-output voltage variants is the input to the LDO that powers the majority of the control circuits. By connecting the VOUT/BIAS input pin to the output node of the regulator, a small amount of current is drawn from the output. This current is reduced at the input by the ratio of VOUT / VIN.
Equation 3. 
where
- IQ_VIN is the total standby (switching) current consumed by the operating (switching) buck converter when unloaded.
- IQ is the current drawn from the VIN terminal. Check IQ_13p5_Fixed or IQ_24p0_Fixed in Section 7.5 for IQ.
- IEN is current drawn by the EN terminal. Include this current if EN is connected to VIN. Check ILKG-EN in Section 7.5 for IEN.
- IBIAS is bias current drawn by the BIAS input. Check IB_13p5 or IB_24p0 in Section 7.5 for IBIAS.
- ηeff is the light-load efficiency of the buck converter with IQ_VIN removed from the input current of the buck converter. ηeff = 0.8 is a conservative value that can be used under normal operating conditions. This can be traced back as the ISUPPLY in Section 7.7.