ZHCSMV4A December 2020 – December 2022 TPS548B28
PRODUCTION DATA
- 1 特性
- 2 應(yīng)用
- 3 說(shuō)明
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Internal VCC LDO And Using External Bias On VCC Pin
- 7.3.2 Enable
- 7.3.3 Output Voltage Setting
- 7.3.4 Internal Fixed Soft Start and External Adjustable Soft Start
- 7.3.5 External REFIN For Output Voltage Tracking
- 7.3.6 Frequency and Operation Mode Selection
- 7.3.7 D-CAP3? Control Mode
- 7.3.8 Low-side FET Zero-Crossing
- 7.3.9 Current Sense and Positive Overcurrent Protection
- 7.3.10 Low-side FET Negative Current Limit
- 7.3.11 Power Good
- 7.3.12 Overvoltage and Undervoltage Protection
- 7.3.13 Out-Of-Bounds (OOB) Operation
- 7.3.14 Output Voltage Discharge
- 7.3.15 UVLO Protection
- 7.3.16 Thermal Shutdown
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Output Voltage Setting Point
- 8.2.2.2 Choose the Switching Frequency and the Operation Mode
- 8.2.2.3 Choose the Inductor
- 8.2.2.4 Set the Current Limit (TRIP)
- 8.2.2.5 Choose the Output Capacitor
- 8.2.2.6 Choose the Input Capacitors (CIN)
- 8.2.2.7 Soft Start Capacitor (SS/REFIN Pin)
- 8.2.2.8 EN Pin Resistor Divider
- 8.2.2.9 VCC Bypass Capacitor
- 8.2.2.10 BOOT Capacitor
- 8.2.2.11 PGOOD Pullup Resistor
- 8.2.3 Application Curves
- 8.3 Power Supply Recommendations
- 8.4 Layout
- 9 Device and Documentation Support
- 10Mechanical, Packaging, and Orderable Information
封裝選項(xiàng)
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- RWW|21
散熱焊盤(pán)機(jī)械數(shù)據(jù) (封裝 | 引腳)
訂購(gòu)信息
8.2.2.6 Choose the Input Capacitors (CIN)
The device requires input bypass capacitors between the VIN and PGND pins to bypass the power-stage. The bypass capacitors must be placed as close as possible to the pins of the IC as the layout will allow. At least 10 μF of ceramic capacitance and 1-μF high frequency ceramic bypass capacitors are required. A 1-μF, 16-V X6S size 0402 ceramic capacitor on VIN pin 10 and pin 21 is required. A 1-μF 16-V X6S ceramic capacitor on the bottom layer is recommended for high current applications. The high frequency bypass capacitor minimizes high frequency voltage overshoot across the power-stage. The ceramic capacitors must be a high-quality dielectric of X6S or better for their high capacitance-to-volume ratio and stable characteristics across temperature. In addition to this, more bulk capacitance can be needed on the input depending on the application to minimize variations on the input voltage during transient conditions.
The input capacitance required to meet a specific input ripple target can be calculated with Equation 25. A recommended target input voltage ripple is 5% the minimum input voltage, which is 400 mV in this example. The calculated input capacitance needed is 6.84 μF and four 22-μF ceramic capacitors are recommended for this example.
The capacitor must also have an RMS current rating greater than the maximum input RMS current in the application. The input RMS current the input capacitors must support is calculated by Equation 26 and is 6.625 A in this example. The ceramic input capacitors have a current rating greater than this.
For applications requiring bulk capacitance on the input, such as ones with low input voltage and high current, the selection process in this article is recommended.