ZHCSS74B january 2015 – june 2023 LV2862
PRODUCTION DATA
- 1
- 1 特性
- 2 應用
- 3 說明
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Detailed Description
- 8 Application and Implementation
- 9 Device and Documentation Support
- 10Mechanical, Packaging, and Orderable Information
8.2.2.5 Input Capacitor Selection
A low ESR ceramic capacitor is needed between the VIN pin and ground pin. This capacitor prevents large voltage transients from appearing at the input. Use a 2.2 μF–10 μF value with X5R or X7R dielectric. Depending on construction, the value of a ceramic capacitor can decrease up to 50% of its nominal value when rated voltage is applied. Consult with the capacitor manufacturer's data sheet for information on capacitor derating over voltage and temperature. The capacitor must also have a ripple current rating greater than the maximum input current ripple of the LV2862. The input ripple current can be calculated using Equation 10 and Equation 11.
For this example design, one 4.7-μF, 50-V capacitor is selected. The input capacitance value determines the input ripple voltage of the regulator. The input voltage ripple can be calculated using Equation 10. Using the design example values, Ioutmax = 0.6 A, Cin = 2.2 μF, and fsw = 770 kHz yields an input voltage ripple of 97 mV and an RMS input ripple current of 0.3 A.
