ZHCSIJ1E June 1999 – July 2018 LM2574 , LM2574HV
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 5 Pin Configuration and Functions
-
6 Specifications
- 6.1 Absolute Maximum Ratings
- 6.2 ESD Ratings
- 6.3 Recommended Operating Conditions
- 6.4 Thermal Information
- 6.5 Electrical Characteristics for All Output Voltage Versions
- 6.6 Electrical Characteristics – 3.3-V Version
- 6.7 Electrical Characteristics – 5-V Version
- 6.8 Electrical Characteristics – 12-V Version
- 6.9 Electrical Characteristics – 15-V Version
- 6.10 Electrical Characteristics – Adjustable Version
- 6.11 Typical Characteristics
- 7 Detailed Description
-
8 Application and Implementation
- 8.1 Application Information
- 8.2 Typical Applications
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機械、封裝和可訂購信息
8.2.2.2.3 Output Capacitor Selection (COUT)
The value of the output capacitor together with the inductor defines the dominate pole-pair of the switching regulator loop. For stable operation, the capacitor must satisfy the requirement in Equation 13.
Equation 13 yields capacitor values between 5 μF and 1000 μF that satisfies the loop requirements for stable operation. But to achieve an acceptable output ripple voltage, (approximately 1% of the output voltage) and transient response, the output capacitor may need to be several times larger than the above formula yields.
The voltage rating of the capacitor must be at last 1.5 times greater than the output voltage. For a 24-V regulator, a rating of at least 35 V is recommended. Higher voltage electrolytic capacitors generally have lower ESR numbers, and for this reasion it may be necessary to select a capacitor rate for a higher voltage than would normally be needed.
However, for acceptable output ripple voltage select:
COUT ≥ 100 μF
COUT = 100 μF electrolytic capacitor