ZHCSKV1A February 2020 – July 2020 LM76005
PRODUCTION DATA
The LM76005 device requires an input decoupling and, depending on the application, a bulk input capacitor. The typical recommended value for the high frequency decoupling capacitor is 10 μF to 22 μF. TI recommends a high-quality ceramic type X5R or X7R with sufficiency voltage rating. The voltage rating must be greater than the maximum input voltage. To compensate the derating of ceramic capacitors, a voltage rating of twice the maximum input voltage is recommended.
Many times, it is desirable and necessary to use an electrolytic capacitor on the input in parallel with the ceramics. This is especially true if the LM76005 circuit is not located within approximately 5 cm from the input voltage source. This capacitor can help damp any ringing on the input supply caused by the long power leads and the associated inductance. The use of this additional capacitor also helps with momentary voltage dips caused by input supplies with unusually high impedance. The optimum value for this capacitor is four times the ceramic input capacitance with ESR close to the characteristic impedance of the LC filter formed by the application input inductance and ceramic input capacitors.
For this design, two 4.7-μF, X7R dielectric capacitors rated for 100 V are used for the input decoupling capacitance. A single capacitor can aslo be used that has an equivalent series resistance (ESR) of approximately 3 mΩ, and an RMS current rating of 5 A. Include a capacitor with a value of 47 nF for high-frequency filtering and place it as close as possible to the device pins.
DC-Bias Effect: High capacitance ceramic capacitors have a DC-bias derating effect, which has a strong influence on the final effective capacitance. Therefore, choose the right capacitor value carefully. Package size and voltage rating in combination with dielectric material are responsible for differences between the rated capacitor value and the effective capacitance.