TLF50241EL_15 Datasheet, PDF (27/30 Pages) Marl International Limited – 2.2 MHz Step-Down Regulator 500 mA, 5 V, low quiescent current

TLF50241EL
Application Information
Conducted disturbances:
Conducted disturbances are voltage spikes or voltage oscillations, occurring permanently or by occasion mostly
on the input or output connections. Comparable to the radiated electric fields they are caused by voltage stage,
freewheeling diode D_CATCH, and output capacitor C_OUT.
Their frequencies might be above 100 MHz. They are super positioned to the input and output voltage and might
therefore disturb other components of the application.
The countermeasures against conducted disturbances are similar to the radiated electric fields:
• it is recommended to use short and thick connections between the single parts of the converter;
• all parts shall be mounted close together;
• additional filter capacitors (ceramic, with low ESR i.e C_IN3 in the application diagram) in parallel to the output
and input capacitor and as close as possible to the switching parts. Input and load current must be forced to
pass these devices, do not connect them via thin lines. Recommended values from 10nF to 220nF;
• for the input filter a so called π – Filter for maximum suppression might be necessary, which requires additional
capacitors on the input.
9.1.1 Additional information
Please contact us:
• for information regarding the Pin FMEA;
• for existing application notes with more detailed information about the possibilities of this device;
• for further information you may contact http://www.infineon.com/
Data Sheet
27
Rev. 1.0, 2013-06-19