Preliminary Datasheet

LP6270

LP6270QVF Version 1.0 Datasheet

NOV.-2013

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Page 5 of 6

Applications Information

The LP6270 uses a 1.2MHz fixed-frequency, current-mode regulation architecture to regulate the output voltage.

The LP6270 measures the output voltage through an external resistive voltage divider and compares that to the

internal 0.6V reference to generate the error voltage to the inductor current to regulate the output voltage. the use

of current-mode regulation improves transient response and control loop stability.

Current Limitation

The internal power-MOS switch current is monitored cycle-by-cycle and is limited to the value not exceed 2.6A

(Typ.). When the switch current reaches the limited value, the internal power-MOS is turned off immediately until

the next cycle. Keep traces at this pin as short as possible. Do not put capacitance at this pin.

Inductor Selection

For a better efficiency in high switching frequency converter, the inductor selection has to use a proper core

material such as ferrite core to reduce the core loss and choose low ESR wire to reduce copper loss. The most

important point is to prevent the core saturated when handling the maximum peak current. Using a shielded

inductor can minimize radiated noise in sensitive applications. The maximum peak inductor current is the

maximum input current plus the half of inductor ripple current. The calculated peak current has to be smaller than

the current limitation in the electrical characteristics. A typical setting of the inductor ripple current is 20% to 40% of

the maximum input current. If the selection is 40%, the maximum peak inductor current is

The minimum inductance value is derived from the following equation :

Depending on the application, the recommended inductor value is between 2.2μH to 10μH.