RT8113 datasheet(20/21 Pages) RICHTEK

20 / 21 page

RT8113

DS8113-02 April 2011

www.richtek.com

The voltage feedback loop contains two traces, VCC

and VSS, which are Kelvin sensed from CPU socket or

output capacitors. These two traces should have 10mm

width and be placed away from high (di/dt) switching

elements such as high-side MOSFETs, low-side

MOSFETs, phase plane etc. The circuit elements of

voltage feedback loop, such as feedback loop short

resistors and voltage loop compensation RCs, have to

be kept near the RT8113 and also away from switching

elements.

The current-sense mechanism of the RT8113 is fully

differential Kelvin sense. Therefore, the current-sense

loop of the RT8113 contain two traces : the positive

trace(ISP) comes from the positive node the of output

inductor (the node connecting phase plane) and the

negative trace (ISN) comes from the negative node of

the output inductor (the node connecting output plane).

DO NOT connect the current-sense traces from the phase

plane or output plane. Only connect these traces from

both sides of the output inductor to achieve the goal of

precise Kelvin sense. The current-sense feedback loops

have to be routed away from switching elements, and the

current-sense RC elements have to be put near their

respective ISN or ISP pins of the RT8113 and also away

from noise switching elements. At lease 10 mm width is

suggested for current sense feedback loops.

RT8113 Datasheet(PDF) 20 Page - Richtek Technology Corporation