High Current Path With Bottom Mosfet(S) Turned On; General Layout Recommendations; High Current Path With Top And Bottom Mosfets Turned Off (Dead Time) - Intel Pentium M Processor Design Manual

Dead Time there is a high current flow through the inductor, processor, ground, and the Schottky
diode. The diode and its traces must be laid out in such as to minimize both stray inductance and
resistance with short, fat traces or planes.
Figure 134.

High Current Path With Top and Bottom MOSFETs Turned Off (Dead Time)

11.3.7.4

High Current Path With Bottom MOSFET(s) Turned ON

A few nanoseconds after the top MOSFET is turned OFF, the bottom MOSFET(s) is turned ON.
The high current path now switches from the Schottky diode to the bottom MOSFET(s), the current
path shown by the dashed/arrow line in
short, fat traces or planes.
Figure 135.

High Current Path With Bottom MOSFET(s) Turned ON

11.3.7.5

General Layout Recommendations

All or the components in the high current paths dissipate some power (i.e., they get warm when
current runs through them). To minimize temperature rise and facilitate thermal spreading, large
copper fill areas connecting the high current components is imperative. For example, the MOSFET
manufacturers recommend that each MOSFET be mounted on one square inch of two-ounce
copper. While this may not be possible in all environments, this recommendation serves to
illustrate the importance of thermal considerations in the switching regulator layout.
Design Guide
® ®
Intel Pentium M Processor and Intel
Voltage
Regulator
Control Circuitry
Figure
Voltage
Regulator
Control Circuitry
®
E7501 Chipset Platform
Platform Power Delivery Guidelines
135. Minimize stray inductance and resistance with
199