CS5166

http://onsemi.com

20

COMP

GATE(H)

GATE(L)

PWRGD

PGND

SS

3.0 mΩ

330 pF

LGND

1.2 μH

0.1 μF

3.3 k

0.1 μF

1000 pF

12 V

1200 μF/

10 V × 5

2.8 V/30 A

Power Supply

1.0 μF

IRL3103S

0.1 μF

PWRGD

IRL3103S

1200 μF/10 V × 3

5.0 V

0.1 μF

510

510

COMP

GATE(H)

GATE(L)

PGND

SS

LGND

12 V

5.0 V

1200 μF/

10 V × 3

3.0 mΩ

1.0 μF

330 pF

3.3 k

0.1 μF

1.2 μH

IRL3103S

IRL3103S

1000 pF

Figure 31. Current Sharing of a 2.8 V/30 A Power Supply Using Two CS5166 Synchronous Buck Regulators

Droop Resistor Width Calculations

The droop resistor must have the ability to handle the load

current and therefore requires a minimum width which is

calculated as follows (assume one ounce copper thickness):

W +

ILOAD

0.05

where:

W = minimum width (in mils) required for proper power

The Pentium II maximum load current is 14.2 A.

Therefore:

W + 14.2 A

0.05 +

284 mils + 0.7213 cm

Droop Resistor Length Calculation

L +

RDROOP

W

t

ò

+ 0.0030

284

1.37

717.86

+ 1626 mil + 4.13 cm