ISL6556ACBZ-T Intersil, ISL6556ACBZ-T Datasheet - Page 22

• Manufacturer Part Number: ISL6556ACBZ-T
• Description: IC CTRLR MULTIPHASE VRM10 28SOIC
• Manufacturer: Intersil

Specifications of ISL6556ACBZ-T

• Applications: Controller, Intel VR10X
• Voltage - Input: 3 ~ 12 V
• Number Of Outputs: 4
• Voltage - Output: 0.84 ~ 1.6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

MULTI-PHASE RMS IMPROVEMENT
Figure 17 is provided as a reference to demonstrate the
dramatic reductions in input-capacitor RMS current upon the
implementation of the multi-phase topology. For example,
compare the input RMS current requirements of a two-phase
converter versus that of a single phase. Assume both
converters have a duty cycle of 0.25, maximum sustained
output current of 40A, and a ratio of I
single phase converter would require 17.3 Arms current
capacity while the two-phase converter would only require
10.9 Arms. The advantages become even more pronounced
when output current is increased and additional phases are
added to keep the component cost down relative to the
single phase approach.
FIGURE 17. NORMALIZED INPUT-CAPACITOR RMS
FIGURE 16. NORMALIZED INPUT-CAPACITOR RMS CURRENT
0.3
0.2
0.1
0.6
0.4
0.2
0
0
0
0
I
I
L,PP
L,PP
= 0
= 0.25 I
vs DUTY CYCLE FOR 4-PHASE CONVERTER
I
I
I
CURRENT vs DUTY CYCLE FOR SINGLE-PHASE
CONVERTER
L,PP
L,PP
L,PP
0.2
0.2
= 0
= 0.5 I
= 0.75 I
O
DUTY CYCLE (V
DUTY CYCLE (V
O
O
0.4
0.4
22
I
I
L,PP
L,PP
= 0.5 I
= 0.75 I
0.6
0.6
O
O
C,PP
/V
/V
IN
IN
O
)
)
O
to I
O
0.8
0.8
of 0.5. The
1.0
1.0
ISL6556A
Layout Considerations
The following layout strategies are intended to minimize the
impact of board parasitic impedances on converter
performance and to optimize the heat-dissipating capabilities
of the printed-circuit board. These sections highlight some
important practices which should not be overlooked during the
layout process.