ISL6440 Intersil Corporation, ISL6440 Datasheet - Page 14

• Manufacturer Part Number: ISL6440
• Description: Step-Down PWM Controller
• Manufacturer: Intersil Corporation

value as shown. The combined out-of-phase current is the
square root of the sum of the square of the individual
reflected currents and is significantly less than the combined
in-phase current.
Use a mix of input bypass capacitors to control the voltage
ripple across the MOSFETs. Use ceramic capacitors for the
high frequency decoupling and bulk capacitors to supply the
RMS current. Small ceramic capacitors can be placed very
close to the upper MOSFET to suppress the voltage induced
in the parasitic circuit impedances.
For board designs that allow through-hole components, the
Sanyo OS-CON® series offer low ESR and good
temperature performance. For surface mount designs, solid
tantalum capacitors can be used, but caution must be
exercised with regard to the capacitor surge current rating.
These capacitors must be capable of handling the surge-
current at power-up. The TPS series available from AVX is
surge current tested.
4.5
3.5
2.5
1.5
0.5
5
4
3
2
1
0
0
FIGURE 17. INPUT RMS CURRENT vs LOAD
OUT OF PHASE
1
3.3V AND 5V LOAD CURRENT
IN PHASE
2
14
3
3.3V
4
5V
5
ISL6440
October 4, 2005
FN9040.2