LTC3826 Linear Technology, LTC3826 Datasheet - Page 15

• Manufacturer Part Number: LTC3826
• Description: 2-Phase Synchronous Step-Down Controller
• Manufacturer: Linear Technology

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OPERATION
path, which could include batteries, switches, trace/con-
nector resistances and protection circuitry. Improvements
in both conducted and radiated EMI also directly accrue as
a result of the reduced RMS input current and voltage.
Of course, the improvement afforded by 2-phase opera-
tion is a function of the dual switching regulator’s relative
duty cycles which, in turn, are dependent upon the input
voltage V
the RMS input current varies for single-phase and 2-phase
operation for 3.3V and 5V regulators over a wide input
voltage range.
IN
(Duty Cycle = V
(Refer to Functional Diagram)
OUT
/V
IN
). Figure 2 shows how
Figure 2. RMS Input Current Comparison
3.0
2.5
2.0
1.5
1.0
0.5
0
0
V
V
01
02
= 5V/3A
= 3.3V/3A
10
INPUT VOLTAGE (V)
DUAL CONTROLLER
SINGLE PHASE
DUAL CONTROLLER
2-PHASE
20
It can readily be seen that the advantages of 2-phase op-
eration are not just limited to a narrow operating range,
for most applications is that 2-phase operation will reduce
the input capacitor requirement to that for just one channel
operating at maximum current and 50% duty cycle.
The schematic on the fi rst page is a basic LTC3826 ap-
plication circuit. External component selection is driven
by the load requirement, and begins with the selection of
R
are selected. Finally, C
SENSE
30
and the inductor value. Next, the power MOSFETs
3826 F02
40
IN
and C
OUT
are selected.
LTC3826
15
3826fc