PRODUCT DATASHEET
AAT2113A
TM
SwitchReg
3MHz, FastTransient 1.5A Step-Down Converter in 2mm x 2mm Package
Since RDS(ON), quiescent current, and switching losses all
vary with input voltage, the total losses should be inves-
tigated over the complete input voltage range.
3. For the fixed version, the feedback trace or FB pin
should be separated from any power trace and con-
nected as closely as possible to the load point.
Sensing along a high-current load trace will degrade
DC load regulation. For the adjustable version, the
trace connecting the FB pin to resistors R1 and R2
should be as short as possible by placing R1 and R2
immediately next to the AAT2113A. The sense trace
connection from R1 to the output voltage should be
separate from any power trace and connect as
closely as possible to the load point. The external
feed-forward capacitor C2 should be connected as
close as possible in parallel with R1 for enhanced
transient response.
Given the total losses, the maximum junction tempera-
ture can be derived from the θJA for the FTDFN22-8
package, which is 70°C/W.
TJ(MAX) = PTOTAL · ΘJA + TAMB
PCB Layout Considerations
The suggested PCB layout for the AAT2113A is shown in
Figures 3 and 4 (fixed version) or Figures 6 and 7 (adjust-
able version). The following guidelines should be used to
help ensure a proper layout:
4. The resistance of the trace from the load return to
PGND should be kept to a minimum. This will help to
minimize any error in DC regulation due to differ-
ences in the potential of the internal signal ground
and the power ground.
1. The input capacitor (C1) should be connected as
close as possible to VP and PGND.
2. The output capacitor and L1 should be connected as
closely as possible. The connection of L1 to the LX
pin should be as short as possible.
5. Connect unused signal pins to ground to avoid
unwanted noise coupling.
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