AAT1123IJS-1.2-T1 Advanced Analog Technology, Inc., AAT1123IJS-1.2-T1 Datasheet - Page 14

• Manufacturer Part Number: AAT1123IJS-1.2-T1
• Description: 1MHz Step-Down Converter
• Manufacturer: Advanced Analog Technology, Inc.

Since R
losses all vary with input voltage, the total losses
should be investigated over the complete input
voltage range.
Given the total losses, the maximum junction tem-
perature can be derived from the θ
SC70JW-8 package which is 160°C/W.
Layout
The suggested PCB layout for the AAT1123 is
shown in Figures 2, 3, and 4. The following guide-
lines should be used to help ensure a proper layout.
14
DS(ON)
T
J(MAX)
, quiescent current, and switching
= P
TOTAL
· Θ
JA
+ T
AMB
JA
for the
1. The input capacitor (C2) should connect as
2. C1 and L1 should be connected as closely as
3. The feedback trace or OUT pin (Pin 2) should
4. The resistance of the trace from the load return to
closely as possible to V
(Pins 6-8).
possible. The connection of L1 to the LX pin
should be as short as possible.
be separate from any power trace and connect
as closely as possible to the load point. Sensing
along a high-current load trace will degrade DC
load regulation. If external feedback resistors
are used, they should be placed as closely as
possible to the OUT pin (Pin 2) to minimize the
length of the high impedance feedback trace.
PGND (Pins 6-8) should be kept to a minimum.
This will help to minimize any error in DC regula-
tion due to differences in the potential of the inter-
nal signal ground and the power ground.
1MHz Step-Down Converter
IN
(Pin 3) and PGND
AAT1123
1123.2007.02.1.6