AATIAN26 Datasheet, PDF (1/4 Pages) SiGe Semiconductor, Inc. – 850kHz 1A Buck Regulator

EV-103
AAT1152 EVAL
850kHz 1A Buck Regulator
Introduction
The AAT1152 MSOP evaluation board demonstrates performance, along with the suggested size and place-
ment of external components, for the AAT1152 integrated buck regulator. The external components are select-
ed for minimum size and optimum operation up to 1A output current. Please refer to the AAT1152 datasheet
for more details about this product.
Layout
As with all switching power supplies, board layout for the AAT1152 is critical (see Figure 1). Special care has
been taken with the placement of the external components. The input capacitor (C1) placement is critical and
it must be located immediately adjacent to the AAT1152. As shown in Figure 2, the LX node trace has been
routed under C1 in order to facilitate placement of C1 close to the IC. The output voltage feedback trace has
been routed on the portion of backside of the board which has a ground plane on the top side (see Figure 3).
The trace is routed to avoid the LX node and associated noise. Please refer to Table 1 for AAT1152 evalua-
tion board specifications.
V_IN+
C1
10µF
R1 100
R2
100k
C2
0.1µF
EN
R5
100k
POK
U1
AAT1152
5
VP
1
FB
4
7
VCC POK
3
EN
6
LX
2
8
SGND PGND
V_O-
R3
V_O+
R4
10k 1%
L1
4.1µH
C3-C5
3x 22µF
6.3V X5R
Figure 1: AAT1152 Evaluation Board Schematic.
Specification
Input Voltage
Output Error Voltage
Output Current
Test Conditions
Min
Typ
2.7
3.6
±3
0
Table 1: AAT1152 Evaluation Board Specification.
Max
5.5
1.0
Units
V
%
A
EV-103.2005.07.1.1
1