AATIAN24 Datasheet, PDF (1/4 Pages) SiGe Semiconductor, Inc. – 850kHz 700mA Buck Regulator

EV-108
AAT1151 MSOP EVAL
850kHz 700mA Buck Regulator
Introduction
The AAT1151 MSOP evaluation board demonstrates performance, along with the suggested size and place-
ment of external components, for the AAT1151 integrated buck regulator. The external components are select-
ed for minimum size and optimum operation up to 700mA output current. The output voltage can be adjusted
with the use of the 1.0V version of the AAT1151 and external resistors R3 and R4. Please refer to the AAT1151
product datasheet for more details about this product.
Layout
As with all switching power supplies, the board layout for the AAT1151 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 AAT1151. 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 the back side 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 see Table 1 for AAT1151
MSOP evaluation board specifications.
V_IN+
Enable
C1
10µF
R1 100
R2
100k _C7
0.1µF
LX
AAT1151IKS
5 _VP
FB ¹
4 _VCC
LX ⁷
3 _EN
LX ⁶
2 _{GND PGND} 8
R4
10.0k
V_OUT+
R3
L1
3.3µH
C2-C6
GND
GND
Figure 1: AAT1151 MSOP Evaluation Board Schematic.
Specification
Input Voltage
Output Error Voltage
Output Current
Test Conditions
Min
Typ
2.7
3.6
-3
0
Table 1: AAT1151 MSOP Evaluation Board Specifications.
Max
5.5
+3
700
Units
V
%
mA
EV-108.2005.01.1.0
1