AAT1146 Analogic Corporation, AAT1146 Datasheet - Page 9

• Manufacturer Part Number: AAT1146
• Manufacturer: Analogic Corporation

Functional Block Diagram
Functional Description
The AAT1146 is a high performance 400mA
1.4MHz monolithic step-down converter. It has
been designed with the goal of minimizing external
component size and optimizing efficiency over the
complete load range. Apart from the small bypass
input capacitor, only a small L-C filter is required at
the output. Typically, a 4.7µH inductor and a 4.7µF
ceramic capacitor are recommended (see table of
values).
The fixed output version requires only three external
power components (C
adjustable version can be programmed with external
feedback to any voltage, ranging from 0.6V to the
1146.2006.01.1.2
EN
Note: For adjustable version, the internal feedback divider is omitted and the OUT pin is tied directly
to the internal error amplifier.
IN
, C
Reference
Voltage
INPUT
OUT
, and L). The
Amp
Err
See note
.
Fast Transient 400mA Step-Down Converter
OUT
input voltage. An additional feed-forward capacitor
can also be added to the external feedback to pro-
vide improved transient response (see Figure 1).
At dropout, the converter duty cycle increases to
100% and the output voltage tracks the input volt-
age minus the R
side MOSFET.
The input voltage range is 2.7V to 5.5V. The con-
verter efficiency has been optimized for all load
conditions, ranging from no load to 400mA.
The internal error amplifier and compensation pro-
vides excellent transient response, load, and line
regulation. Soft start eliminates any output voltage
overshoot when the enable or the input voltage is
applied.
Logic
DH
DL
DSON
VIN
drop of the P-channel high-
LX
PGND
AGND
AAT1146
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