AAT1157 AAT, AAT1157 Datasheet - Page 2

• Manufacturer Part Number: AAT1157
• Description: DC/DC Converter
• Manufacturer: AAT

Pin Descriptions
Pin Configuration
2
13, 14, 15
10, 11, 12
6, 8, 16
1, 2, 3
Pin #
EP
4
5
7
9
Symbol
PGND
SGND
VCC
N/C
EN
FB
VP
LX
Main power ground return pin. Connect to the output and input capacitor
return. (See board layout rules.)
Feedback input pin. This pin is connected to the converter output. It is used to
set the output of the converter to regulate to the desired value via an internal
resistive divider. For an adjustable output, an external resistive divider is con-
nected to this pin.
Signal ground. Connect the return of all small signal components to this pin.
(See board layout rules.)
Enable input pin. A logic high enables the converter; a logic low forces the
AAT1157 into shutdown mode reducing the supply current to less than 1µA.
The pin should not be left floating.
Bias supply. Supplies power for the internal circuitry. Connect to input power
via low pass filter with decoupling to SGND.
Input supply voltage for the converter power stage. Must be closely decoupled
to PGND.
Connect inductor to these pins. Switching node internally connected to the
drain of both high- and low-side MOSFETs.
Function
Not internally connected.
Exposed paddle (bottom); connect to PGND directly beneath package.
PGND
PGND
PGND
FB
1
2
3
4
(Top View)
QFN33-16
1MHz 1.2A Buck DC/DC Converter
12
11
10
9
VP
VP
VP
VCC
AAT1157
1157.2005.11.1.4