PRODUCT DATASHEET
AAT1
189
SwitchReg
TM
Pin Descriptions
Pin #
1, 2, 3, 4, 5,
15, 16
6
7
8
9
10
11
12
13
14
EP
High Voltage Step-Down Regulator
Symbol
LX
BST
EN
RS
OS
COMP
FB
GND
VL
IN
IN
Function
Step-down converter switching pin. Connect output inductor to this pin. Connect LX pins together.
Boost drive input pin. Connect the cathode of fast rectifier from this pin and connect a 100nF ca-
pacitor from this pin to the switching node (LX) for internal hi-side MOSFET gate drive.
Enable input pin. Active high.
Output current sense pin. Connect a small signal resistor from this pin to switching node (LX) to en-
able over-current sense for step-down converter.
Output voltage sense pin. Connect to the output capacitor to enable over-current sense for step-
down converter.
Compensation pin for step-down regulator. Connect a series resistor, capacitor network to compen-
sate the voltage mode control loop.
Feedback input pin for step-down converter. Connect an external resistor divider to this pin to pro-
gram the output voltage to the desired value.
Ground pin for step-down converter. Connect input and output capacitors return terminals close to
this pin for best noise performance.
Internal linear regulator. Connect a 2.2μF/6.3V capacitor from this pin to GND pin.
Input supply voltage pin for step-down regulator. Connect both IN pins together. Connect the input
capacitor close to this pin for best noise performance.
Exposed paddle connected internally to IN. Connect to PCB heatsink to ensure maximum thermal
dissipation.
Pin Configuration
TDFN34-16
(Top View)
LX
LX
LX
LX
LX
BST
EN
RS
1
2
3
4
5
6
7
8
16
15
14
EP
13
12
11
10
9
LX
LX
IN
VL
GND
FB
COMP
OS
2
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1189.2008.06.1.0
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