PRODUCT DATASHEET
AAT2688
SystemPower
TM
4.5A PMIC Solution for 12V Adapter Systems with 2-Output High Performance Step-Down Converters
General Description
The AAT2688 provides two independently regulated DC
outputs: a high voltage synchronous step-down (Buck)
regulator and a low input voltage step-down low dropout
(LDO) regulator. The PMIC is optimized for low cost 12V
adapter inputs, making the device the ideal system-on-
a-chip power solution for consumer communications
equipment.
Channel 1 is a step-down regulator with an input voltage
range of 6.0V to 24V, providing up to 4.5A output cur-
rent. 490kHz fixed switching frequency allows small L/C
filtering components. Channel 1 utilizes voltage mode
control configured for optimum performance across the
entire output voltage and load range.
Channel 2 is a low-dropout (LDO) regulator providing up
to 600mA output current. The device provides low out-
put noise, low quiescent current, and excellent transient
response.
The step-down regulator includes integrated over-cur-
rent, soft-start and over-temperature protection. Inde-
pendent input and enable pins provide maximum design
flexibility.
The AAT2688 is available in the Pb-free 4mm x 5mm
24-pin TQFN package. The rated operating temperature
range is -40°C to 85°C.
Features
• 2-Output Step-Down Converters:
• Channel 1 (Buck): V
IN1
= 6.0 to 24.0V
▪
V
OUT1
Adjustable from 0.8V to 5.5V
▪
I
OUT1
up to 4.5A
▪
High Switching Frequency
▪
Voltage Mode Control
▪
High Accuracy ±1.5%
▪
PWM Fixed Frequency for Low Ripple
• Channel 2 (LDO): V
IN2
= 2.7V to 5.5V
▪
I
OUT2
up to 600mA
▪
1V Dropout Voltage at 600mA I
OUT
• Small Solution Size
• System on a Chip
• Ultra-small External L/C
• Shutdown Current <35μA
• Independent Enable Pins
• Over-Current and Over-Temperature Protection
• Internal Soft Start
• 4x5mm 24-Pin TQFN Low Profile Package
• -40°C to 85°C Temperature Range
Applications
•
•
•
•
DSL and Cable Modems
Notebook Computers
Satellite Set-top Boxes
Wireless LAN Systems
Typical Application
L1 4.7μH/5.3A
C3
0.1μF
D1
BAS16
J1
V
IN1
6.0V -24.0V
2
1
V
OUT1
3.3V/4.5A
LX1
BST1
VL1
DL
Q1
R2
2K
RS1
OS1
IN1
FB1
COMP1
R1
3.92k
C5
2.2nF
C6
150pF
OUT2
C12
2.2μF
V
OUT2
R4
1.96k
R5
150
C4
220nF
C10
2.2nF
R3
9.09k
C14
2.2μF
C7
22μF
C8
22μF
C9
22μF
AAT2688
EN1
V
IN2
+
C1
220μF
25V
C13
1μF
25V
C2
2.2μF
IN2
EN2
GND
TQFN45-24
2688.2008.06.1.0
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