PRODUCT DATASHEET
AAT2689
SystemPower
TM
PMIC Solution for 12V Adapter Systems with 2-Output High Performance Step-Down Converters
General Description
The AAT2689 provides two independently regulated DC
outputs, consisting of a high voltage step-down (Buck)
regulator and a low input voltage low dropout (LDO) regu-
lator. 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 (Buck) regulator with an input
voltage range of 6V to 24V providing up to 2500mA out-
put current. 490kHz fixed switching frequency allows
small L/C filtering components. Channel 1 utilizes volt-
age 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 extremely
low output noise, low quiescent current and excellent
transient response.
The controller includes integrated cycle-by-cycle over-
current protection, soft-start and over-temperature dis-
able features. Independent input and enable pins pro-
vide maximum design flexibility.
The AAT2689 is available in the Pb-free 3x4mm 16-pin
TDFN package. The rated operating temperature range is
-40°C to 85°C.
Features
• 2-Output Step-Down Converters:
▪
Channel 1 (Buck): V
IN1
= 6V to 24V
• V
OUT1
adjustable from 1.5V to 5.5V
• I
OUT1
up to 2.5A
• High Switching Frequency
• Voltage Mode Control
• 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
• High Accuracy ±1.5%
• Small Solution Size
▪
System on a Chip
▪
Ultra-small External L/C
• Shutdown Current <35μA
• Independent Enable Pins
• Adjustable Over-Current Protection
• Over-Temperature Protection
• Internal Soft Start
• 3x4mm 16-Pin TDFN Low Profile Thermally Enhanced
Package
• -40°C to 85°C Temperature Range
Applications
•
•
•
•
DSL and Cable Modems
Notebook Computers
Satellite Settop Box
Wireless LAN Systems
Typical Application
C4
0.1µF
V
IN1
6.0V -24.0V
1
TDFN34-16
LX1
BST1
VL1
IN1
RS1
OS1
FB1
D2
L1 4.7µH/5.3A
C8
330pF
R5
499
V
OUT1
3.3V/2.5A
D1
C6
2.2µF
R2
2k
C7
220nF
R3
27.4k
C9,C11
2x22µF
EN1
C1
220µF
25V
+
C15
1µF
25V
V
IN2
EN1
IN2
C5
2.2µF
EN2
AAT2689
R1 24.3K
C2 470pF
C3 56pF
C10
2.2µF
V
OUT2
1.8V/600mA
R4
6.04k
COMP1
OUT2
GND
2689.2008.06.1.0
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