PRODUCT DATASHEET
AAT2687
SystemPower
TM
PMIC Solution for 24V Systems with 2 High Performance Step-Down Converters
Features
• 2-Output Step-Down Converters:
▪
Channel 1 Step-Down: V
IN1
= 6V to 24V
• V
OUT1
Adjustable from 1.5V to 5.5V
• I
OUT1
up to 4.5A
• 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
• Programmable Over-Current Protection
• Over-Temperature Protection
• Internal Soft Start
• 4x5mm 24-Pin TQFN Low Profile Thermally Enhanced
Package
• -40°C to 85°C Temperature Range
General Description
The AAT2687 provides two independently regulated DC
outputs; consisting of a high voltage step-down regula-
tor and a low input voltage 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 6.0 to 24V, providing up to 4.5A output current.
490kHz fixed switching frequency allows small L/C filter-
ing 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 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 AAT2687 is available in the Pb-free, 4x5mm 24-pin
TQFN package. The rated operating temperature range is
-40°C to 85°C.
Applications
•
•
•
•
DSL and Cable Modems
Notebook Computers
Satellite Settop Box
Wireless LAN Systems
Typical Application
C3
0.1µF
2
1
D1
BAS16
C14
2.2µF
LX1
BST
VL1
RS1
OS1
IN1
FB1
R1
3.92K
C5
2.2nF
D2
R2 C4
2k 220nF
L1
4.7µH 5.3A
C10
2.2nF
R5
450
R3
8.87k
C8
C9
C7
22µF 22µF 22µF
V
OUT1
3.3V/4.5A
J1
V
IN1
6.0V - 24.0V
COMP1
AAT2687
EN1
V
IN2
+
C1
220µF
25V
C13
1µF
25V
C2
2.2µF
IN2
OUT2
C12
2.2µF
EN2 GND
TQFN45-24
C6
R4
V
OUT2
150pF
1.96k
1.8V/600mA
2687.2008.06.1.0
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