Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
.
Page 1 of 21 V 1.0
AAT1205
Details are subject to change without notice
400-mA MULTI-INPUT LOW-DROPOUT REGULATOR WITH DUAL
OUTPUT POWER MANAGEMENT
Features
Complete Power Management
Automatic Input Voltage Selection
Input Voltage Source Detector With
Hysteresis
400-mA Load Current Capability With
VCC50VSB50 or AUX33 Input Source
Integrated Low
( )
on
DS
r
Switch
Dual Regulated Output 3.3Vfixed& 2.5V
fixed
Output Short Circuit Protection (SCP)
Pin Configuration
Description
The AAT1205 is a multi-input low-dropout
regulator (LDO) specially designed for LAN cards.
It provides advanced dual constant output supply
3.3V & 2.5V at the output capable of driving a
400-mA load. The output (OUT25) can be
disabled by connecting EN25 pin to GND.
The AAT1205 is equipped with dual regulated
power output for systems with multiple input
sources and require dual constant voltage source
with a low-dropout voltage. This is an intelligent
power source selection device with a low-dropout
regulator for either VCC50 or VSB50 inputs, and
a low-resistance bypass switch for the AUX33
input.
The AAT1205 allows transitions to progress
smoothly from one input supply to another without
generating a glitch outside of the specified range
of 3.3V & 2.5V output. Furthermore, this device
has an incorporated reverse-blocking scheme to
prevent excessive leakage from the input terminals
in the event that the output voltage is greater than
the input voltage.
The input voltage is prioritized in the following
order: VCC50, VSB50, AUX33.
VSB50
VCC50
OUT33
AUX33
GND
GND
EN25
OUT25
1
2
3
4
8
7
6
5
( 8-PIN SOP )
TOP VIEW
Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
.
Page 2 of 21 V 1.0
AAT1205
Function Table
INPUT VOLTAGE STATUS
V
INPUT SELECTED
OUTPUT
V
OUTPUT
ImA
EN25 VCC50 VSB50 AUX33 VCC50/VSB50/AUX33
OUT33
OUT25 Iout33+Iout25
Hi 0 0 0
None
0
0
0
Low
0 0 0
None
0
0
0
Hi 0 0 3.3
AUX33
3.3
2.5
400
Low 0 0 3.3
AUX33
3.3
0
400
Hi 0 5 0
VSB50
3.3
2.5
400
Low
0 5 0
VSB50
3.3
0
400
Hi 0 5 3.3
VSB50
3.3
2.5
400
Low 0 5 3.3
VSB50
3.3
0
400
Hi 5 0 0
VCC50
3.3
2.5
400
Low
5 0 0
VCC50
3.3
0
400
Hi 5 0 3.3
VCC50
3.3
2.5
400
Low 5 0 3.3
VCC50
3.3
0
400
Hi 5 5 0
VCC50
3.3
2.5
400
Low
5 5 0
VCC50
3.3
0
400
Hi 5 5 3.3
VCC50
3.3
2.5
400
Low 5 5 3.3
VCC50
3.3
0
400
Pin Description
TERMINAL
NAME NO.
I/O Description
VSB50 1
I
5V Standby Supply Input
VCC50 2
I
5V Main Supply Input
OUT33 3
O
3.3V Regulated Output
AUX33 4
I
3.3V Auxiliary Supply Input
OUT25 5
O
2.5V Regulated Output
EN25 6
I
Enable Input of OUT25
GND 7
I
Ground
GND 8
I
Ground
Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
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Page 3 of 21 V 1.0
AAT1205
Absolute Maximum Ratings
Main Supply Voltage,
(
)
50
VCC
V
..............................................................
5
.
0
-
V~7V
Standby Supply Voltage,
(
)
50
VSB
V
..........................................................
5
.
0
-
V~7V
Auxiliary Supply Voltage,
(
)
33
AUX
V
..........................................................
5
.
0
-
V~7V
Output Current Limit,
(
)
LIMIT
I
.................................................................1.5A
Continuous Power Dissipation,
d
P see Note 1........................................ 1.6W
Electrostatic Discharge Susceptibility, Human Body Mode................................2kV
Operating Ambient Temperature Range,
C
T ................................................0 to 70
Storage Temperature Range,
storage
T
..........................................................
45
-
to
+125
Operating Junction Temperature Range,
J
T ...................................................
5
-
to
+130
Lead Temperature Soldering for 10 seconds,
(
)
LEAD
T
................................260
Note 1
The device deteriorates with increase in ambient temperature,
C
T
. See Thermal Information section.
Recommended Operating Conditions
Parameter Min Typ
Max
Unit
5V Main Supply Input, VCC50
4.5
-
5.5
V
5V Standby Supply Input,
VSB50
4.5 - 5.5 V
3.3V Auxiliary Supply Input,
AUX33
3.0 - 3.6 V
Load Capacitance,
L
C
4.23 4.70 5.17
F
Load Current,
L
I
0 -
400
mA
Ambient Temperature,
C
T
0 - 70
Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
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Page 4 of 21 V 1.0
AAT1205
Electrical Characteristics Over Recommended Operating Free-Air Temperature,
T
C
= 0 to 70 ,
C
L
= 4.7F (unless otherwise specified)
Parameter Symbol
Test
Condition
Min
Typ
Max
Unit
5V Inputs
VCC50
VSB50
4.5
5.0
5.5
V
3.3V Output
OUT33
33
out
I
+
25
out
I
= 400mA
3.135 3.300
3.465
V
2.5V Output
OUT25
33
out
I
=0,
25
out
I
= 300mA
2.375 2.500
2.625
V
Line Regulation Voltage
(
)
VI
O
V
VSB50 or VCC50 = 4.5V to 5.5V
-
2
-
mV
Load Regulation Voltage
(
)
IO
O
V
20 mA
L
I 250 mA
- 40
-
mV
Quiescent Supply Current
50
I
From VCC50 VSB50 terminals,
L
I = 0
to 400mA
- 1.0
3.0
mA
AUX
I
AUX
I
From AUX33 terminal,
L
I = 0A
- 1.0
3.0
mA
Out33 Load Current
33
L
I
0.4
-
-
Out25 Load Current
25
L
I
0.3
-
-
Output Current Limit
LIMIT
I
Out33 or Out25 output shorted
to 0V
- -
1.5
A
Thermal Shutdown
(Note 2)
TSD
T
150 -
180
Thermal Hysteresis
(Note 2)
hys
T
- 15
-
Load Capacitance
L
C
Minimal ESR to insure stability of
regulated output
- 4.7
-
F
Reverse Leakage Output
Current
(
)
REV
Ikg
I
Tested for input that is grounded.
AUX33, VSB50 or VCC50 = GND,
Out33 = 3.3V
- -
50
A
Threshold Voltage, Low
LO
V
VSB50 or VCC50 4.0
4.2
4.4
V
Threshold Voltage, High
HI
V
VSB50 or VCC50 4.25
4.45
4.65
V
Auxiliary Switch
Resistance
SWITCH
R
VSB50 = VCC50 = 0V,
AUX33 = 3.3V,
L
I = 150mA
- -
0.4
JA
R
Power Pad is not soldered on the heat
spreading copper
- 80
-
Power Pad is soldered on the heat
spreading copper
- 50
-
/
W
Note 2Design targets only. Not tested in production.
Note 3Please refer to "Thermal Information"
Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
.
Page 5 of 21 V 1.0
AAT1205
Function Block
VCC50
Detector
+
-
VCC50
3.3V
AUX33
GND
Over
Temperature
Protection
OUT25
2.5V
VSB50
Detector
Control
OUT33
VSB50
3.3V
Low on Resistance
-
-
+
+
EN25
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