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Электронный компонент: AAT1110-S-T

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Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
.
Page 1 of 17 V 1.0
AAT1110
Details are subject to change without notice
ONE-CHANNEL STEP-DOWN PWM CONTROLLER
Features
Under-Voltage Lockout (UVLO) Protection
Totem Pole Output
Output Short Circuit Protection
Incorporates Soft-Start Function
Wide Operating Frequency
10 kHz to 1MHz
Shutdown Control
Low Dissipation Current :
Typical 1.6mA in Operation
SOP-8 & TSSOP-8 Package Available
Pin Configuration
DD
V
General Description
The AAT1110 is a one-channel step-down PWM
controller incorporating a soft-start function and a
short circuit protection (SCP) function.
Each device consists of an on-chip voltage reference,
error amplifier, pulse width modulation controller,
under-voltage protection, soft-start, and short circuit
protection circuits. Switching frequencies up to
1MHz are set by an external resistor and capacitor.
Soft-start time can be implemented by the SCP
capacitor.
Additionally, a chip enabled feature is provided to
power down and reduce the supply current to 10
A
.
With an optimized number of external components,
the AAT1110 offers a simple and cost effective
solution.
Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
.
Page 2 of 17 V 1.0
AAT1110
Pin Description
Pin No Name I/O
Description
1 CE
I
Chip Enable Input PinInternal Pull "H"
2
SCP
- Soft-Start and SCP Capacitor Connection Pin
3
DD
V
- Power
Supply
4
OUT
O Totem-Type Output Pin
5 GND
-
Ground
6
OSC
O Capacitor and Resistor Connection Pin for Setting the Oscillation Frequency
7
OE
O Error Amplifier Output Pin
8
IE
I Error Amplifier Inverting Input Pin
Absolute Maximum Ratings
Characteristics Symbol
Value
Unit
Supply Voltage
DD
V
7 V
Output Current
O
I
120
-
/+120
mA
Operating Free-Air Temperature Range
C
T
20
-
to +85
o
C
Storage Temperature Range
storage
T
45
-
to +125
o
C
Power Dissipation
d
P
500 mW
Recommended Operating Conditions
Characteristics Symbol Min Max Unit
Supply Voltage,
DD
V
DD
V
2.6 6.5 V
Error Amplifier Input Voltage
I
V
0.5 1.6 V
OSC Capacitor
OSC
C
100 10,000 pF
OSC Resistor
OSC
R
1.0 10.0
k
Oscillator Frequency
OSC
f
10 1,000 kHz
Output Current
O
I
-
+30/
30
-
mA
Operating Free-Air Temperature
C
T
20
-
+85
o
C
Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
.
Page 3 of 17 V 1.0
AAT1110
Electrical Characteristics,
DD
V
= 3.3V (Unless Otherwise Specified) (See Note 1)
Oscillator
Parameter
Test Condition
Min
Typ Max Unit
Oscillation Frequency
OSC
f
OSC
C
= 270pF,
OSC
R
= 4.2
k
400
500 600 kHz
Frequency Variation With
Temperature
T
f
5 %
Frequency Input Stability
V
f
DD
V
= 2.6V to 6.5V
1 %
Under-Voltage Protection
Parameter
Test
Condition
Min Typ
Max
Unit
Upper Threshold Voltage
UPH
V
C
T = 25
o
C
2.12 2.47 2.85 V
Lower Threshold Voltage
UPL
V
C
T = 25
o
C
1.96 2.28 2.63 V
Hysteresis (
UPH
V
UPL
V
)
HYS
V
C
T = 25
o
C
0.19 V
Note1: Typical values of all parameters are specified at
C
T
=25
o
C
Short Circuit Protection Control
Parameter
Test
Condition
Min
Typ
Max
Unit
Input Threshold Voltage
1
r
V
1.160 1.262 1.360
V
Short-Circuit Detect
Threshold Voltage
tscd
V
1.160 1.262 1.360
V
Charging Current
SCP
I
SCP
V
=0V
15
.
2
-
50
.
1
-
00
.
1
-
A

Soft-Start
Parameter
Test
Condition
Min
Typ
Max
Unit
Charging Current
CS
I
SCP
V
=0V
15
.
2
-
50
.
1
-
00
.
1
-
A
Voltage at Soft-Start
Completion
ts
V
1.160 1.262 1.360
V
Shutdown Control
Parameter
Test
Condition
Min
Typ
Max
Unit
Shutdown Enable Voltage
SE
V
0.5
V
Shutdown Release Voltage
SR
V
2.0 V
Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
.
Page 4 of 17 V 1.0
AAT1110
Electrical Characteristics,
DD
V
= 3.3V (Unless Otherwise Specified) (See Note 1)
EA (Error Amplifier)
Parameter
Test Condition
Min Typ Max
Unit
Input Threshold Voltage
T
V
OE
V = 0.7V
1.249 1.262 1.275 V
T
V
Input Stability
V
T
V
DD
V = 2.6 to 6.5V
- 2 8
mV
T
V
Variation with
Temperature
T
T
V
C
T =
20
-
o
C to 90
o
C
- 1 -
%
Input Bias Current
B
I
-
0.1
1.0
A
+
OS
V
1.4
1.7
-
Output Voltage Swing
-
OS
V
-
0.05
0.20
V
Output Sink Current
+
OS
I
OE
V =0.7V
3 20 -
mA
Output Source Current
-
OS
I
OE
V =0.7V
45
-
75
-
-
A
Open-Loop Voltage Gain
VO
A
70
85
-
dB

Output Section
Parameter
Test Condition
Min Typ Max
Unit
High-Level Output Voltage
OH
V
I
O
=
30
-
mA
1.9 2.3 - V
Low-Level Output Voltage
OL
V
I
O
=+30mA
- 0.8
1.2
V
Rise Time
RISE
t
C
L
=1,000pF
- 100 - ns
Fall Time
FALL
t
C
L
=1,000pF
- 100 - ns

Operating Current
Parameter
Test Condition
Min Typ Max
Unit
OFF
DD
I
-
Output "OFF" State
- 1.3 -
mA
Supply Current
ON
DD
I
-
R
T
=4.2
k
- 1.6 -
mA






Advanced Analog Technology, Inc.
Advanced Analog Technology, Inc
.
Page 5 of 17 V 1.0
AAT1110
How to Set the Time Constant for Soft-Start and Short Circuit Protection
1. Soft-Start
At power on, the AAT1110 operates in soft-start mode. The capacitor
SCP
C
connected to SCP pin starts
charging at a constant current. In the soft-start mode, the voltage at SCP pin (
SCP
V
) is input to the PWM
comparator, so that the ON duty of the OUT pin is controlled by the
SCP
V
. At completion of the soft-start
operation, the voltage at the SCP pin stays low; the input from soft-start circuit to the PWM comparator
stays high, and enters the short circuit protection waiting state.
Soft-Start Time
)
F
(
C
84
.
0
~
(sec)
t
SCP
s

2. Short Circuit Protection
If the switching regulator output suddenly drops due to loading effect, the error amplifier output will be
fixed at
+
OM
V
and capacitor
SCP
C
will
start charging. When the voltage at the SCP pin reaches
approximately 1.26V, the output pin will set low and SCP pin will remain low.
Once the protection circuit starts operating, the circuit can be recovered by setting the power supply.

Short Circuit Detection Time
)
F
(
C
84
.
0
~
(sec)
t
SCP
scp