800mA Voltage-Scaling Step-Down Converter
Typical Characteristics
P-Channel R
DS(ON)
vs. Input Voltage
450
400
450
AAT1142
N-Channel R
DS(ON)
vs. Input Voltage
125°C
R
DS(ON)L
(mΩ)
Ω
400
R
DS(ON)H
(mΩ)
Ω
100°C
85°C
350
300
250
200
150
2.5
125°C
100°C
85°C
350
300
250
200
2.5
3
3.5
4
4.5
5
25°C
25°C
3
3.5
4
4.5
5
5.5
6
6.5
5.5
6
6.5
Input Voltage (V)
Input Voltage (V)
Load Transient Response
(10mA to 400mA; V
IN
= 3.6V; V
OUT
= 1.2V)
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-0.1
-0.2
Load Transient Response
(400mA to 800mA; V
IN
= 3.6V; V
OUT
= 1.0V)
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
Load and Inductor Current
(bottom) (200mA/div)
Load and Inductor Current
(bottom) (200mA/div)
Output Voltage
(top) (V)
Time (50µs/div)
Output Voltage
(top) (V)
Time (50µs/div)
No Load Quiescent Current vs. Input Voltage
(V
OUT
= 1.8V)
60
0.2
Line Response
(V
OUT
= 1.2V; I
OUT
= 650mA)
6.0
5.5
Supply Current (µA)
55
Output Voltage
(top) (VAC)
50
45
40
35
30
25
20
2.5
3.0
3.5
4.0
4.5
5.0
5.5
85°C
25°C
-40°C
0.1
0.0
-0.1
-0.2
-0.3
Input Voltage
(bottom) (V)
5.0
4.5
4.0
3.5
3.0
6.0
-0.4
Input Voltage (V)
Time (500µs/div)
8
1142.2006.07.1.0