500mA Step-Down Converter
Typical Characteristics
P-Channel R
DS(ON)
vs. Input Voltage
1000
900
750
AAT1120
N-Channel R
DS(ON)
vs. Input Voltage
120°C
100°C
700
R
DS(ON)H
(mΩ)
Ω
R
DS(ON)L
(mΩ)
Ω
800
700
600
500
400
300
2.5
3.0
3.5
4.0
85°C
650
600
550
500
450
400
350
120°C
100°C
85°C
25°C
25°C
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
4.5
5.0
5.5
6.0
300
Input Voltage (V)
Input Voltage (V)
Load Transient Response
(1mA to 500mA; V
IN
= 3.6V; V
OUT
= 1.8V;
C
OUT
= 4.7µF; C
FF
= 100pF)
2.2
2.0
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
Load Transient Response
(350mA to 500mA; V
IN
= 3.6V; V
OUT
= 1.8V;
C
OUT
= 4.7µF; C
FF
= 100pF)
Load and Inductor Current
(bottom) (400mA/div)
Load and Inductor Current
(bottom) (200mA/div)
V
O
I
O
Output Voltage
(top) (V)
1.6
1.4
1.2
1.0
0.8
0.6
V
O
I
O
Output Voltage
(top) (V)
1.8
I
LX
I
LX
Time (25µs/div)
Time (25µs/div)
Line Response
(V
OUT
= 1.8V @ 500mA)
1.90
1.85
7.0
V
O
6.5
6.0
5.5
5.0
Output Voltage
(top) (V)
1.80
1.75
1.70
1.65
1.60
1.55
1.50
Input Voltage
(bottom) (V)
V
IN
4.5
4.0
3.5
3.0
Time (25µs/div)
1120.2007.01.1.0
7
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
