800mA Voltage-Scaling Step-Down Converter
Typical Characteristics
Efficiency vs. Load
(V
OUT
= 1.8V)
100
90
2.0
AAT1142
DC Regulation
(V
OUT
= 1.8V)
1.6
1.2
0.8
0.4
0.0
-0.4
-0.8
-1.2
-1.6
-2.0
0
1
10
100
1000
Output Accuracy (%)
V
IN
= 3.6V V
IN
= 2.7V
Efficiency (%)
80
70
60
50
40
30
0
1
10
100
1000
V
IN
= 5.0V
V
IN
= 4.2V
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
V
IN
= 5.0V
PWM Only
Mode
Output Current (mA)
Output Current (mA)
Soft Start
(V
IN
= 3.6V; V
OUT
= 1.8V; I
OUT
= 800mA)
Line Regulation
(V
OUT
= 1.0V)
3.5
3
Output and Enable Voltage
(top) (V)
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
1.00
Output Accuracy (%)
0.75
0.50
0.25
0.00
-0.25
-0.50
-0.75
-1.00
2.5
3.0
3.5
2.5
2
1.5
1
0.5
0
-0.5
I
OUT
= 650mA
Inductor Current
(bottom) (A)
I
OUT
= 100mA
4.0
4.5
I
OUT
= 0mA
5.0
5.5
Time (50µs/div)
Input Voltage (V)
Output Voltage Accuracy vs. Temperature
(V
IN
= 3.6V; V
OUT
= 1.0V; I
OUT
= 400mA)
2.0
1.5
4.0
2.0
Switching Frequency vs. Temperature
(V
IN
= 3.6V; V
OUT
= 1.0V; I
OUT
= 400mA)
Accuracy (%)
Variation (%)
-30
-20
-10
0
10
20
30
40
50
60
70
80
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
-40
0.0
-2.0
-4.0
-6.0
-8.0
-10.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
°
Temperature (°C)
°
Temperature (°C)
1142.2006.07.1.0
7
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
