Triple-Output Charge Pump Regulator
Typical Characteristics
V
IN
= 3.3V, V
OUT
= 5V, V
POS
= 12.5V, V
NEG
= -7.8V, C
IN
= C
FLY
= 1µF, C
OUT
= 4.7µF; T
A
= 25°C, unless otherwise noted.
AAT2820
Negative Charge Pump Efficiency
vs. Output Current
(No Load at V
POS
and V
OUT
)
70
65
60
Load Transient Response
(10mA - 100mA; V
IN
= 3.3V)
5.05
5.00
V
IN
= 2.7V
Output Current
(50mA/div) (bottom)
Output Voltage
(50mV/div) (top)
4.95
4.90
4.85
100mA
10mA
R
OUT
= 500Ω to 55Ω
0.15
0.10
0.05
0.00
-0.05
Efficiency (%)
55
50
45
40
35
30
25
20
0
5
10
15
20
25
30
V
IN
= 3.3V
V
IN
= 4.2V
V
IN
= 3.0V
Time (50μs/div)
μ
Output Current (mA)
Output Ripple Waveform
(V
OUT
= 5V @ 100mA; V
POS
= 12.5V @ 10mA;
V
NEG
= -7.8V @ 10mA)
V
OUT
(20mV/div)
V
POS
(10mV/div)
3V
5V Output Startup Time
with 100mA Load
Enable
(1V/div)
0V
+5V
V
NEG
(10mV/div)
Time (250ns/div)
V
OUT
(1V/div)
0V
μ
Time (100μs/div)
AAT2820 Power-Up Sequence
AAT2820-1 Power-Up Sequence
(V
IN
= 4.2V)
Enable
(2V/div)
V
OUT
(5V/div)
V
POS
(10V/div)
V
NEG
(10V/div)
μ
Time (250μs/div)
4V
0V
5V
0V
10V
0V
0V
-10V
Enable
(2V/div)
V
OUT
(5V/div)
V
POS
(10V/div)
V
NEG
(10V/div)
μ
Time (250μs/div)
4V
0V
5V
0V
10V
0V
0V
-10V
2820.2006.04.1.4
7
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
