Max1800 digital camera step-up power supply, Typical operating characteristics (continued) – Rainbow Electronics MAX1800 User Manual
Page 6
MAX1800
Digital Camera Step-Up
Power Supply
6
_______________________________________________________________________________________
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
INPUT
= 2.4V, T
A
= +25°C, unless otherwise noted.)
0
20
60
40
80
100
0.4
0.6
0.7
0.5
0.8
0.9
1.0
1.1
1.2
AUXILIARY CONTROLLER
MAXIMUM DUTY CYCLE vs. V
DCON
_
MAX1800 toc07
V
DCON
_ (V)
MAXIMUM CYCLE (%)
0
20
10
40
30
50
60
1
100
10
1000
10,000
FB_ TO COMP_ SMALL-SIGNAL OPEN-LOOP
FREQUENCY RESPONSE
MAX1800 toc08
FREQUENCY (kHz)
SMALL-SIGNAL RESPONSE (dB)
OSCILLATOR FREQUENCY vs. R
OSC
0
1
1000
100
10
1000
400
200
800
600
MAX1800 toc10
R
OSC
(k
Ω)
OSCILLATOR FREQUENCY (kHz)
C
OSC
= 470pF
C
OSC
= 220pF
C
OSC
= 100pF
C
OSC
= 47pF
LDO STARTUP RESPONSE
MAX1800 toc12
1.00 ms/div
INPUT
CURRENT
500mA/div
LDO
OUTPUT
VOLTAGE
2V/div
V
ONA
2V/div
0V
0V
0A
MAIN LOAD = 24
Ω
LDO LOAD = 8
Ω
0
20
60
40
80
100
0
400
200
600
800
1000
MAX1800 toc09
FREQUENCY (kHz)
DEFAULT MAXIMUM DUTY CYCLE (%)
AUXILIARY CONTROLLER DEFAULT
MAXIMUM DUTY CYCLE vs. FREQUENCY
C
OSC
= 470pF
MAIN OUTPUT STARTUP RESPONSE
MAX1800 toc11
1.00 ms/div
INPUT
CURRENT
1A/div
MAIN
OUTPUT
VOLTAGE
2V/div
V
ONM
2V/div
0V
0V
0A
MAIN LOAD = 24
Ω