1.8V to 28V Input, PWM Step-Up
Controllers in µMAX
Typical Operating Characteristics
(Circuits of Figures 2, 3, 4, and 5; T
A
= +25°C; unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 5V)
90
85
EFFICIENCY (%)
V
IN
= 2.7V
V
IN
= 2V
EFFICIENCY (%)
80
75
70
65
60
55
50
1
10
100
1000
10,000
LOAD CURRENT (mA)
BOOTSTRAPPED
FIGURE 3
R4 = 200kΩ
75
V
IN
= 3.6V
V
IN
= 3.3V
MAX668 toc01
MAX668/MAX669
MAX668 EFFICIENCY vs.
LOAD CURRENT (V
OUT
= 12V)
MAX668 toc02
MAX668 EFFICIENCY vs.
LOAD CURRENT (V
OUT
= 24V)
V
IN
= 12V
90
EFFICIENCY (%)
V
IN
= 8V
MAX668 toc03
95
95
95
90
85
85
V
IN
= 5V
80
V
IN
= 5V
NON-BOOTSTRAPPED
FIGURE 4
R4 = 200kΩ
1
10
100
1000
10,000
80
75
NON-BOOTSTRAPPED
FIGURE 4
R4 = 200kΩ
1
10
100
1000
LOAD CURRENT (mA)
10,000
70
LOAD CURRENT (mA)
70
MAX669 MINIMUM START-UP VOLTAGE
vs. LOAD CURRENT
MAX668 toc04
SUPPLY CURRENT vs.
SUPPLY VOLTAGE
MAX668 toc05
NO-LOAD SUPPLY CURRENT vs.
SUPPLY VOLTAGE
3500
3000
2500
2000
1500
1000
500
0
V
OUT
= 12V
BOOTSTRAPPED
FIGURE 2
R4 = 200kΩ
MAX668 toc06
3.0
MINIMUM START-UP VOLTAGE (V)
2.5
2.0
V
OUT
= 12V
1.5
1.0
0.5
0
0
V
OUT
= 5V
1200
1000
SUPPLY CURRENT (µA)
800
600
400
200
MAX668
0
0
5
10
15
20
25
MAX669
CURRENT INTO V
CC
PIN
R
OSC
= 500kΩ
4000
NO-LOAD SUPPLY CURRENT (µA)
BOOTSTRAPPED
FIGURE 2
100 200 300 400 500 600 700 800 900 1000
LOAD CURRENT (mA)
30
0
2
4
6
8
10
12
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SHUTDOWN CURRENT vs.
SUPPLY VOLTAGE
MAX669
MAX668 toc07
SUPPLY CURRENT vs.
TEMPERATURE
MAX668 toc08
LDO DROPOUT VOLTAGE vs.
LDO CURRENT
MAX668 toc09
3.5
3.0
SHUTDOWN CURRENT (µA)
2.5
2.0
1.5
1.0
0.5
CURRENT INTO V
CC
PIN
0
0
5
10
15
20
25
290
270
SUPPLY CURRENT (µA)
250
230
R
OSC
= 200kΩ
210
R
OSC
= 500kΩ
190
170
150
R
OSC
= 100kΩ
300
250
V
IN
= 3V
200
150
V
IN
= 4.5V
100
50
0
MAX668
30
-40
-20
0
20
40
60
80
100
LDO DROPOUT VOLTAGE (mV)
0.1
1
LDO CURRENT (mA)
10
20
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
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5
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
