Typical operating characteristics (continued) – Rainbow Electronics MAX1845 User Manual
Page 7
MAX1845
Dual, High-Efficiency, Step-Down
Controller with Accurate Current Limit
_______________________________________________________________________________________
7
0
4.5
3.0
1.5
6.0
7.5
9.0
10.5
12.0
13.5
15.0
5
15
10
20
25
30
MAX1845 toc03A
SUPPLY VOLTAGE V+ (V)
SUPPLY CURRENT (mA)
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE (SKIP = V
CC
)
I
CC
V
CC
= V
DD
= 5V
I
DD
I+ (25
µA TYP)
0
100
200
300
400
500
600
700
800
900
1000
1100
MAX1845 toc03B
SUPPLY VOLTAGE V+ (V)
SUPPLY CURRENT (
µ
A)
5
10
15
20
25
30
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE (SKIP = GND)
V
CC
= V
DD
= 5V
I
DD
(600nA typ)
I
CC
I+
10
0.01
10
1
0.1
60
70
80
90
100
40
50
20
30
MAX1845 toc04a
LOAD CURRENT (A)
EFFICIENCY (%)
EFFICIENCY vs. LOAD CURRENT
(8A COMPONENTS, SKIP = V
CC
)
V+ = 7V
V+ = 20V
V+ = 12V
OUT1 = 1.8V
50
0.01
10
1
0.1
75
80
85
90
95
100
65
70
55
60
MAX1845 toc04b
LOAD CURRENT (A)
EFFICIENCY (%)
EFFICIENCY vs. LOAD CURRENT
(8A COMPONENTS, SKIP = GND)
V+ = 7V
V+ = 20V
OUT1 = 1.8V
V+ = 12V
10
50
30
70
90
110
130
150
170
190
210
230
250
0
0.5
1.0
1.5
2.0
2.5
CURRENT-LIMIT TRIP POINT
vs. ILIM VOLTAGE
MAX1845 toc05
ILIM VOLTAGE (V)
CURRENT-LIMIT TRIP POINT (mV)
10
0.01
10
1
0.1
60
70
80
90
100
40
50
20
30
MAX1845 toc04c
LOAD CURRENT (A)
EFFICIENCY (%)
EFFICIENCY vs. LOAD CURRENT
(4A COMPONENTS, SKIP = V
CC
)
V+ = 7V
V+ = 20V
V+ = 12V
OUT2 = 2.5V
80
75
0.01
10
1
0.1
95
100
90
85
MAX1845 toc04d
LOAD CURRENT (A)
EFFICIENCY (%)
EFFICIENCY vs. LOAD CURRENT
(4A COMPONENTS, SKIP = GND)
V+ = 7V
V+ = 12V
V+ = 20V
OUT2 = 2.5V
1.0
1.2
1.1
1.4
1.3
1.6
1.5
1.7
1.9
1.8
2.0
1.0
1.2
1.3
1.1
1.4
1.5
1.6
1.7
1.8
MAX1845 toc06
OVP VOLTAGE (V)
NORMALIZED THRESHOLD (V)
NORMALIZED OVERVOLTAGE PROTECTION
THRESHOLD vs. OVP VOLTAGE
MAX1845 toc07a
I
OUT2
2A/div
20µs/div
V
OUT2
100mV/div
LOAD-TRANSIENT RESPONSE
(4A COMPONENTS, PWM MODE, V
OUT2
= 2.5V)
Typical Operating Characteristics (continued)
(Circuit of Figure 1, components from Table 1, V
IN
= 15V, SKIP = GND, TON = unconnected, T
A
= +25°C, unless otherwise noted.)