MAX1845 Maxim, MAX1845 Datasheet - Page 7

• Manufacturer Part Number: MAX1845
• Description: Dual / High-Efficiency / Step-Down Controller with Accurate Current Limit
• Manufacturer: Maxim

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