Datasheet

Typical Operating Characteristics
(Circuit of Figure 3, 500kHz switching, V
IN
= 17V, V
OUT
= 3.3V, T
A
= +25°C, unless otherwise noted.)
MAX8650
4.5V to 28V Input Current-Mode Step-Down
Controller with Adjustable Frequency
6 _______________________________________________________________________________________
EFFICIENCY vs. LOAD CURRENT
LOAD CURRENT (A)
EFFICIENCY (%)
MAX8650 toc01
0
10
20
30
40
50
60
70
80
90
100
1 10 100
12V INPUT, 3.3V OUTPUT
12V INPUT, 2.5V OUTPUT
12V INPUT, 1.8V OUTPUT
24V INPUT, 3.3V OUTPUT
EFFICIENCY vs. LOAD CURRENT
(CIRCUIT OF FIGURE 4)
LOAD CURRENT (A)
EFFICIENCY (%)
MAX8650 toc02
0
10
20
30
40
50
60
70
80
90
110
12V INPUT, 1.25V OUTPUT
12V INPUT, 0.9V OUTPUT
LOAD REGULATION
LOAD CURRENT (A)
OUTPUT VOLTAGE (V)
MAX8650 toc03
0 5 10 15
3.270
3.275
3.280
3.285
3.290
3.295
3.300
3.305
3.310
LINE REGULATION
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
MAX8650 toc04
6 101418222630
3.270
3.275
3.280
3.285
3.290
3.295
3.300
3.305
3.310
NO LOAD
15A LOAD
R
ILIM1
vs. PEAK CURRENT LIMIT
PEAK CURRENT LIMIT V
CS+
- V
CS-
(V)
R
ILIM1
(kΩ)
MAX8650 toc05
0.03 0.04 0.05 0.06 0.07 0.08
20
25
30
35
40
45
50
55
60
OSCILLATOR FREQUENCY
vs. INPUT VOLTAGE
INPUT VOLTAGE (V)
OSCILLATOR FREQUENCY (kHz)
MAX8650 toc06
6 101418222630
470
480
490
500
510
520
530
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
I
OUT
V
OUT
5A/div
0V
100mV/div
(AC-COUPLED)
40μs/div
STEP-LOAD RESPONSE
7.5A TO 15A TO 7.5A
MAX8650 toc07
I
OUT
V
OUT
5A/div
0V
50mV/div
(AC-COUPLED)
100μs/div
STEP-LOAD RESPONSE
-8A TO 8A TO -8A (CIRCUIT OF FIGURE 4)
MAX8650 toc08