5 V/3 .3 V o r Ad ju s t a b le , Hig h -Effic ie n c y,
Lo w -Dro p o u t , S t e p -Do w n DC-DC Co n t ro lle rs
49/MAX651
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, T = T
to T , unless otherwise noted. Typical values are at T = +25°C.)
MAX A
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Current-Limit Trip Level
(V+ to CS)
V
3V ≤ V+ ≤ 16V
3V ≤ V+ ≤ 16V
80
110
140
mV
CS
CS Input Current
±1
40
µA
µs
µs
ns
ns
Switch Maximum On-Time
Switch Minimum Off-Time
EXT Rise Time
t
(max) V+ = 12V
(min) V+ = 12V
24
32
1.1
25
25
ON
t
0.8
1.8
OFF
C
C
= 0.001µF, V+ = 12V
EXT
EXT
EXT Fall Time
= 0.001µF, V+ = 12V
t
ON
+ t
OFF
x 100%
Maximum Duty Cycle
95
96.5
%
t
ON
__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(T = +25°C, unless otherwise noted.)
A
SHUTDOWN CURRENT
vs. TEMPERATURE
EXT RISE AND FALL TIMES
vs. TEMPERATURE (1nF)
SUPPLY CURRENT vs. TEMPERATURE
80
4.0
60
55
C
EXT
= 1nF
3.5
3.0
2.5
2.0
1.5
1.0
0.5
78
76
74
72
70
68
V+ = 16V
V+ = 10V
50
45
V+ = 5V, t
RISE
V+ = 16V
V+ = 8V
40
35
V+ = 5V, t
FALL
30
25
V+ = 15V, t
RISE
V+ = 4V
20
15
V+ = 15V, t
FALL
V+ = 4V
-60 -40 -20 0 20 40 60 80 100 120 140
66
0
-60 -40 -20
0
20 40 60 80 100 120 140
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
EXT RISE AND FALL TIMES
vs. TEMPERATURE (5nF)
EFFICIENCY
vs. LOAD CURRENT (V = 5V)
OUT
EFFICIENCY
vs. LOAD CURRENT (V = 3.3V)
OUT
240
220
200
180
160
140
120
100
80
100
90
100
90
V
= 5V
OUT
V
= 3.3V
C
= 5nF
OUT
EXT
CIRCUIT OF
FIGURE 1
CIRCUIT OF
FIGURE 1
V+ = 5V, t
RISE
80
80
V+ = 5V, t
FALL
TOP TO
70
60
TOP TO
70
60
BOTTOM:
BOTTOM:
V
V
IN
= 4.3V
= 5V
IN
V+ = 15V, t
RISE
V
IN
= 6V
V
IN
= 8V
V
IN
= 8V
V
= 10V
= 12V
= 15V
IN
V
= 10V
= 12V
= 15V
IN
V
50
40
IN
50
40
V
IN
V
IN
60
V
IN
V+ = 15V, t
FALL
40
0.1
1
10
100
1k
10k
-60 -40 -20
0
20 40 60 80 100 120 140
0.1
1
10
100
1k
10k
LOAD CURRENT (mA)
LOAD CURRENT (mA)
TEMPERATURE (°C)
_______________________________________________________________________________________
3
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
