Datasheet

MAX639/MAX640/MAX653
5V/3.3V/3V/Adjustable, High-Efficiency,
Low I
Q
, Step-Down DC-DC Converters
_______________________________________________________________________________________ 5
0
70
MAX639
START-UP TIME vs.
OUTPUT CURRENT
2
8
MAX639-12
OUTPUT CURRENT (mA)
START-UP TIME (ms)
20
6
12
010 40 60 80 100
V+ = 5.5V
10
4
30 50 90
V+ = 9.0V
V+ = 11.5V
MEASURED FROM THE RISING EDGE
OF V+ OR SHDN TO (V
OUT
= 5V).
0
70
MAX640/MAX653
START-UP TIME vs.
OUTPUT CURRENT
2
8
MAX639-13
OUTPUT CURRENT (mA)
START-UP TIME (ms)
20
6
0 10 40 60 80 100
10
4
30 50 90
V+ = 9.0V
V+ = 11.5V
V+ = 5.0V
MEASURED FROM THE RISING EDGE OF V+
OR SHDN TO (V
OUT
= 3.3V)(MAX640) OR
(V
OUT
= 3.0V)(MAX653). THE START-UP
TIME DIFFERENCE BETWEEN THE
MAX640 AND THE MAX653
IS NEGLIGIBLE.
L = 100
µ
H
0
30
MAX639
START-UP TIME vs.
OUTPUT CURRENT
10
30
MAX639-14
OUTPUT CURRENT (mA)
START-UP TIME (ms)
0 5 15 25
40
20
10 20
V+ = 9.0V
V+ = 11.5V
V+ = 5.5V
MEASURED FROM THE RISING EDGE
OF V+ OR SHDN TO (V
OUT
= 5.0V)
L = 470
µ
H.
0
30
MAX640/MAX653
START-UP TIME vs.
OUTPUT CURRENT
10
30
MAX639-15
OUTPUT CURRENT (mA)
START-UP TIME (ms)
05 15 25
40
20
10 20
V+ = 9.0V
V+ = 11.5V
V+ = 5.0V
MEASURED FROM THE RISING EDGE OF
V+ OR SHDN TO (V
OUT
= 3.3V)(MAX640)
OR (V
OUT
= 3.0V)(MAX653). THE
START-UP TIME DIFFERENCE BETWEEN
THE MAX640 AND THE MAX653 IS
NEGLIGIBLE.
L = 470
µ
H
_____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 3, internal feedback, L = 100µH, T
A
= +25°C, unless otherwise noted.)
0
7
NO-LOAD SUPPLY CURRENT vs.
INPUT VOLTAGE
40
60
MAX639-16
INPUT VOLTAGE (V)
NO-LOAD SUPPLY CURRENT (µA)
4
50
70
0 1 2 3 5 6 11 12
MAX639, V
OUT
= 5V
10
30
20
9810
MAX653, V
OUT
= 3V