Rainbow Electronics MAX653 - Manual (Page 3)

MAX639/MAX640/MAX653
5V/3.3V/3V/Adjustable, High-Efficiency,
Low I
Q
, Step-Down DC-DC Converters
_______________________________________________________________________________________ 3
__________________________________________Typical Operating Characteristics
(Circuit of Figure 3, internal feedback, L = 100µH, T A = +25°C, unless otherwise noted.)
100
50
10 µ 100 µ 1
EFFICIENCY vs.
OUTPUT CURRENT
60
MAX639-1
OUTPUT CURRENT (A)
EFFICIENCY (%)
70
80
90
1m 10m 100m
L = 100 µ H
V + = 9V
MAX639
MAX640
MAX653
100
50
10 µ 100 µ
EFFICIENCY vs.
OUTPUT CURRENT
60
MAX639-2
OUTPUT CURRENT (A)
EFFICIENCY (%)
70
80
90
1m 10m
MAX639, V+ = 6V
MAX640, V+ = 4.3V
MAX653, V+ = 4V
100m
L = 470 µ H
100
50
10 µ 100 µ
EFFICIENCY vs.
OUTPUT CURRENT
60
MAX639-3
OUTPUT CURRENT (A)
EFFICIENCY (%)
70
80
90
1m 10m
MAX639
MAX640
MAX653
100m
L = 470 µ H
V+ = 9V
Note 2: Output guaranteed by correlation to measurements of device parameters (i.e., switch on-resistance, on-times, off-times, and
output voltage trip points).
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 9V for the MAX639, V+ = 5V for the MAX640/MAX653, I LOAD = 0mA, T A = T MIN to T MAX , typical values are at T A = +25°C,
unless otherwise noted.)
PARAMETER
V
0.4 1.2
MIN TYP MAX
mA V LBO = 0.4V
UNITS
LBO Leakage Current 0.001 0.1 µA V LBO = 11.5V
LBO Delay 25 µs 50mV overdrive
2.5
SHDN Threshold 0.80 1.15 2.00 V
SHDN Pull-Up Current 0.10 0.20 0.40
Ω
µA SHDN = 0V
V
µA
T A = +25°C
T A = T MIN to T MAX
MAX639
MAX640/MAX653
2.8
LX Switch Leakage
0.003 1.0
30.0
VFB Bias Current 4.0 15.0 nA
VFB Dual-Mode Trip Point
LX Switch On-Resistance
50
0.8 1.5
VFB Threshold
1.26 1.28 1.30
mV
1.24 1.28 1.32
LBI Bias Current 2 10
LBI Threshold
1.26 1.28 1.30
nA
1.24 1.28 1.32
LBO Sink Current
0.8 2.5
CONDITIONS
V+ = 6V, T A = T MIN to T MAX , MAX639
V+ = 4V, T A = T MIN to T MAX , MAX640/MAX653
V+ = 11.5V, V LX = 0V
VFB = 2V
V+ = 9V, T A = +25°C, MAX639/MAX640/MAX653
MAX6_ _C
MAX6_ _E/M
V LBI = 2V
MAX6_ _C
MAX6_ _E/M