Datasheet

LTC3729
5
3729fb
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Input Voltage
and Mode EXTV
CC
Voltage Drop
INTV
CC
and EXTV
CC
Switch
Voltage vs Temperature
Internal 5V LDO Line Reg
Maximum Current Sense Threshold
vs Duty Factor
Maximum Current Sense Threshold
vs Percent of Nominal Output
Voltage (Foldback)
Efficiency vs Output Current
(Figure 12)
Efficiency vs Output Current
(Figure 12)
Efficiency vs Input Voltage
(Figure 12)
OUTPUT CURRENT (A)
0.1
EFFICIENCY (%)
100
80
60
40
20
0
3729 G01
1 10 100
V
OUT
= 3.3V
V
EXTVCC
= 5V
I
OUT
= 20A
f = 250kHz
V
IN
= 5V
V
IN
= 8V
V
IN
= 12V
V
IN
= 20V
OUTPUT CURRENT (A)
1
EFFICIENCY (%)
70
80
3729 G02
60
50
10 100
100
90
V
EXTVCC
= 0V
V
OUT
= 3.3V
f = 250kHz
V
EXTVCC
= 5V
V
IN
(V)
5
EFFICIENCY (%)
100
90
80
70
3729 G03
10 15 20
V
OUT
= 3.3V
V
EXTVCC
= 5V
I
OUT
= 20A
f = 250kHz
INPUT VOLTAGE (V)
0 5
0
SUPPLY CURRENT (µA)
400
1000
10
20
25
3729 G04
200
800
600
15
30
35
ON
SHUTDOWN
CURRENT (mA)
0
EXTV
CC
VOLTAGE DROP (mV)
150
200
250
40
3729 G05
100
50
0
10
20
30
50
TEMPERATURE (°C)
–50
INTV
CC
AND EXTV
CC
SWITCH VOLTAGE (V)
4.95
5.00
5.05
25 75
3729 G06
4.90
4.85
–25 0
50 100 125
4.80
4.70
4.75
INTV
CC
VOLTAGE
EXTV
CC
SWITCHOVER THRESHOLD
INPUT VOLTAGE (V)
0
4.8
4.9
5.1
15 25
3729 G07
4.7
4.6
5 10
20 30 35
4.5
4.4
5.0
INTV
CC
VOLTAGE (V)
I
LOAD
= 1mA
DUTY FACTOR (%)
0
0
V
SENSE
(mV)
25
50
75
20 40 60 80
3729 G08
100
PERCENT ON NOMINAL OUTPUT VOLTAGE (%)
0
V
SENSE
(mV)
40
50
60
100
3729 G09
30
20
0
25
50
75
10
80
70