Datasheet

LT3745
8
3745f
Typical perForMance characTerisTics
I
VCC
vs V
CC
– Shutdown Mode
I
VCC
vs V
CC
– Channel Off, Data Off
V
CC
UVLO Threshold
vs Temperature
EN/UVLO UVLO Threshold
vs Temperature
(V
IN
- V
CAP
) UVLO Threshold
vs Temperature Oscillator Frequency f
OSC
vs R
T
Buck Efficiency
Shutdown I
VIN
vs V
IN
Quiescent I
VIN
vs V
IN
0
60
65
EFFICIENCY (%)
70
80
75
90
85
100
95
0.1 0.2 0.3
LOAD CURRENT (A)
0.4
3745 G10
0.5 0.6 0.7 0.8 0.9 1.0
48V
IN
, 4V
OUT
at 200kHz
24V
IN
, 12V
OUT
at 1MHz
12V
IN
, 4V
OUT
at 500kHz
0
0
I
VIN
(µA)
1
3
2
4
5
10 20
V
IN
(V)
3745 G11
30 40 50 60
T = 25°C
T = 125°C
T = –40°C
0
0.38
I
VIN
(mA)
0.39
0.41
0.40
0.42
0.43
10 20
V
IN
(V)
3745 G12
30 40 50 60
T = 25°C
T = 125°C
T = –40°C
3.0
0
I
VCC
(µA)
2
6
4
8
3.5 4.0
V
CC
(V)
3745 G13
4.5 5.0 5.5
T = 25°C
T = 125°C
T = –40°C
–50
4.40
V
IN
- V
CAP
(V)
4.60
4.50
4.70
4.80
4.90
–25 25 50 75 100 1250
JUNCTION TEMPERATURE (°C)
3745 G17
UVLO
–
UVLO
+
20 60 100 180 220 260
0
f
OSC
(kHz)
400
200
600
800
1000
140 300
R
T
(kΩ)
3745 G18
T
A
= 25°C, unless otherwise noted.
3.0
3.05
I
VCC
(mA)
3.25
3.20
3.15
3.10
3.35
3.30
3.00
3.5 4.0
V
CC
(V)
3745 G14
4.5 5.0 5.5
T = 25°C
T = 125°C
T = –40°C
–50
2.60
V
CC
(V)
2.75
2.70
2.65
2.80
2.85
2.90
–25 25 50 75 100 1250
JUNCTION TEMPERATURE (°C)
3745 G15
UVLO
–
UVLO
+
–50
1.20
V
EN/UVLO
(V)
1.26
1.24
1.22
1.28
1.30
1.32
–25 25 50 75 100 1250
JUNCTION TEMPERATURE (°C)
3745 G16
UVLO
–
UVLO
+