Datasheet
LT3971/LT3971-3.3/LT3971-5
4
3971fd
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency, V
OUT
= 3.3V No Load Supply Current No Load Supply Current
Efficiency, V
OUT
= 5V Efficiency, V
OUT
= 3.3V Efficiency, V
OUT
= 5V
T
A
= 25°C, unless otherwise noted.
LOAD CURRENT (A)
EFFICIENCY (%)
3971 G01
100
30
40
50
60
70
80
90
20
0 1.210.80.60.40.2
V
IN
= 12V
V
IN
= 24V
V
IN
= 36V
V
OUT
= 5V
R1 = 1M
R2 = 309k
LOAD CURRENT (A)
EFFICIENCY (%)
3971 G02
100
30
40
50
60
70
80
90
20
0 1.210.80.60.40.2
V
IN
= 12V
V
IN
= 24V
V
IN
= 36V
LOAD CURRENT (mA)
EFFICIENCY (%)
3971 G03
100
30
20
10
40
50
60
70
80
90
0
0.01 10001001010.1
V
IN
= 36V
V
OUT
= 5V
R1 = 1M
R2 = 309k
V
IN
= 24V
V
IN
= 12V
LOAD CURRENT (mA)
EFFICIENCY (%)
3971 G04
90
30
20
10
40
50
60
70
80
0
0.01 10001001010.1
V
IN
= 12V
V
IN
= 24V
V
IN
= 36V
TEMPERATURE (°C)
INPUT CURRENT (µA)
3971 G05
100
10
1
–55 –25 1551259565355
DIODES, INC.
DFLS2100
5 10 20 3015 25 35
INPUT VOLTAGE (V)
INPUT CURRENT (µA)
1.0
3971 G06
2.0
1.5
4.0
3.5
3.0
2.5
LT3971-5
LT3971
V
OUT
= 3.3V
LT3971-3.3
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LT3971E is guaranteed to meet performance specifications
from 0°C to 125°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization, and correlation with statistical process controls. The
LT3971I is guaranteed over the full –40°C to 125°C operating junction
temperature range. High junction temperatures degrade operating
lifetimes. Operating lifetime is derated at junction temperatures greater
than 125°C.
Note 3: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the switch.
Note 4: This is the minimum input voltage for operation with accurate FB
regulation. Minimum input voltage for output regulation depends on the
application circuit.
PG Leakage V
PG
= 3V 0.02 1 µA
PG Sink Current V
PG
= 0.4V
l
300 570 μA
SYNC Threshold 0.6 0.8 1.0 V
SYNC Pin Current 0.1 nA
SS Source Current V
SS
= 1V 0.6 1 1.6 μA
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
EN
= 12V, V
BD
= 3.3V unless otherwise noted. (Note 2)