Datasheet
LTC3547
3
3547fa
V
IN
(V)
2.5
100
90
80
70
60
50
40
30
45
3547 G02
3 3.5
4.5 5.5
EFFICIENCY (%)
V
OUT
= 1.8V
I
OUT
= 0.1mA
I
OUT
= 1mA
I
OUT
= 10mA
I
OUT
= 100mA
I
OUT
= 300mA
TEMPERATURE (ºC)
–50
60
50
55
45
40
35
30
25
20
25 75
3547 G03
–25 0
50 100
SUPPLY CURRENT (µA)
RUN1 = RUN2 = V
IN
I
LOAD
= 0A
V
IN
= 5.5V
V
IN
= 2.7V
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
R
DS(ON)
Channel 1 (Note 4)
Top Switch On-Resistance
Bottom Switch On-Resistance
Channel 2 (Note 4)
Top Switch On-Resistance
Bottom Switch On-Resistance
V
IN
= 3.6V, I
SW
= 100mA
V
IN
= 3.6V, I
SW
= 100mA
V
IN
= 3.6V, I
SW
= 100mA
V
IN
= 3.6V, I
SW
= 100mA
0.8
0.75
0.8
0.75
1.05
1.05
1.05
1.05
Ω
Ω
Ω
Ω
I
SW(LKG)
Switch Leakage Current V
IN
= 5V, V
RUN
= 0V 0.01 1 µA
t
SOFTSTART
Soft-Start Time V
FB
From 10% to 90% Full-Scale 0.450 0.650 0.850 ms
V
RUN
RUN Threshold High
●
0.4 1 1.2 V
I
RUN
RUN Leakage Current
●
0.01 1 µA
V
BURST
Output Ripple in Burst Mode Operation V
OUT
= 1.5V, C
OUT
= 4.7µF 20 mV
P-P
The ● denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
CC
= 3.6V, unless otherwise noted.
ELECTRICAL CHARACTERISTICS
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 LTC3547E is guaranteed to meet specifi ed performance
from 0°C to 85°C. Specifi cations over the –40°C and 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 4: The DFN switch on-resistance is guaranteed by correlation to
wafer level measurements.
Note 5: Guaranteed by long term current density limitations.
Note 6: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specifi ed maximum operating junction
temperature may impair device reliability.
Burst Mode Operation Effi ciency vs Input Voltage
Supply Current vs Temperature
TYPICAL PERFOR A CE CHARACTERISTICS
UW
2.5µs/DIV
V
OUT
50mV/DIV
I
L
50mA/DIV
SW, AC
COUPLED
5V/DIV
3547 G01
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 20mA