LTC3547
ELECTRICAL CHARACTERISTICS
SYMBOL
R
DS(ON)
PARAMETER
Channel 1 (Note 4)
Top Switch On-Resistance
Bottom Switch On-Resistance
Channel 2 (Note 4)
Top Switch On-Resistance
Bottom Switch On-Resistance
Switch Leakage Current
Soft-Start Time
RUN Threshold High
RUN Leakage Current
Output Ripple in Burst Mode Operation
V
OUT
= 1.5V, C
OUT
= 4.7µF
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 3.6V, unless otherwise noted.
CONDITIONS
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
V
IN
= 5V, V
RUN
= 0V
V
FB
From 10% to 90% Full-Scale
●
●
MIN
TYP
0.8
0.75
0.8
0.75
0.01
MAX
1.05
1.05
1.05
1.05
1
0.850
1.2
1
UNITS
Ω
Ω
Ω
Ω
µA
ms
V
µA
mV
P-P
I
SW(LKG)
t
SOFTSTART
V
RUN
I
RUN
V
BURST
0.450
0.4
0.650
1
0.01
20
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 specified performance
from 0°C to 85°C. Specifications 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 specified maximum operating junction
temperature may impair device reliability.
TYPICAL PERFOR A CE CHARACTERISTICS
Burst Mode Operation
100
SW, AC
COUPLED
5V/DIV
EFFICIENCY (%)
V
OUT
50mV/DIV
90
80
70
60
50
3547 G01
SUPPLY CURRENT (µA)
I
L
50mA/DIV
2.5µs/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 20mA
U W
Efficiency vs Input Voltage
V
OUT
= 1.8V
60
55
50
45
Supply Current vs Temperature
RUN1 = RUN2 = V
IN
I
LOAD
= 0A
V
IN
= 5.5V
40
35
30
25
V
IN
= 2.7V
40
30
2.5
I
OUT
= 0.1mA
I
OUT
= 1mA
I
OUT
= 10mA
I
OUT
= 100mA
I
OUT
= 300mA
3
3.5
4.5
4
V
IN
(V)
5
5.5
3547 G02
20
–50
–25
50
25
0
TEMPERATURE (ºC)
75
100
3547 G03
3547fa
3
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
