LTC3547 Datasheet, PDF (3/16 Pages) Linear Technology – Dual Monolithic 300mA Synchronous Step-Down Regulator

LTC3547
ELECTRICAL CHARACTERISTICS 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.
SYMBOL
R_DS(ON)
I_SW(LKG)
t_SOFTSTART
V_RUN
I_RUN
V_BURST
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
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
V_OUT = 1.5V, C_OUT = 4.7µF
MIN TYP MAX UNITS
0.450
● 0.4
●
0.8
0.75
0.8
0.75
0.01
0.650
1
0.01
20
1.05
1.05
1.05
1.05
1
0.850
1.2
1
Ω
Ω
Ω
Ω
µA
ms
V
µA
mV_P-P
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
SW, AC
COUPLED
5V/DIV
V_OUT
50mV/DIV
I_L
50mA/DIV
V_IN = 3.6V
V_OUT = 1.8V
I_LOAD = 20mA
2.5µs/DIV
3547 G01
Efficiency vs Input Voltage
100
V_OUT = 1.8V
90
80
70
60
50
40
30
2.5
I_OUT = 0.1mA
I_OUT = 1mA
I_OUT = 10mA
I_OUT = 100mA
I_OUT = 300mA
3 3.5 4 4.5
V_IN (V)
5 5.5
3547 G02
Supply Current vs Temperature
60
RUN1 = RUN2 = V_IN
55 ^{ILOAD = 0A}
50
45
V_IN = 5.5V
40
35
30
V_IN = 2.7V
25
20
–50 –25
0 25 50
TEMPERATURE (ºC)
75 100
3547 G03
3547fa
3