LTC3547B_15 Datasheet, PDF (3/16 Pages) Linear Technology – Dual Monolithic 300mA Synchronous Step-Down Regulator

LTC3547B
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
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
ΔV_LINEREG
ΔV_LOADREG
I_S
f_OSC
Reference Voltage Line Regulation
Output Voltage Load Regulation
Input DC Supply Current
Active Mode (Note 4)
Shutdown
Oscillator Frequency
V_IN = 2.5V to 5.5V
I_LOAD = 50mA to 300mA
V_FB1 = V_FB2 = 0.95 × V_FBREG
RUN1 = RUN2 = 0V, V_IN = 5.5V
V_FB = 0.6V
0.3
0.5
%/V
0.5
%
450
700
μA
0.1
1
μA
● 1.8
2.25
2.7
MHz
I_LIM
Peak Switch Current Limit
V_IN = 2.5V, V_FB < V_FBREG, Duty Cycle < 35%
Channel 1 (300mA)
400
550
mA
Channel 2 (300mA)
400
550
mA
R_DS(ON)
I_SW(LKG)
Channel 1 (Note 3)
Top Switch On-Resistance
Bottom Switch On-Resistance
Channel 2 (Note 3)
Top Switch On-Resistance
Bottom Switch On-Resistance
Switch Leakage Current
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
0.8
1.05
Ω
0.75 1.05
Ω
0.8
1.05
Ω
0.75 1.05
Ω
0.01
1
μA
t_SOFTSTART
V_RUN
Soft-Start Time
RUN Threshold High
V_FB From 10% to 90% Full-Scale
0.450 0.650 0.850
ms
● 0.4
1
1.2
V
I_RUN
RUN Leakage Current
●
0.01
1
μA
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 LTC3547BE 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. The LTC3547BI is guaranteed over the
–40°C to 125°C operating temperature range.
Note 4: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
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.
Note 3: The DFN switch on-resistance is guaranteed by correlation to
wafer level measurements.
TYPICAL PERFOR A CE CHARACTERISTICS T_A = 25°C unless otherwise specified.
Pulse Skip 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 = 1mA
10μs/DIV
3547b G01
Efficiency vs Input Voltage
100
V_OUT = 1.8V
90
80
70
60
50
I_OUT = 0.1mA
I_OUT = 1mA
40
I_OUT = 10mA
30
I_OUT = 100mA
I_OUT = 300mA
20
10
2.5 3
3.5 4 4.5 5 5.5
V_IN (V)
3547b G02
Supply Current vs Temperature
400
I_LOAD = 0A
350
V_IN = 5.5V
300
250
V_IN = 2.7V
200
150
100
–50 –25
0 25 50
TEMPERATURE (ºC)
75 100
3547b G03
3547bfb
3