LTC3538 Datasheet, PDF (3/16 Pages) Linear Technology – 800mA Synchronous Buck-Boost DC/DC Converter

LTC3538
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C. V_IN = V_OUT = 3.6V, unless otherwise noted.
PARAMETER
Minimum Duty Cycle
Frequency Accuracy
CONDITIONS
FB = 1.2V
MIN TYP MAX UNITS
●
0
%
● 0.8
1
1.2
MHz
Internal Soft-Start Time
1.5
ms
Error Amp A_VOL
Error Amp Source Current
Error Amp Sink Current
V_C Shutdown Threshold (Off)
V_C Output Current in Shutdown
BURST Threshold (High)
BURST Threshold (Low)
V_C = 1.5V, FB = OV
V_C = 1.5V, FB = 1.2V
IC is Disabled
V_C = GND
80
dB
–13
μA
130
μA
●
0.25
V
–1
–3
μA
● 1.4
V
●
0.4
V
BURST Input Current
V_BURST = 3.6V
0.1
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 LTC3538 is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: This IC includes over-temperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when over-temperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may result in device degradation or failure.
Note 4: The IC is tested in a feedback loop to make the measurement.
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise noted
Li-Ion to 3.3V Efficiency
100
90
80
70
60 _{Burst Mode}
50 ^OPERATION
40
30
20
10
0.1
V_IN = 2.7V
V_IN = 3.6V
V_IN = 4.2V
1
10
100
LOAD CURRENT (mA)
1000
3538 G01
Efficiency and Power Loss vs
Load Current
100
FIXED FREQUENCY
90
1000
80
Burst Mode
100
70
OPERATION
60
50
10
40
POWER LOSS
30
FIXED FREQUENCY
1
20
POWER LOSS BURST
10
0
0.1
0.1
1
10
100
1000
LOAD CURRENT (mA)
3538 G02
Switch Pins Before Entering
Boost Mode
SW1
2V/DIV
SW2
2V/DIV
50ns/DIV
V_IN = 2.9V
V_OUT = 3.3V AT 500mA
3538 G03
3538fb
3