LTC3125_15 Datasheet, PDF (3/18 Pages) Linear Technology – 1.2A Synchronous Step-Up DC/DC Converter with Input Current Limit

LTC3125
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T_A = 25°C. V_IN = 3.3V, V_OUT = 4.5V unless otherwise noted (Note 2).
PARAMETER
PROG Current Gain
Maximum Duty Cycle
Minimum Duty Cycle
Frequency
SHDN Input High
SHDN Input Low
SHDN Input Current
CONDITIONS
(Note 3)
V_FB = 1.15V
V_FB = 1.3V
V_SHDN = 1.2V
MIN TYP MAX UNITS
22.1
kΩ-A/A
l 85
92
%
l
0
%
l 1.3
1.6
1.9
MHz
1
V
0.35
V
0.3
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 LTC3125 is tested under pulsed load conditions such that
T_J ≈ T_A. The LTC3125E (E Grade) is guaranteed to meet specifications
from 0°C to 85°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
junction temperature (T_J) is calculated from the ambient temperature
(T_A) and power dissipation (P_D) according to the formula: T_J = T_A + (P_D)
(θ_JA °C/W), where θ_JA is the package thermal impedance. The maximum
ambient temperature consistent with these specifications is determined by
specific operating conditions in conjunction with board layout, the rated
package thermal resistance and other environmental factors.
Note 3: Specification is guaranteed by design and not 100% tested in
production.
Note 4: Current measurements are made when the output is not switching.
Note 5: 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 result in device degradation or failure.
Note 6: Failure to solder the exposed backside of the package to the PC
board ground plane will result in a thermal resistance much higher than
60°C/W.
TYPICAL PERFORMANCE CHARACTERISTICS (T_A = 25°C unless otherwise noted)
Efficiency vs Load Current,
V_OUT = 2.5V
100
1
90
80
0.1
70
60
50
0.01
40
30
20
10
0
0.001
0.001
V_IN = 2.1V
V_IN = 1.8V
0.0001
0.01
0.1
1
LOAD CURRENT (A)
3125 G01
Efficiency vs Load Current,
V_OUT = 3.3V
100
1
90
80
70
0.1
60
50
40
30
0.01
20
10
0
0.001
V_IN = 2.8V
V_IN = 2.4V
V_IN = 2V
0.001
0.01
0.1
1
LOAD CURRENT (A)
3125 G02
3125fa
3