LTC3521 Datasheet, PDF (3/20 Pages) Linear Technology – Wide VIN, 1A Buck-Boost DC/DC and Dual 600mA Buck DC/DC Converters

LTC3521
Electrical Characteristics The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T_J = 25°C. V_IN = 3.6V, V_OUT1 = 3.3V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Oscillator Frequency
l 0.85
1.1
1.35
MHz
SHDN1, SHDN2, SHDN3, PWM Input High Voltage
l 1.4
V
SHDN1, SHDN2, SHDN3, PWM Input Low Voltage
l
0.4
V
Power Good Outputs Low Voltage
Power Good Outputs Leakage Current
Buck Converters
I_PGOOD1 = I_PGOOD2 = I_PGOOD3 = 1mA
V_PGOOD1 = V_PGOOD2 = V_PGOOD3 = 5.5V
0.1
0.2
V
0.1
10
µA
PMOS Switch Resistance
0.205
Ω
NMOS Switch Resistance
0.170
Ω
NMOS Switch Leakage Current
PMOS Switch Leakage Current
Feedback Voltage
V_SW2 = V_SW3 = 5.5V, V_IN = 5.5V
V_SW2 = V_SW3 = 0V, V_IN = 5.5V
(Note 4)
0.1
5
µA
0.1
10
µA
l 0.585 0.6 0.612
V
Feedback Input Current
PMOS Current Limit
V_FB2 = V_FB3 = 0.6V
(Note 3)
1
50
nA
l 750 1050
mA
Maximum Duty Cycle
Minimum Duty Cycle
PGOOD Threshold
Power Good Hysteresis
Buck-Boost Converter
V_FB2 = V_FB3 = 0.55V
V_FB2 = V_FB3 = 0.66V
V_FB2,3 Falling
V_FB2,3 Returning Good
l 100
%
l
0
%
–12
–9
–6
%
2
%
Output Voltage
l 1.8
5.25
V
PMOS Switch Resistance
0.110
Ω
NMOS Switch Resistance
0.085
Ω
NMOS Switch Leakage Current
PMOS Switch Leakage Current
Feedback Voltage
V_SW1A = V_SW1B = 5.5V, V_IN = 5.5V
V_SW1A = V_SW1B = 0V, V_IN = 5.5V
(Note 4)
0.1
5
µA
0.1
10
µA
l 0.585 0.6 0.612
V
Feedback Input Current
Average Current Limit
V_FB1 = 0.6V
(Note 3)
1
50
nA
l 1.65
2.1
A
Reverse Current Limit
(Note 3)
375
mA
Maximum Duty Cycle
Minimum Duty Cycle
PGOOD Threshold
Power Good Hysteresis
V_FB1 = 0.55V
V_FB1 = 0.66V
V_FB1 Falling
V_FB1 Returning Good
l 85
94
%
l
0
%
–12
–9
–6
%
3
%
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 LTC3521 is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 3: Current measurements are performed when the LTC3521 is not
switching. The current limit values in operation will be somewhat higher
due to the propagation delay of the comparators.
Note 4: The LTC3521 is tested in a proprietary test mode that connects
each FB pin to the output of the respective error amplifier.
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 impair device reliability.
3521f