Datasheet

LTC3523/LTC3523-2
3
3523fb
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 LTC3523/LTC3523-2 are guaranteed to meet performance
specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process control.
Note 3: The LTC3523/LTC3523-2 include an overtemperature
shutdown that is intended to protect the device during momentary
overload conditions. Junction temperature will exceed 125°C when the
overtemperature shutdown is active. Continuous operation above the
specifi ed maximum operating junction temperature may impair device
reliability.
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN1
= V
IN2
= V
BAT
= 2.4V, V
OUT
= 3.3V, unless otherwise specifi ed.
PARAMETER CONDITIONS MIN TYP MAX UNITS
MODE Leakage Current V
MODE
= 5.5V 0.01 1 μA
Soft-Start Time 500 μs
Step-Up Converter
Input Voltage Range
l
1.8 5.25 V
Output Voltage Adjust Range (Note 6)
l
1.8 5.25 V
Feedback Voltage FB1
l
1.16 1.20 1.23 V
Feedback Input Current FB1 V
FB1
= 1.25V 0 50 nA
N-Channel Switch Leakage V
SW
= 5.5V 0.20 2 μA
P-Channel Switch Leakage V
SW
= 5.5V, V
OUT
= 0V 0.20 2 μA
N-Channel Switch On Resistance V
OUT
= 3.3V
V
OUT
= 5V
0.36
0.22
Ω
Ω
P-Channel Switch On Resistance V
OUT
= 3.3V, I
SW
= 100mA
V
OUT
= 5V, I
SW
= 100mA
0.33
0.31
Ω
Ω
Peak Inductor Current (Note 7)
l
600 1000 mA
Current Limit Delay to Output (Note 6) 40 ns
Maximum Duty Cycle V
FB
= 1V
l
80 87 %
Minimum Duty Cycle V
FB
= 1.5V
l
0%
Step-Down Converter
Input Voltage Range
l
1.8 5.5 V
Output Voltage Range (Note 6)
l
0.615 5.5 V
Feedback Voltage FB2
l
585 600 615 mV
Feedback Input Current FB2 V
FB2
= 0.625V 0 50 nA
Reference Voltage Line Regulation I
OUT
= 100mA (Notes 5, 6) 0.04 %/V
Output Voltage Line Regulation I
OUT
= 100mA, 1.6V < V
IN
< 5.5V (Note 6) 0.04 %/V
Output Voltage Load Regulation I
OUT
= 0mA to 600mA (Note 6) 1.0 %
Maximum Duty Cycle 100 %
Peak Inductor Current (Note 7)
l
400 650 mA
N-Channel Switch On Resistance V
IN2
= 2.4V 0.33
Ω
P-Channel Switch On Resistance V
IN2
= 2.4V 0.58
Ω
SW Leakage V
SHDN2
= 0V, V
SW2
= 0V or 5V, V
IN2
= 5.5V 0.20 2 μA
Note 4: Current is measured into the V
OUT
pin since the supply is
bootstrapped to the output for the step-up. The current will refl ect to the
input supply by: (V
OUT
/V
IN
) • Effi ciency. The outputs are not switching in
sleep.
Note 5: The LTC3523/LTC3523-2 are tested in a propriety test mode that
connects FB2 to the output of the error amplifi er.
Note 6: Specifi cation is guaranteed by design and not 100% tested in
production.
Note 7: Current measurements are performed when the LTC3523/
LTC3523-2 are not switching. The current limit values in operation will be
somewhat higher due to the propagation delay of the comparator.