Datasheet

LTC3520
3
3520fa
PARAMETER CONDITIONS MIN TYP MAX UNITS
Feedback Voltage (FB2 Pin) (Note 4)
l
0.771 0.790 0.809 V
Feedback Input Current (FB2 Pin) 150 nA
PMOS Current Limit (Note 3)
l
0.8 1.25 A
Maximum Duty Cycle V
FB2
= 0.72V
l
100 %
Minimum Duty Cycle V
FB2
= 0.88V
l
0%
Soft-Start Charging Current 6μA
SD2 Input High Voltage 1.4 V
SD2 Input Low Voltage 0.4 V
SD2 Input Current 0.01 1 μA
Buck-Boost Converter
Output Voltage
l
2.2 5.25 V
PMOS Switch Resistance 0.20
Ω
NMOS Switch Resistance 0.15
Ω
NMOS Switch Leakage V
SW1A
= V
SW1B
= 5V, S
VIN
= P
VIN1
= P
VIN2
= P
VIN3
= 5V 0.1 5 μA
PMOS Switch Leakage V
SW1A
= V
SW1B
= 0V, S
VIN
= P
VIN1
= P
VIN2
= P
VIN3
= 5V 0.1 10 μA
Feedback Voltage (FB1 Pin)
l
0.766 0.782 0.798 V
Feedback Input Current (FB1 Pin) 150 nA
Forward Current Limit (Note 3)
LTC3520E
LTC3520I
l
l
1.4
1.25
2
1.85
A
A
Reverse Current Limit (Note 3) 560 mA
Burst Mode Operation Current Limit (Note 3) 325 mA
Error Amplifi er Gain 80 dB
Error Amplifi er Sink Current 500 μA
Error Amplifi er Source Current 14 μA
Maximum Duty Cycle Boost (% Switch C is On)
Buck (% Switch A is On)
l
70
100
80 %
%
Minimum Duty Cycle
l
0%
Soft-Start Charging Current 6μA
SD1, PWM1 Input High Voltage 1.4 V
SD1, PWM1 Input Low Voltage 0.4 V
SD1, PWM1 Input Current 0.01 1 μA
Gain Block
Quiescent Current V
AIN
= 0.88V, V
SD1
= V
SD2
= 0V 45 μA
A
IN
Pin Threshold Voltage
l
0.770 0.786 0.802 V
A
IN
Pin Input Bias Current 150 nA
A
OUT
Sink Current V
AIN
= 0.72V, V
AOUT
= 1.8V 17 mA
A
OUT
Source Current V
AIN
= 0.88V, V
AOUT
= 1.8V 18 μA
A
OUT
Pin Voltage V
AIN
= 0.72V, I
AOUT
= 1mA 25 150 mV
Open Loop Gain 80 dB
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
junction temperature range, otherwise specifi cations are at T
A
= 25°C, S
VIN
= P
VIN1
= P
VIN2
= P
VIN3
= 3.6V, V
OUT1
= 3.3V, R
T
= 54.9k,
unless otherwise noted.