Datasheet

LTC3553
4
3553fb
BUCK REGULATOR ELECTRICAL CHARACTERISTICS
The l denotes specifi cations that apply over the full operating temperature range, otherwise specifi cations are at T
A
= 25°C (Note 2).
BUCK_ON = V
OUT
= BVIN = 3.8V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
BVIN Input Supply Voltage (Note 9)
l
2.7 5.5 V
V
OUT
UVLO V
OUT
Undervoltage Lockout V
OUT
Falling
V
OUT
Rising
2.5 2.6
2.8 2.9
V
V
f
OSC
Oscillator Frequency 0.955 1.125 1.295 MHz
I
BUCK_FB
BUCK_FB Input Current (Note 8) –0.05 0.05 µA
R
SW_PD
SW Pull-Down in Shutdown BUCK_ON = 0V 10 k
Logic Input Pin (STBY)
Input High Voltage 1.2 V
Input Low Voltage 0.4 V
Input Current –1 1 µA
Buck Regulator in Normal Operation (STBY Low)
I
LIM
Peak PMOS Current Limit BUCK_ON = 3.8V (Note 7) 300 500 650 mA
V
BUCK_FB
Regulated Feedback Voltage BUCK_ON = 3.8V
l
780 800 820 mV
D
MAX
Max Duty Cycle 100 %
R
P
R
DS(ON)
of PMOS I
SW
= 100mA 1.1 
R
N
R
DS(ON)
of NMOS I
SW
= –100mA 0.7 
Buck Regulator in Standby Mode (STBY High)
Feedback Voltage Threshold BUCK_ON = 3.8V, V
BUCK_FB
Falling
l
770 800 820 mV
Short-Circuit Current 30 50 100 mA
Standby Mode Dropout Voltage BUCK_ON = 2.9V, I
SW
= 10mA, V
BUCK_FB
= 0.76V,
V
OUT
= 2.9V, BVIN = 2.9V
50 100 mV
POWER MANAGER ELECTRICAL CHARACTERISTICS
The l denotes specifi cations that apply over the full operating temperature range, otherwise specifi cations are at T
A
= 25°C (Note 2),
V
BUS
= 5V, V
BAT
= 3.8V, HPWR = SUSP = BUCK_ON = LDO_ON = 0V, R
PROG
= 1.87k, STBY = high, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Ideal Diode
V
FWD
Forward Voltage Detection (Note 12) 15 mV
R
DROPOUT
Diode On-Resistance, Dropout I
OUT
= 200mA, V
BUS
= 0V 240 m
I
MAX
Diode Current Limit (Note 7) 1 A
Logic Inputs (HPWR, SUSP)
V
IL
Input Low Voltage 0.4 V
V
IH
Input High Voltage 1.2 V
R
PD
Internal Pull-Down Resistance 4M
Logic Output (CHRG)
V
OL
Output Low Voltage I
CHRG
= 5mA 65 250 mV
I
CHRG
Output Hi-Z Leakage Current V
BAT
= 4.5V, V
CHRG
= 5V 0 1 µA