LTC3554 Datasheet, PDF (4/36 Pages) Linear Technology – Micropower USB Power Manager with Li-Ion Charger and Two Step-Down Regulators

LTC3554
SWITCHING REGULATOR ELECTRICAL CHARACTERISTICS
The l denotes specifications that apply over the full operating temperature range, otherwise specifications are at T_A = 25°C.
V_OUT = BVIN = 3.8V, PWR_ON1 = PWR_ON2 = 0V, unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
BVIN
Input Supply Voltage
l 2.7
5.5
V
V_OUT UVLO V_OUT Falling
V_OUT Rising
BVIN Connected to V_OUT Through Low
Impedance. V_OUT UVLO Disables the
Switching Regulators.
2.5
2.6
V
2.8
2.9
V
F_OSC
Oscillator Frequency
FSEL High
FSEL Low
1.91 2.25 2.59
MHz
0.955 1.125 1.295
MHz
I_FB1
FB1 Input Current (Note 8)
I_FB2
FB2 Input Current (Note 8)
R_{SW1_PD}
R_{SW2_PD}
SW1 Pull-Down in Shutdown
SW2 Pull-Down in Shutdown
Logic Input Pins (FSEL, STBY)
PWR_ON1 = 0V
PWR_ON2 = 0V
–0.05
–0.05
0.05
μA
0.05
μA
10
kΩ
10
kΩ
Input High Voltage
0.8
1.2
V
Input Low Voltage
0.4
0.7
V
Input Current
–1
1
μA
Switching Regulator 1 in Normal Operation (STBY Low)
I_LIM1
Peak PMOS Current Limit
V_FB1
Regulated Feedback Voltage
D1
Max Duty Cycle
PWR_ON1 = 3.8V (Note 7)
PWR_ON1 = 3.8V
300 400
500
mA
l 780 800
820
mV
100
%
R_P1
R_DS(ON) of PMOS
R_N1
R_DS(ON) of NMOS
Switching Regulator 1 in Standby Mode (STBY High)
I_SW1 = 100mA
I_SW1 = –100mA
1.1
Ω
0.7
Ω
V_{FB1_LOW}
Feedback Voltage Threshold
PWR_ON1 = 3.8V, V_FB1 Falling
l 770 800
820
mV
I_{SHORT1_SB} Short-Circuit Current
15
25
50
mA
V_{DROP1_SB} Standby Mode Dropout Voltage
PWR_ON1 = 2.9V, I_SW1 = 5mA, V_FB1 = 0.77V,
V_OUT = 2.9V, BVIN = 2.9V
30
60
mV
Switching Regulator 2 in Normal Operation (STBY Low)
I_LIM2
Peak PMOS Current Limit
V_FB2
Regulated Feedback Voltage
D2
Max Duty Cycle
PWR_ON2 = 3.8V (Note 7)
PWR_ON2 = 3.8V
300 400
500
mA
l 780 800
820
mV
100
%
R_P2
R_DS(ON) of PMOS
I_SW2 = 100mA
1.1
Ω
R_N2
R_DS(ON) of NMOS
Switching Regulator 2 in Standby Mode (STBY High)
I_SW2 = –100mA
0.7
Ω
V_{FB2_LOW}
I_{SHORT2_SB}
V_{DROP2_SB}
Feedback Voltage Threshold
Short-Circuit Current
Standby Mode Dropout Voltage
PWR_ON2 = 3.8V, V_FB2 Falling
l 770 800
820
mV
15
25
50
mA
PWR_ON2 = 2.9V, I_SW2 = 5mA, V_FB2 = 0.77V,
V_OUT = 2.9V, BVIN = 2.9V
30
60
mV
3554p
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