LTC3556_15 Datasheet, PDF (5/36 Pages) Linear Technology – High Effi ciency USB Power Manager with Dual Buck and Buck-Boost DC/DCs

LTC3556
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C. V_BUS = 5V, V_IN1 = V_IN2 = V_IN3 = V_OUT3 = 3.8V, BAT = 3.8V, DV_CC = 3.3V,
R_PROG = 1k, R_CLPROG = 3.01k, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
t_{HD_DAT(I)}
Data Hold Time Input
t_{SU_DAT}
Data Setup Time
t_LOW
SCL Clock Low Period
t_HIGH
SCL Clock High Period
t_f
Clock/Data Fall Time
t_r
Clock/Data Rise Time
t_SP
Input Spike Suppression Pulse Width
Switching Regulators 1, 2 and 3
C_B = Capacitance of One BUS Line (pF)
C_B = Capacitance of One BUS Line (pF)
0
100
1.3
0.6
20 + 0.1C_B
20 + 0.1C_B
ns
ns
μs
μs
300
ns
300
ns
50
ns
V_IN1,2,3
V_OUTUVLO
Input Supply Voltage
V_OUT UVLO—V_OUT Falling
V_OUT UVLO—V_OUT Rising
V_IN1,2,3 Connected to V_OUT Through Low
Impedance. Switching Regulators are
Disabled in UVLO
2.7
5.5
V
2.5
2.6
V
2.8 2.9
V
f_OSC
Oscillator Frequency
Switching Regulator 1 (Buck)
l
1.8
2.25 2.7
MHz
I_VIN1
Pulse Skip Mode Input Current
I_OUT1 = 0μA (Note 6)
Burst Mode^® Input Current
I_OUT1 = 0μA (Note 6)
Forced Burst Mode Input Current
I_OUT1 = 0μA (Note 6)
LDO Mode Input Current
I_OUT1 = 0μA (Note 6)
Shutdown Input Current
I_OUT1 = 0μA, FB1 = 0V
225 400
μA
35
60
μA
20
35
μA
20
35
μA
1
μA
I_LIM1
PMOS Switch Current Limit
Pulse Skip/Burst Mode Operation
600
800 1100
mA
I_OUT1
Available Output Current
Pulse Skip/Burst Mode Operation (Note 9)
400
mA
Forced Burst Mode Operation (Note 9)
60
mA
LDO Mode (Note 9)
50
mA
V_FBHIGH1
V_FBLOW1
V_LSB1
R_P1
R_N1
R_{LDO_CL1}
R_{LDO_OL1}
I_FB1
D1
Maximum Servo Voltage
Minimum Servo Voltage
V_FB1 Servo Voltage Step Size
PMOS R_DS(ON)
NMOS R_DS(ON)
LDO Mode Closed-Loop R_OUT
LDO Mode Open-Loop R_OUT
FB1 Input Current
Maximum Duty Cycle
Full Scale (1, 1, 1, 1) (Note 7)
Zero Scale (0, 0, 0, 0) (Note 7)
(Note 8)
V_FB1 = 0.85V
l 0.780 0.800 0.820
V
l 0.405 0.425 0.445
V
25
mV
0.6
Ω
0.7
Ω
0.25
Ω
2.5
Ω
–50
50
nA
l 100
%
R_SW1
SW1 Pull-Down in Shutdown
Switching Regulator 2 (Buck)
10
kΩ
I_VIN2
I_LIM2
I_OUT2
Pulse Skip Mode Input Current
Burst Mode Input Current
Forced Burst Mode Input Current
LDO Mode Input Current
Shutdown Input Current
PMOS Switch Current Limit
Available Output Current
I_OUT2 = 0μA (Note 6)
I_OUT2 = 0μA (Note 6)
I_OUT2 = 0μA (Note 6)
I_OUT2 = 0μA (Note 6)
I_OUT2 = 0μA, FB2 = 0V
Pulse Skip/Burst Mode Operation
Pulse Skip/Burst Mode Operation (Note 9)
Forced Burst Mode Operation (Note 9)
LDO Mode (Note 9)
225 400
μA
35
60
μA
20
35
μA
20
35
μA
1
μA
600
800 1100
mA
400
mA
60
mA
50
mA
Burst Mode is a registered trademark of Linear Technology Corporation.
3556f
5