LTC3557_15 Datasheet, PDF (5/28 Pages) Linear Technology – USB Power Manager with Li-Ion Charger and Three Step-Down Regulators

LTC3557/LTC3557-1
SWITCHING REGULATOR ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T_A = 25°C.
V_OUT = V_IN1 = V_IN2 = 3.8V, MODE = EN1 = EN2 = EN3 = 0V.
SYMBOL PARAMETER
CONDITIONS
Step-Down Switching Regulator 2
I_VIN2
Pulse-Skip Mode Input Current (Note 10) I_OUT = 0, EN2 = 3.8V, MODE = 0V
Burst Mode Input Current (Note 10)
I_OUT = 0, EN2 = MODE = 3.8V
Shutdown Input Current
I_OUT = 0, EN2 = 0V, FB2 = 0V
I_LIM2
Peak PMOS Current Limit
EN2 = 3.8V, MODE = 0V or 3.8V (Note 7)
V_FB2
Feedback Voltage
EN2 = 3.8V, MODE = 0V
EN2 = MODE = 3.8V
I_FB2
FB2 Input Current (Note 10)
D2
Maximum Duty Cycle
EN2 = 3.8V
FB2 = 0V, EN2 = 3.8V
R_P2
R_N2
R_SW2(PD)
V_RST2
I_RST2
V_TH(RST2)
t_RST2
R_DS(ON) of PMOS
EN2 = 3.8V
R_DS(0N) of NMOS
EN2 = 3.8V
SW2 Pull-Down in Shutdown
EN2 = 0V
Power-On RST2 Pin Output Low Voltage I_RST2 = 1mA, FB2 = 0V, EN2 = 3.8V
Power-On RST2 Pin Input Current (Note 10) V_RST2 = 5.5V, EN2 = 3.8V
Power-On RST2 Pin Threshold
(Note 8)
Power-On RST2 Pin Delay
From RST2 Threshold to RST2 Hi-Z
Step-Down Switching Regulator 3
I_VIN2
Pulse-Skip Mode Input Current (Note 10) I_OUT = 0, EN3 = 3.8V, MODE = 0V
Burst Mode Input Current (Note 10)
I_OUT = 0, EN3 = MODE = 3.8V
Shutdown Input current
I_OUT = 0, EN3 = 0V, FB3 = 0V
I_LIM3
Peak PMOS Current Limt
EN3 = 3.8V, MODE = 0V or 3.8V (Note 7)
V_FB3
Feedback Voltage
EN3 = 3.8V, MODE = 0V
EN3 = MODE = 3.8V
I_FB3
FB3 Input Current (Note 10)
D3
Maximum Duty Cycle
EN3 = 3.8V
FB3 = 0V, EN3 = 3.8V
R_P3
R_N3
R_SW3(PD)
R_DS(ON) of PMOS
R_DS(ON) of NMOS
SW3 Pull-Down in Shutdown
EN3 = 3.8V
EN3 = 3.8V
EN3 = 0V
MIN
TYP
MAX UNITS
220
μA
35
50
μA
0.01
1
μA
600
800 1000
mA
● 0.78
0.8
0.82
V
● 0.78
0.8 0.824
V
−0.05
0.05
μA
100
%
0.6
Ω
0.6
Ω
10
kΩ
0.1
0.35
V
1
μA
−8
%
230
ms
220
μA
35
50
μA
0.01
1
μA
600
800 1000
mA
● 0.78
0.8
0.82
V
● 0.78
0.8 0.824
V
−0.05
0.05
μA
100
%
0.6
Ω
0.6
Ω
10
kΩ
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 LTC3557/LTC3557-1 is guaranteed to meet performance
specifications from 0°C to 85°C. Specifications over the −40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 3. This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperatures will exceed 110°C when overtemperature protection is
active. Continuous operation above the specified maximum operating
junction temperature may result in device degradation or failure.
Note 4. V_CC is the greater of V_BUS, V_OUT or BAT.
Note 5. Total input current is the sum of quiescent current, I_BUSQ, and
measured current given by V_CLPROG/R_CLPROG • (h_CLPROG + 1)
Note 6. h_C/10 is expressed as a fraction of measured full charge current
with indicated PROG resistor.
Note 7. The current limit features of this part are intended to protect the
IC from short term or intermittent fault conditions. Continuous operation
above the maximum specified pin current rating may result in device
degradation or failure.
Note 8. RST2 threshold is expressed as a percentage difference from the
FB2 regulation voltage. The threshold is measured for FB2 rising.
Note 9. V_OUT not in UVLO.
Note 10. FB high, not switching.
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