LTC3557-1 Linear Technology, LTC3557-1 Datasheet - Page 5

• Manufacturer Part Number: LTC3557-1
• Description: USB Power Manager
• Manufacturer: Linear Technology

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SWITCHING REGULATOR ELECTRICAL CHARACTERISTICS
SYMBOL
Step-Down Switching Regulator 2
I
I
V
I
D2
R
R
R
V
I
V
t
Step-Down Switching Regulator 3
I
I
V
I
D3
R
R
R
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
specifi cations from 0°C to 85°C. Specifi cations 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 specifi ed maximum operating
junction temperature may result in device degradation or failure.
Note 4. V
The
V
VIN2
LIM2
FB2
⎯ R ⎯ S ⎯ T ⎯ 2
⎯ R ⎯ S ⎯ T ⎯ 2
VIN2
LIM3
FB3
FB2
⎯ R ⎯ S ⎯ T ⎯ 2
TH( ⎯ R ⎯ S ⎯ T ⎯ 2 )
FB3
P2
N2
SW2(PD)
P3
N3
SW3(PD)
OUT
●
= V
denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T
CC
IN1
is the greater of V
= V
PARAMETER
Pulse-Skip Mode Input Current (Note 11)
Burst Mode Input Current (Note 11)
Shutdown Input Current
Peak PMOS Current Limit
Feedback Voltage
FB2 Input Current (Note 11)
Maximum Duty Cycle
R
R
SW2 Pull-Down in Shutdown
Power-On ⎯ R ⎯ S ⎯ T ⎯ 2 Pin Output Low Voltage
Power-On ⎯ ⎯ R ⎯ S ⎯ T ⎯ 2 Pin Input Current (Note 11) V
Power-On ⎯ ⎯ R ⎯ S ⎯ T ⎯ 2 Pin Threshold
Power-On ⎯ R ⎯ S ⎯ T ⎯ 2 Pin Delay
Pulse-Skip Mode Input Current (Note 11)
Burst Mode Input Current (Note 11)
Shutdown Input current
Peak PMOS Current Limt
Feedback Voltage
FB3 Input Current (Note 11)
Maximum Duty Cycle
R
R
SW3 Pull-Down in Shutdown
DS(ON)
DS(0N)
DS(ON)
DS(ON)
IN2
= 3.8V, MODE = EN1 = EN2 = EN3 = 0V.
of NMOS
of PMOS
of PMOS
of NMOS
BUS
, V
OUT
or BAT.
CONDITIONS
I
I
I
EN2 = 3.8V, MODE = 0V or 3.8V (Note 7)
EN2 = 3.8V, MODE = 0V
EN2 = MODE = 3.8V
EN2 = 3.8V
FB2 = 0V, EN2 = 3.8V
EN2 = 3.8V
EN2 = 3.8V
EN2 = 0V
I
(Note 9)
From ⎯ ⎯ R ⎯ S ⎯ T ⎯ 2 Threshold to ⎯ ⎯ R ⎯ S ⎯ T ⎯ 2 Hi-Z
I
I
I
EN3 = 3.8V, MODE = 0V or 3.8V (Note 7)
EN3 = 3.8V, MODE = 0V
EN3 = MODE = 3.8V
EN3 = 3.8V
FB3 = 0V, EN3 = 3.8V
EN3 = 3.8V
EN3 = 3.8V
EN3 = 0V
OUT
OUT
OUT
⎯ ⎯ R ⎯ S ⎯ T ⎯ 2
OUT
OUT
OUT
⎯ ⎯ R ⎯ S ⎯ T ⎯ 2
= 0, EN2 = 3.8V, MODE = 0V
= 0, EN2 = MODE = 3.8V
= 0, EN2 = 0V, FB2 = 0V
= 0, EN3 = 3.8V, MODE = 0V
= 0, EN3 = MODE = 3.8V
= 0, EN3 = 0V, FB3 = 0V
= 1mA, FB2 = 0V, EN2 = 3.8V
= 5.5V, EN2 = 3.8V
Note 5. Total input current is the sum of quiescent current, I
measured current given by V
Note 6. h
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 specifi ed pin current rating may result in device
degradation or failure.
Note 8. Inductor series resistance adds to open-loop R
Note 9. ⎯ R ⎯ S ⎯ ⎯ T 2 threshold is expressed as a percentage difference from the
FB2 regulation voltage. The threshold is measured for FB2 rising.
Note 10. V
Note 11. FB high, not switching.
C/10
OUT
is expressed as a fraction of measured full charge current
not in UVLO.
LTC3557/LTC3557-1
CLPROG
●
●
●
●
–0.05
–0.05
0.78
0.78
0.78
0.78
/R
MIN
600
100
600
100
CLPROG
• (h
0.01
0.01
TYP
220
800
230
220
800
0.8
0.8
0.6
0.6
0.1
0.8
0.8
0.6
0.6
35
–8
35
10
10
CLPROG
OUT
+ 1)
0.824
0.824
MAX
1000
1000
0.82
0.05
0.35
0.82
0.05
.
A
50
50
1
1
1
BUSQ
= 25°C.
, and
UNITS
35571f
5
mA
mA
kΩ
ms
kΩ
μA
μA
μA
μA
μA
μA
μA
μA
μA
%
%
%
Ω
Ω
Ω
Ω
V
V
V
V
V