Datasheet
LTC3555/LTC3555-X
5
3555fd
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
SU_STD
Stop Condition Time 0.6 µs
t
HD_DAT(OUT)
Data Hold Time 225 ns
t
HD_DAT(IN)
Input Data Hold Time 0 900 ns
t
SU_DAT
Data Setup Time 100 ns
t
LOW
Clock Low Period 1.3 µs
t
HIGH
Clock High Period 0.6 µs
t
f
Clock Data Fall Time 20 300 ns
t
r
Clock Data Rise Time 20 300 ns
t
SP
Spike Suppression Time 50 ns
General Purpose Switching Regulators 1, 2 and 3
V
IN1,2,3
Input Supply Voltage 2.7 5.5 V
V
OUTUVLO
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
2.5 2.6
2.8
2.9
V
V
f
OSC
Oscillator Frequency 1.8 2.25 2.7 MHz
I
FB1,2,3
FBx Input Current V
FB1,2,3
= 0.85V –50 50 nA
D
1,2,3
Maximum Duty Cycle 100 %
R
SW1,2,3_PD
SWx Pull-Down in Shutdown 10 kΩ
General Purpose Switching Regulator 1
I
VIN1
Pulse Skip Mode Input Current
Burst Mode Input Current
Forced Burst Mode
®
Input Current
LDO Mode Input Current
Shutdown Input Current
I
OUT1
= 0µA (Note 6)
I
OUT1
= 0µA (Note 6)
I
OUT1
= 0µA (Note 6)
I
OUT1
= 0µA (Note 6)
I
OUT1
= 0µA, FB1 = 0V
225
35
20
20
60
35
35
1
µA
µA
µA
µA
µA
I
LIMSW1
PMOS Switch Current Limit Pulse Skip/Burst Mode Operation 600 800 1100 mA
I
OUT1
Available Output Current Pulse Skip/Burst Mode Operation (Note 7)
Forced Burst Mode Operation (Note 7)
LDO Mode (Note 7)
400
60
50
mA
mA
mA
V
FB1
V
FB1
Servo Voltage (Note 8)
l
0.78 0.80 0.82 V
R
P1
PMOS R
DS(ON)
0.6 Ω
R
N1
NMOS R
DS(ON)
0.7 Ω
R
LDO_CL1
LDO Mode Closed-Loop R
OUT
0.25 Ω
R
LDO_OL1
LDO Mode Open-Loop R
OUT
(Note 9) 2.5 Ω
General Purpose Switching Regulator 2
I
VIN2
Pulse Skip Mode Input Current
Burst Mode Input Current
Forced Burst Mode Input Current
LDO Mode Input Current
Shutdown Input 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
225
35
20
20
60
35
35
1
µA
µA
µA
µA
µA
I
LIMSW2
PMOS Switch Current Limit Pulse Skip/Burst Mode Operation 600 800 1100 mA
I
OUT2
Available Output Current Pulse Skip/Burst Mode Operation (Note 7)
Forced Burst Mode Operation (Note 7)
LDO Mode (Note 7)
400
60
50
mA
mA
mA
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, BAT = 3.8V, DV
CC
= 3.3V, R
PROG
= 1k, R
CLPROG
= 3k,
unless otherwise noted.
Burst Mode is a registered trademark of Linear Technology Corporation.