Datasheet

LTC3549
3
3549f
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. Voltage on any pin may not exceed 6V.
Note 2: The LTC3549E 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: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC3549: T
J
= T
A
+ (P
D
)(64°C/W)
This IC includes overtemperature protection that is intended to protect the
device during momentary overload conditions. Overtemperature protection
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
S
Input DC Bias Current
Active Mode
Sleep Mode
Shutdown
(Note 5)
V
OUT
= 90%, I
LOAD
= 0A
V
OUT
= 103%, I
LOAD
= 0A
V
RUN
= 0V, V
IN
= 5.5V
300
50
0.1
475
95
5
µA
µA
µA
f
OSC
Nominal Oscillator Frequency
●
1.8 2.25 2.7 MHz
t
SS
Soft-Start Period RUN↑ 1ms
R
PFET
R
DS(ON)
of P-Channel FET I
SW
= 100mA, Wafer Level
I
SW
= 100mA, DD Package (Note 7)
0.5
0.56
Ω
Ω
R
NFET
R
DS(ON)
of N-Channel FET I
SW
= 100mA, Wafer Level
I
SW
= 100mA, DD Package (Note 7)
0.35
0.4
Ω
Ω
I
LSW
SW Leakage V
RUN
= 0V, V
SW
= 0V or 5.5V, V
IN
= 5.5V ±0.1 ±1 µA
The ● denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C, V
IN
= 2.2V.
ELECTRICAL CHARACTERISTICS
becomes active at a junction temperature greater than the maximum
operating junction temperature. Continuous operation above the specifi ed
maximum operating junction temperature may impair device reliability.
Note 4: The LTC3549 is tested in a proprietary test mode that connects V
FB
to the output of the error amplifi er.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 6: ΔV
OVL
is the amount V
FB
must exceed the regulated feedback
voltage.
Note 7: Determined by design, not production tested.