LTC3549 Datasheet, PDF (3/16 Pages) Linear Technology – 250mA Low VIN Buck Regulator in 2mm × 3mm DFN

LTC3549
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C, V_IN = 2.2V.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
I_S
f_OSC
t_SS
R_PFET
R_NFET
I_LSW
Input DC Bias Current
Active Mode
Sleep Mode
Shutdown
Nominal Oscillator Frequency
Soft-Start Period
R_DS(ON) of P-Channel FET
R_DS(ON) of N-Channel FET
SW Leakage
(Note 5)
V_OUT = 90%, I_LOAD = 0A
V_OUT = 103%, I_LOAD = 0A
V_RUN = 0V, V_IN = 5.5V
300 475
µA
50
95
µA
0.1
5
µA
● 1.8
2.25
2.7
MHz
RUN↑
1
ms
I_SW = 100mA, Wafer Level
I_SW = 100mA, DD Package (Note 7)
I_SW = 100mA, Wafer Level
I_SW = 100mA, DD Package (Note 7)
V_RUN = 0V, V_SW = 0V or 5.5V, V_IN = 5.5V
0.5
Ω
0.56
Ω
0.35
Ω
0.4
Ω
±0.1
±1
µA
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 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: 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
becomes active at a junction temperature greater than the maximum
operating junction temperature. Continuous operation above the specified
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 amplifier.
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.
3549f
3