Datasheet

LTC3542
3
3542fa
TYPICAL PERFORMANCE CHARACTERISTICS
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. No pin should exceed 6V.
Note 2: The LTC3542 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. The LTC3542I is guaranteed over the full
–40°C to 125°C operating temperature range.
Note 3: Failure to solder the Exposed Pad of the package to the PC board
will result in a thermal resistance much higher than 102°C/W.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
S
Input DC Supply Current (Note 5)
Active Mode
Sleep Mode
Shutdown
V
FB
= 0.5V
V
FB
= 0.7V, MODE = 0V
RUN = 0V
26
0.1
500
35
1
μA
μA
μA
f
OSC
Oscillator Frequency V
FB
= 0.6V
●
1.8 2.25 2.7 MHz
f
SYNC
Synchronous Frequency V
FB
= 0.6V 1 3 MHz
I
LIM
Peak Switch Current V
IN
= 3V, V
FB
= 0.5V, Duty Cycle < 35% 650 1000 mA
R
DS(ON)
P-Channel On Resistance (Note 6)
N-Channel On Resistance (Note 6)
I
SW
= 100mA
I
SW
= –100mA
0.5
0.35
0.65
0.55
Ω
Ω
I
SW(LKG)
Switch Leakage Current V
IN
= 5V, V
RUN
= 0V, V
SW
= 0V or 5V ±0.01 ±1 μA
V
UVLO
Undervoltage Lockout Threshold V
IN
Rising
V
IN
Falling 1.8
2.0
1.9
2.3 V
V
V
RUN
RUN Threshold
●
0.3 1.5 V
I
RUN
RUN Leakage Current
●
±0.01 ±1 μA
V
MODE/SYNC
MODE/SYNC Threshold
●
0.3 1.2 V
I
MODE/SYNC
MODE/SYNC Leakage Current
●
±0.01 ±1 μA
Note 4: The converter is tested in a proprietary test mode that connects
the output of the error amplifi er to the SW pin, which is connected to an
external servo loop.
Note 5: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 6: The DFN switch on resistance is guaranteed by correlation to wafer
level measurements.
Note 7: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
) • (θ
JA
).
Burst Mode Operation Pulse Skip Mode Operation Start-Up from Shutdown
SW
2V/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 25mA
FIGURE 3a CIRCUIT
2μs/DIV
3542 G01
V
OUT
50mV/DIV
AC COUPLED
I
L
100mA/DIV
SW
2V/DIV
I
L
100mA/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 25mA
FIGURE 3a CIRCUIT
400ns/DIV
3542 G02
V
OUT
50mV/DIV
AC COUPLED
RUN
2V/DIV
I
L
100mA/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 0A
FIGURE 3a CIRCUIT
400μs/DIV
3542 G03
V
OUT
1V/DIV
T
A
= 25°C unless otherwise specifi ed.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 3.6V unless otherwise noted.