LTC3441
5
3441fc
For more information www.linear.com/LTC3441
Typical perForMance characTerisTics
NMOS R
DS(ON)
PMOS R
DS(ON)
Minimum Start Voltage
TEMPERATURE (°C)
–55
0.05
DS(ON)
0.07
0.09
0.11
0.13
0.15
–25
5 35 65
3441 G14
95 125
V
IN
= V
OUT
= 3.6V
SWITCHES B AND C
TEMPERATURE (°C)
–50
0.05
PMOS R
DS(ON)
(Ω)
0.07
0.09
0.11
–25
5
35 65
3441 G15
95
0.13
0.06
0.08
0.10
0.12
0.14
125
V
IN
= V
OUT
= 3.6V
SWITCHES A AND D
TEMPERATURE (°C)
–55
2.10
MINIMUM START VOLTAGE (V)
2.15
2.20
2.25
–25 5 35 65
3441 G16
95 125
pin FuncTions
SHDN/SS (Pin 1): Combined Soft-Start and Shutdown.
Applied voltage < 0.4V shuts down the IC. Tie to >1.4V to
enable the IC and >2.4V to ensure the error amp is not
clamped from soft-start. An RC from the shutdown com-
mand signal to this pin will provide a soft-start function
by limiting the rise time of the V
C
pin.
GND (Pin 2): Signal Ground for the IC.
PGND (Pins 3, 6, 13 Exposed Pad): Power Ground for
the Internal NMOS Power Switches
SW1 (Pin 4): Switch pin where the internal switches A
and B are connected. Connect inductor from SW1 to SW2.
An optional Schottky diode can be connected from this
SW1 to ground. Minimize trace length to keep EMI down.
SW2 (Pin 5): Switch pin where the internal switches C
and D are connected. An optional Schottky diode can
be connected from SW2 to V
OUT
(it is required where
V
OUT
> 4.3V). Minimize trace length to keep EMI down.
MODE/SYNC (Pin 7): Burst Mode Select and Oscillator
Synchronization.
MODE/SYNC = High: Enable Burst Mode Operation.
During the period where the IC is supplying energy to
the output, the inductor peak inductor current will reach
0.8A and return to zero current on each cycle. In Burst
Mode operation the operation is variable frequency,
which provides a significant efficiency improvement at
light loads. The Burst Mode operation will continue until
the pin is driven low.
MODE/SYNC
= Low: Disable Burst Mode operation
and maintain low noise, constant frequency operation .
MODE/SYNC = External CLK : Synchronization of the
internal oscillator and Burst Mode operation disable. A
clock pulse width between 100ns and 2µs and a clock
frequency between 2.3MHz and 3.4MHz (twice the
desired frequency) is required to synchronize the IC.
f
OSC
= f
SYNC
/2
V
OUT
(Pin 8): Output of the Synchronous Rectifier. A filter
capacitor is placed from V
OUT
to GND. A ceramic bypass
capacitor is recommended as close to the V
OUT
and GND
pins as possible.
PV
IN
(Pin 9): Power V
IN
Supply Pin. A 10µF ceramic ca-
pacitor is recommended as close to the PV
IN
and PGND
pins as possible
