LTC3411
4
3411fb
PIN FUNCTIONS
SHDN/R
T
(Pin 1): Combination Shutdown and Timing
Resistor Pin. The oscillator frequency is programmed by
connecting a resistor from this pin to ground. Forcing
this pin to SV
IN
causes the device to be shut down. In
shutdown all functions are disabled.
SYNC/MODE (Pin 2): Combination Mode Selection and
Oscillator Synchronization Pin. This pin controls the op-
eration of the device. When tied to SV
IN
or SGND, Burst
Mode operation or pulse skipping mode is selected,
respectively. If this pin is held at half of SV
IN
, the forced
continuous mode is selected. The oscillation frequency
can be syncronized to an external oscillator applied to
this pin. When synchronized to an external clock pulse
skip mode is selected.
SGND (Pin 3): The Signal Ground Pin. All small signal
components and compensation components should be
connected to this ground (see Board Layout Consider-
ations).
SW (Pin 4): The Switch Node Connection to the Inductor.
This pin swings from PV
IN
to PGND.
PGND (Pin 5): Main Power Ground Pin. Connect to the
(–) terminal of C
OUT
, and (–) terminal of C
IN
.
PV
IN
(Pin 6): Main Supply Pin. Must be closely decoupled
to PGND.
SV
IN
(Pin 7): The Signal Power Pin. All active circuitry
is powered from this pin. Must be closely decoupled to
SGND. SV
IN
must be greater than or equal to PV
IN
.
PGOOD (Pin 8): The Power Good Pin. This common drain
logic output is pulled to SGND when the output voltage is
not within ±7.5% of regulation.
V
FB
(Pin 9): Receives the feedback voltage from the ex-
ternal resistive divider across the output. Nominal voltage
for this pin is 0.8V.
I
TH
(Pin 10): Error Amplifi er Compensation Point. The
current comparator threshold increases with this control
voltage. Nominal voltage range for this pin is 0V to 1.5V.
