LTC3407A-2
6
3407a2f
be synchronized to an external oscillator applied to this pin
and pulse skipping mode is automatically selected.
SW2 (Pin 7): Regulator 2 Switch Node Connection to the
Inductor. This pin swings from V
IN
to GND.
POR (Pin 8): Power-On Reset. This common-drain logic
output is pulled to GND when the output voltage is not
within ±8.5% of regulation and goes high after 2
16
clock
cycles when both channels are within regulation.
RUN/SS2 (Pin 9): Regulator 2 Enable and Soft-Start Input.
Forcing this pin to V
IN
enables regulator 2, while forcing it
to GND causes regulator 2 to shut down. Connect external
RC-Network with desired time-constant to enable soft-
start feature. This pin must be driven; do not float.
V
FB2
(Pin 10): Output Feedback. Receives the feedback
voltage from the external resistive divider across the
output. Nominal voltage for this pin is 0.6V.
Exposed Pad (GND) (Pin 11): Power Ground. Connect to
the (–) terminal of C
OUT
, and (–) terminal of C
IN
. Must be
soldered to electrical ground on PCB.
1
2
9
10
8
3
4
11
5
–
+
–
+
–
+
–
+
EA
UVDET
OVDET
0.6V
7
0.65V
0.55V
–
+
0.65V
UV
OV
I
TH
SWITCHING
LOGIC
AND
BLANKING
CIRCUIT
S
R
Q
Q
RS
LATCH
BURST
–
+
I
COMP
I
RCMP
ANTI
SHOOT-
THRU
BURST
CLAMP
SLOPE
COMP
EN
SLEEP
POR
COUNTER
0.6V REF OSC
OSC
REGULATOR 2 (IDENTICAL TO REGULATOR 1)
PGOOD1
PGOOD2
SHUTDOWN
V
IN
V
IN
V
IN
6
REGULATOR 1
SW1
GND
POR
GND
SW2
3407A2 BD
5Ω
MODE/SYNC
V
FB1
RUN/SS1
RUN/SS2
V
FB2
V
FB1
(Pin 1): Output Feedback. Receives the feedback
voltage from the external resistive divider across the
output. Nominal voltage for this pin is 0.6V.
RUN/SS1 (Pin 2): Regulator 1 Enable and Soft-Start Input.
Forcing this pin to V
IN
enables regulator 1, while forcing it
to GND causes regulator 1 to shut down. Connect external
RC-network with desired time-constant to enable soft-
start feature. This pin must be driven; do not float.
V
IN
(Pin 3): Main Power Supply. Must be closely decoupled
to GND.
SW1 (Pin 4): Regulator 1 Switch Node Connection to the
Inductor. This pin swings from V
IN
to GND.
GND (Pin 5): Main Ground. Connect to the (–) terminal of
C
OUT
, and (–) terminal of C
IN
.
MODE/SYNC (Pin 6): Combination Mode Selection and
Oscillator Synchronization. This pin controls the operation
of the device. When tied to V
IN
or GND, Burst Mode
operation or pulse skipping mode is selected, respec-
tively. Do not float this pin. The oscillation frequency can
BLOCK DIAGRA
W
PI FU CTIO S
UUU
