LTC3407A-2 Linear Technology, LTC3407A-2 Datasheet - Page 6

• Manufacturer Part Number: LTC3407A-2
• Description: Dual Synchronous 800mA2.25MHz Step-Down DC/DC Regulator
• Manufacturer: Linear Technology

LTC3407A-2
PI FU CTIO S
BLOCK DIAGRA
6
V
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
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
to GND.
SW1 (Pin 4): Regulator 1 Switch Node Connection to the
Inductor. This pin swings from V
GND (Pin 5): Main Ground. Connect to the (–) terminal of
C
MODE/SYNC (Pin 6): Combination Mode Selection and
Oscillator Synchronization. This pin controls the operation
of the device. When tied to V
operation or pulse skipping mode is selected, respec-
tively. Do not float this pin. The oscillation frequency can
FB1
IN
OUT
U
(Pin 3): Main Power Supply. Must be closely decoupled
, and (–) terminal of C
(Pin 1): Output Feedback. Receives the feedback
MODE/SYNC
U
RUN/SS1
RUN/SS2
V
V
FB1
FB2
10
2
9
6
1
IN
U
enables regulator 1, while forcing it
REGULATOR 1
REGULATOR 2 (IDENTICAL TO REGULATOR 1)
0.6V REF
0.55V
0.65V
0.6V
W
SHUTDOWN
IN
.
+
–
–
+
+
–
IN
UVDET
OVDET
OSC
IN
EA
or GND, Burst Mode
to GND.
I
UV
OV
TH
OSC
SLOPE
COMP
0.65V
S
R
LATCH
–
+
RS
BURST
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
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
cycles when both channels are within regulation.
RUN/SS2 (Pin 9): Regulator 2 Enable and Soft-Start Input.
Forcing this pin to V
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
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
soldered to electrical ground on PCB.
Q
Q
FB2
EN
SWITCHING
BLANKING
COUNTER
CIRCUIT
(Pin 10): Output Feedback. Receives the feedback
SLEEP
LOGIC
POR
AND
PGOOD2
PGOOD1
–
I
COMP
SHOOT-
I
THRU
ANTI
RCMP
+
IN
+
–
OUT
CLAMP
BURST
enables regulator 2, while forcing it
, and (–) terminal of C
5Ω
w w w . D a t a S h e e t 4 U . c o m
IN
to GND.
V
IN
3407A2 BD
V
IN
11
4
3
8
5
7
SW1
GND
V
POR
GND
SW2
IN
IN
. Must be
16
clock
3407a2f