lt3493edcb-3 Linear Technology Corporation, lt3493edcb-3 Datasheet - Page 6

• Manufacturer Part Number: lt3493edcb-3
• Description: 1.2a, 750khz Step-down Switching Regulator In 2mm X 3mm Dfn
• Manufacturer: Linear Technology Corporation

ON OFF
LT3493-3
PI FU CTIO S
FB (Pin 1): The LT3493-3 regulates its feedback pin to
780mV. Connect the feedback resistor divider tap to this
pin. Set the output voltage according to V
(1 + R1/R2). A good value for R2 is 10k.
GND (Pin 2): Tie the GND pin to a local ground plane below
the LT3493-3 and the circuit components. Return the
feedback divider to this pin.
BOOST (Pin 3): The BOOST pin is used to provide a drive
voltage, higher than the input voltage, to the internal
bipolar NPN power switch.
SW (Pin 4): The SW pin is the output of the internal power
switch. Connect this pin to the inductor, catch diode and
boost capacitor.
BLOCK DIAGRA
6
V
U
IN
R3
C2
C4
U
5
6
V
SHDN
IN
U
INT REG
UVLO
AND
W
OSC
FREQUENCY
FOLDBACK
SLOPE
COMP
Σ
2
V
GND
C
OUT
= 0.78V •
g
m
R
S
Q
Q
780mV
V
internal regulator and to the internal power switch. This
pin must be locally bypassed.
SHDN (Pin 6): The SHDN pin is used to put the LT3493-
3 in shutdown mode. Tie to ground to shut down the
LT3493-3. Tie to 2.3V or more for normal operation. If the
shutdown feature is not used, tie this pin to the V
SHDN also provides a soft-start function; see the Applica-
tions Information section.
Exposed Pad (Pin 7): The Exposed Pad must be soldered
to the PCB and electrically connected to ground. Use a
large ground plane and thermal vias to optimize thermal
performance.
IN
R2
(Pin 5): The V
1
FB
R1
DRIVER
IN
pin supplies current to the LT3493-3’s
Q1
BOOST
SW
3
4
D1
C3
D2
L1
C1
3493-3 BD
IN
3493-3f
pin.
V
OUT