Datasheet

LTC3823
8
3823fd
PIN FUNCTIONS
(UH/GN)
PGND (Pin 22/Pin 22): Power Ground. Connect this pin
closely to the source of the bottom N-channel MOSFET,
the (–) terminal of C
VCC
and C
IN
.
SENSE
–
(Pin 23/Pin 23): Current Sense Comparator In-
put. The negative input to the current comparator is used
to accurately Kelvin sense the bottom side of the sense
resistor or MOSFET.
SENSE
+
(Pin 24/Pin 24): Current Sense Comparator
Input. The positive input to the current comparator is
normally connected to the SW node unless using a sense
resistor.
SW (Pin 25/Pin 25): Switch Node. The (–) terminal of the
bootstrap capacitor, C
B
, connects here. This pin swings
from a diode drop below ground up to V
IN
.
TG (Pin 26/Pin 26): Top Gate Drive Output. This pin drives
the top N-channel MOSFET with a voltage swing equal to
INTV
CC
, superimposed on the switch node voltage SW.
BOOST (Pin 27/Pin 27): Boosted Floating Driver Supply.
The (+) terminal of the bootstrap capacitor, C
B
, connects
here. This pin swings from a diode voltage drop below
INTV
CC
up to V
IN
+ INTV
CC
.
Z0 (Pin 28/Pin 28): Dead Time Control Input. Applying a
DC voltage at this pin will vary the dead time between TG
low and BG high transition. Do not force a voltage higher
than INTV
CC
on this pin.
FCB (Pin 29/Pin 1): Forced Continuous Input. Connect
this pin to SGND to forced continuous synchronization
operation at low load, to INTV
CC
to enable discontinuous
mode operation at low load, or to a resistive divider from
a secondary output when using a secondary winding.
RUN (Pin 30/Pin 2): Run Control Input. A voltage above
1.5V turns on the IC. Forcing this pin below 1.5V shuts
down the device.
V
ON
(Pin 31/Pin 3): On-Time Input. Connecting this pin
to the output voltage makes the on-time proportional to
V
OUT
. The comparator input defaults to 0.6V when the
pin is grounded and defaults to 4.8V when the pin is tied
to INTV
CC
.
PGOOD (Pin 32/Pin 4): Power Good Output. Open-drain
logic that is pulled to ground when the output voltage is
not within ±11% of the regulation point after the internal
20μs power bad mask timer expires.
SGND (Exposed Pad Pin 33, UH Package): The exposed
pad is signal ground. It must be soldered to PCB ground
for electrical contact and for rated thermal performance.