Datasheet

LTC3529
5
3529fb
PIN FUNCTIONS
V
OUT
(Pin 1): Converter Output, Voltage Sense Input
and Drain of the Internal Synchronous Rectifi er MOSFET.
Driver bias is derived from V
OUT
. PCB trace length from
V
OUT
to the output fi lter capacitor(s) should be as short
and wide as possible.
SW (Pin 2): Switch Node. This node connects to one
side of the inductor. Keep PCB traces as short and wide
as possible to reduce EMI and voltage overshoot. If the
inductor current falls to zero, or SHDN is low, an internal
100Ω anti-ringing switch is connected between SW and
V
IN
to minimize EMI.
SHDN (Pin 3): Active-Low Shutdown Input. Forcing this
pin above 1V enables the converter. Forcing this pin below
0.35V disables the converter. Do not fl oat this pin.
PGND (Pin 4): High Current Ground Connection. The PCB
trace connecting this pin to ground should be as short and
as wide as possible.
FAULT (Pin 5): Open-Drain Fault Indicator Output. Pulls
low when an overcurrent condition exists for more than
22ms.
SNSGND (Pin 6): This pin must be connected to
ground.
RST (Pin 7): Logic Input to Select Automatic Restart or
Latchoff Following a Fault Shutdown.
• RST = High: Auto-reset mode. In this mode, the LTC3529
will automatically attempt to restart 22ms (typically)
after a fault shutdown.
• RST = Low: Latchoff mode. In this mode, the LTC3529
will latch off for a fault shutdown. The IC will not restart
until the SHDN pin is toggled or the supply voltage is
cycled.
V
IN
(Pin 8): Input Supply Pin.
Exposed Pad (Pin 9): Small Signal Ground. This is the
ground reference for the internal circuitry of the LTC3529
and must be connected directly to ground.