LT8300
pin FuncTions
EN/UVLO (Pin 1):
Enable/Undervoltage Lockout. The
EN/UVLO pin is used to enable the LT8300. Pull the pin
below 0.3V to shut down the LT8300. This pin has an ac-
curate 1.223V threshold and can be used to program a V
IN
undervoltage lockout (UVLO) threshold using a resistor
divider from V
IN
to ground. A 2.5µA current hysteresis
allows the programming of V
IN
UVLO hysteresis. If neither
function is used, tie this pin directly to V
IN
.
GND (Pin 2):
Ground. Tie this pin directly to local ground
plane.
R
FB
(Pin 3):
Input Pin for External Feedback Resistor.
Connect a resistor from this pin to the transformer pri-
mary SW pin. The ratio of the R
FB
resistor to the internal
trimmed 12.23k resistor, times the internal bandgap
reference, determines the output voltage (plus the effect
of any non-unity transformer turns ratio). Minimize trace
area at this pin.
SW (Pin 4):
Drain of the 150V Internal DMOS Power
Switch. Minimize trace area at this pin to reduce EMI and
voltage spikes.
V
IN
(Pin 5):
Input Supply. The V
IN
pin supplies current
to internal circuitry and serves as a reference voltage for
the feedback circuitry connected to the R
FB
pin. Locally
bypass this pin to ground with a capacitor.
8300f
6
LINER [ LINEAR TECHNOLOGY ]
