LT8302
7
8302fb
For more information
www.linear.com/LT8302
pin FuncTions
EN/UVLO (Pin 1):
Enable/Undervoltage Lockout. The
EN/UVLO pin is used to enable the LT8302. Pull the pin
below 0.3V to shut down the LT8302. This pin has an ac-
curate 1.214V 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
.
INTV
CC
(Pin 2):
Internal 3V Linear Regulator Output. The
INTV
CC
pin is supplied from V
IN
and powers the internal
control circuitry and gate driver. Do not overdrive the
INTV
CC
pin with any external supply, such as a third winding
supply. Locally bypass this pin to ground with a minimum
1µF ceramic capacitor.
V
IN
(Pin 3):
Input Supply. The V
IN
pin supplies current to
the 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.
GND (Pin 4, Exposed Pad Pin 9):
Ground. The exposed
pad provides both electrical contact to ground and good
thermal contact to the printed circuit board. Solder the
exposed pad directly to the ground plane.
SW (Pin 5):
Drain of the Internal DMOS Power Switch.
Minimize trace area at this pin to reduce EMI and voltage
spikes.
R
FB
(Pin 6):
Input Pin for External Feedback Resistor.
Connect a resistor from this pin to the transformer primary
SW pin. The ratio of the R
FB
resistor to the R
REF
resistor,
times the internal voltage reference, determines the output
voltage (plus the effect of any non-unity transformer turns
ratio). Minimize trace area at this pin.
R
REF
(Pin 7):
Input Pin for External Ground Referred Ref-
erence Resistor. The resistor at this pin should be in the
range of 10k, but for convenience in selecting a resistor
divider ratio, the value may range from 9.09k to 11.0k.
TC (Pin 8):
Output Voltage Temperature Compensation. The
voltage at this pin is proportional to absolute temperature
(PTAT) with temperature coefficient equal to 3.35mV/°K,
i.e., equal to 1V at room temperature 25°C. The TC pin
voltage can be used to estimate the LT8302 junction tem-
perature. Connect a resistor from this pin to the R
REF
pin
to compensate the output diode temperature coefficient.
