Pin Functions - Linear Technology LT8302 Operation

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
undervoltage lockout (UVLO) threshold using a resistor
divider from V to ground. A 2.5µA current hysteresis
IN
allows the programming of V
function is used, tie this pin directly to V
INTV (Pin 2): Internal 3V Linear Regulator Output. The
CC
INTV pin is supplied from V
CC
control circuitry and gate driver. Do not overdrive the
INTV pin with any external supply, such as a third winding
CC
supply. Locally bypass this pin to ground with a minimum
1µF ceramic capacitor.
V (Pin 3): Input Supply. The V
IN
the internal circuitry and serves as a reference voltage for
the feedback circuitry connected to the R
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.
UVLO hysteresis. If neither
IN
.
IN
and powers the internal
IN
pin supplies current to
IN
pin. Locally
FB
For more information
SW (Pin 5): Drain of the Internal DMOS Power Switch.
Minimize trace area at this pin to reduce EMI and voltage
spikes.
IN
R (Pin 6): Input Pin for External Feedback Resistor.
FB
Connect a resistor from this pin to the transformer primary
SW pin. The ratio of the R
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 (Pin 7): Input Pin for External Ground Referred Ref-
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
to compensate the output diode temperature coefficient.
www.linear.com/LT8302
LT8302
resistor to the R resistor,
FB REF
REF
pin
8302fb
7