LTC3803 datasheet(6/24 Pages) LINER

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LT8300

8300f

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 VIN

undervoltage lockout (UVLO) threshold using a resistor

divider from VIN to ground. A 2.5µA current hysteresis

allows the programming of VINUVLOhysteresis.Ifneither

function is used, tie this pin directly to VIN.

GND (Pin 2): Ground. Tie this pin directly to local ground

plane.

RFB (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 RFB 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.

VIN (Pin 5): Input Supply. The VIN pin supplies current

to internal circuitry and serves as a reference voltage for

the feedback circuitry connected to the RFB pin. Locally

bypass this pin to ground with a capacitor.

LTC3803 Datasheet(PDF) 6 Page - Linear Technology