Datasheet LT8302, LT8302-3 (Analog Devices) - 7

LT8302/LT8302-3
PIN FUNCTIONS EN/UVLO (Pin 1):
Enable/Undervoltage Lockout. The
SW (Pin 5):
Drain of the Internal DMOS Power Switch. EN/UVLO pin is used to enable the LT8302/LT8302-3. Minimize trace area at this pin to reduce EMI and voltage Pull the pin below 0.3V to shut down the LT8302/LT8302- spikes. 3. This pin has an accurate 1.214V threshold and can
R
be used to program a V
FB (Pin 6):
Input Pin for External Feedback Resistor. IN undervoltage lockout (UVLO) Connect a resistor from this pin to the transformer pri- threshold using a resistor divider from VIN to ground. A mary SW pin. The ratio of the R 2.5µA current hysteresis allows the programming of V FB resistor to the RREF IN resistor, times the internal voltage reference, determines UVLO hysteresis. If neither function is used, tie this pin the output voltage (plus the effect of any non-unity trans- directly to VIN. former turns ratio). Minimize trace area at this pin.
INTVCC (Pin 2):
Internal 3V Linear Regulator Output. The
R
INTV
REF (Pin 7):
Input Pin for External Ground Referred CC pin is supplied from VIN and powers the inter- Reference Resistor. The resistor at this pin should be in nal control circuitry and gate driver. Do not overdrive the the range of 10k, but for convenience in selecting a resis- INTVCC pin with any external supply, such as a third wind- tor divider ratio, the value may range from 9.09k to 11.0k. ing supply. Locally bypass this pin to ground with a mini- mum 1µF ceramic capacitor.
TC (Pin 8):
Output Voltage Temperature Compensation. The voltage at this pin is proportional to absolute tem-
VIN (Pin 3):
Input Supply. The VIN pin supplies current to perature (PTAT) with temperature coefficient equal to the internal circuitry and serves as a reference voltage for 3.35mV/°K, i.e., equal to 1V at room temperature 25°C. the feedback circuitry connected to the RFB pin. Locally The TC pin voltage can be used to estimate the LT8302/ bypass this pin to ground with a capacitor. LT8302-3 junction temperature. Connect a resistor from
GND (Pin 4, Exposed Pad Pin 9):
Ground. The exposed this pin to the RREF pin to compensate the output diode pad provides both electrical contact to ground and good temperature coefficient. thermal contact to the printed circuit board. Solder the exposed pad directly to the ground plane. Rev. G For more information www.analog.com 7 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Application Related Parts