LTM8031 Typical perForMance characTerisTics TA = 25°C, unless otherwise noted.Radiated EmissionsRadiated Emissions 90 90 VIN = 36V VIN = 36V 80 VOUT = 10V AT 1A 80 VOUT = 2.5V AT 1A 70 70 60 60 50 50 40 EN55022 EN55022 CLASS B 40 CLASS B 30 LIMIT 30 LIMIT 20 20 EMISSIONS LEVEL (dBµV/m) 10 EMISSIONS LEVEL (dBµV/m) 10 0 0 –10 –10 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (MHz) FREQUENCY (MHz) 8031 G19 8031 G20 pin FuncTions VIN (Bank 3): The VIN pin supplies current to the LTM8031’s BIAS (Pin H4): The BIAS pin connects to the internal power internal regulator and to the internal power switch. This bus. Connect to a power source greater than 2.8V. If the pin must be locally bypassed with an external, low ESR output is greater than 2.8V, connect this pin to AUX. If the capacitor of at least 1µF . output voltage is less, connect this to a voltage source FIN (K3, L3): Filtered Input. This is the node after the input between 2.8V and 25V. Also, make sure that BIAS + VIN EMI filter. Use this only if there is a need to modify the is less than 56V. behavior of the integrated EMI filter or if VIN rises or falls RUN/SS (Pin L5): Pull RUN/SS pin to less than 0.2V to rapidly; otherwise, leave these pins unconnected. See the shut down the LTM8031. Tie to 2.5V or more for normal Applications Information section for more details. operation. If the shutdown feature is not used, tie this pin GND (Bank 2): Tie these GND pins to a local ground plane to the VIN pin. RUN/SS also provides a soft-start function; below the LTM8031 and the circuit components. Return see the Applications Information section. the feedback divider (RADJ) to this net. RT (Pin G7): The RT pin is used to program the switching V frequency of the LTM8031 by connecting a resistor from OUT (Bank 1): Power Output Pins. Apply the output filter capacitor and the output load between these pins and this pin to ground. The Applications Information section of GND pins. the data sheet includes a table to determine the resistance value based on the desired switching frequency. Minimize AUX (Pin H5): Low Current Voltage Source for BIAS. In capacitance at this pin. many designs, the BIAS pin is simply connected to VOUT . The AUX pin is internally connected to V SHARE (Pin H7): Tie this to the SHARE pin of another OUT and is placed adjacent to the BIAS pin to ease printed circuit board rout- LTM8031 when paralleling the outputs. ing. Although this pin is internally connected to VOUT , donot connect this pin to the load. If this pin is not tied to BIAS, leave it floating. 8031fb 6 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical application Related Parts