The LM284xSIMPLE SWITCHER devices are PWM DC/DC buck (step-down)regulators. With an input range from 4.5 V to 42 V, they are suitable for a wide range ofapplications, such as power conditioning from unregulated sources. They feature a lowRDSON (0.9 typical) internal switch for maximum efficiency(85% typical). Operating frequency is fixed at 550 kHz (X option) and1.25 MHz (Y option), allowing the use of small external components while still beingable to have low output voltage ripple. Soft start can be implemented using the shutdown(SHDN) pin with an external RC circuit allowing the user to tailor thesoft-start time to a specific application.
The LM2840 isoptimized for up to 100 mA, the LM2841XBMKX/NOPB for up to 300 mA, and the LM2842 for up to 600mAload currents. They all have a 0.765-V nominal feedback voltage.
Additional features include: thermal shutdown, VIN undervoltagelockout, and gate-drive undervoltage lockout. The LM284x are available in a low-profile SOT-6L package.
Feature
Input voltage 4.5 V to 42 V
Output current options of 100 mA, 300 mA, and 600 mA
Feedback pin voltage of 0.765 V
550-kHz (X) or 1.25-MHz (Y) switching frequency
Low shutdown IQ: 16-μA typical
Short-circuit protected
Internally compensated
Soft-start circuitry
Small overall solution size (SOT-6L package)
Create a custom design using the LM2840 (or LM2841/42) with the WEBENCH Power Designer
Catalogue
FPGA / CPLD
Memory
MOS 
MCU 
DSP
OCEP
Secondary 
Other 
