The CS5141X products are 1.5A buck regulator ICs. These devices are fixed- frequency operating at 260kHz and 520kHz. The regulators use the V control architecture to provide unmatched transient response, the best overall regulation and the simplest loop compensation for today's high- speed logic. These products accommodate input voltages from 4.5V to 40V. The CS51411 and CS51413 contain synchronization circuitry. The CS51412 and CS51414 have the option of powering the controller from an external 3.3V to 6V supply in order to improve efficiency, especially in high input voltage, light load conditions. The on-chip NPN transistor is capable of providing a minimum of 1.5A of output current, and is biased by an external "boost" capacitor to ensure saturation, thus minimizing on-chip power dissipation. Protection circuitry includes thermal shutdown, cycle-by- cycle current limiting and frequency foldback. The CS51411 and CS51413 are functionally pin-compatible with the LT1375. The CS51412 and CS51414 are functionally pin-compatible with the LT1376.