CS5231-3

CS5231-3 CS5231-3 500mA, 3.3V Linear Regulator with Auxiliary Control Description The CS5231-3 combines a threeterminal linear regulator with circuitry to control an external PFET transistor with the intent of managing two input supplies. A 5V supply powers the regulator while an auxiliary 3.3V supply is controlled by the IC. The design has been optimized to provide a “glitch-free” transition between the two supplies. The CS5231-3 linear regulator provides a fixed 3.3V output @ 500mA with an overall accuracy of ± 2%. The NPN-PNP composite pass transistor provides a low dropout voltage and requires less supply current than PNP designs. Full protection including current limit and thermal shutdown is provided. Also designed for low reverse current, the IC prevents excessive current from flowing from the output to ground if the regulator input voltage is lower than the output voltage. The CS5231-3 also controls an auxiliary supply that can provide power to the regulator output when input voltage for the regulator is not available. The AuxDrv auxiliary output is normally pulled up to the regulator input voltage and drives low whenever the input voltage drops below 4.4V (nominal). It is typically used to control a PFET switch that connects a 3.3V auxiliary supply to the regulator output. The CS5231-3 is available in a 5-lead D2PAK (TO-263) package. Applications include Network Interface Cards (NICs), modem cards and power supplies with multiple input sources. Features Linear Reg...