500 mA, 3.3 V Linear Regulator with Auxiliary Control

The CS5231−3 combines a three−terminal linear regulator with circuitry controlling an external PFET transistor thus managing two input supplies. The part provides a 3.3 V regulated output either from the main 5.0 V supply or a 3.3 V auxiliary that switches on when the 5.0 V supply is not present. This delivers constant, uninterrupted power to the load. The CS5231−3 meets Intel’s “Instantly Available” power requirements which follows from the “Advanced Configuration and Power Interface” (ACPI) standards developed by Intel, Microsoft and Toshiba.

Features

• Linear Regulator

− 3.3 V ± 2.0 Output Voltage

− 3.0 mA Quiescent Current @ 500 mA

− Fast Transient Response

− Current Limit Protection

− Thermal Shutdown with Hysteresis

− 450 μA Reverse Output Current

• System Power Management

− Auxiliary Supply Control

− “Glitch Free” Transition Between Two Supplies

• Internally Fused Leads in SOIC−8 Package