The CS2001 is a smart power supply ASIC utilized in automotive airbag systems. It contains a currentmode switching regulator with a 1.2 A onchip switch and a 5.0 V, 100 mA linear regulator. The linear output capacitor must be 3.3 F or greater with an ESR in the range of 100 m to 1.0 . If the ESR of the cap is less than 100 m, a series resistor must be used. The switcher can be configured in either a boost or flyback topology. The boost topology produces energy reserve voltage VER which is externally adjustable (25 V maximum) through the resistor divider connected to the VFB pin. In the event of fault conditions that produce VFB either open or shorted, the switcher is shut down.