Like any low-dropout regulator, the external capacitors used with the RT9193 must be carefully selected for regulator stability and_performance. Using a capacitorwhose value is > 1μF on the RT9193 input and_the amountof capacitance can be increased without limit. The inputcapacitor must be located a distance of not more than0.5 inch from the input pin of the IC and_returned to aclean analog ground. Any good quality ceramic ortantalum can be used for this capacitor. The capacitor with larger value and_lower ESR (equivalent seriesresistance) provides better PSRR and_line-transientresponse. The output capacitor must meet both requirements for minimum amount of capacitance and ESR in all LDOs application. The RT9193 is designedspecifically to work with low ESR ceramic output capacitor in space-saving and_performance consideration. Usinga ceramic capacitor whose value is at least 1μF with ESRis > 25mΩ on the RT9193 output ensures stability. TheRT9193 still works well with output capacitor of othe rtypes due to the wide stable ESR range. Figure 1 shows the curves of allowable ESR range as a function of loadcurrent for various output capacitor values. Outputcapacitor of larger capacitance can reduce noise and improve load transient response, stability, and_PSRR. The output capacitor should be located not more than 0.5inch from the VOUT pin of the RT9193 and_returned to aclean analog ground.Figure 1Bypass Capacitor and_Low NoiseConnecting a 22nF between the BP pin and_GND pin significantly reduces noise on the regulator output, it iscritical that the capacitor connection between the BP pinand_GND pin be direct and_PCB traces should be as short as possible. There is a relationship between the bypasscapacitor value and_the LDO regulator turn on time. DCleakage on this pin can affect the LDO regulator outputnoise and_voltage regulation performance. Enable FunctionThe RT9193 features an LDO regulator enable/disablefunction. To assure the LDO regulator will switch on, theEN turn on control l evel must be greater than 1.2 volts. The LDO regulator will go into the shutdown mode when the voltage on the EN pin falls below 0.4 volts. For to protect the system, the RT9193 have a quick-discharge function. If the enable function is not needed in a specific application, it may be tied to VIN to keep the LDO regulatorin a continuously on state. Thermal Considerations Thermal protection limits power dissipation in RT9193. When the operation junction temperature exceeds 165°C, the OTP circuit starts the thermal shutdown function turn the pass element off. The pass element turn on again after the junction temperature cools by 30°C. For continue operation, do not exceed absolute maximum operation junction temperature 125°C. The powerdissipation definition in device is :PD = (VIN?VOUT) x IOUT + VIN x IQThe maximum power dissipation depends on the thermalresistance of IC package, PCB layout, the rate ofsurroundings airflow and_temperature difference between junction to ambient. The maximum power diss sipation can be calculated by the following formula : PD(MAX) = ( TJ(MAX)? TA ) /θJAWhere TJ(MAX) is the maximum operation junctiontemperature 125°C, TA is the ambient temperature and theθJA is the junction to ambient thermal resistanc