BL9198-28BAPURN

BL9198 300mA Ultra tra-low Noise, Ultra tra-Fast CMOS LDO LDO Regul Regula ulator Hand-Held Instruments PCMCIA Cards MP3/MP4/MP5 Players Portable Information Appliances FEATURES Ultra-low Noise for RF Application Ultra-Fast Response in Line/Load Transient 1.2V, IOUT=0mA IOUT=200mA, VOUT=2.8V IOUT=300mA, VOUT=2.8V VIN=3.6V to 5.5V IOUT=1mA 1mA 25mΩ on the BL9198 output ensures stability. The BL9198 still works well with output capacitor of other types due to the wide stable ESR range. Output capacitor of larger capacitance can reduce noise and improve load transient response, stability, and PSRR. The output capacitor should be located not more than 0.5 inch from the VOUT pin of the BL9198 and returned to a clean analog ground. Enable Function The BL9198 features an LDO regulator enable/disable function. To assure the LDO regulator will switch on; the EN turn on control level must be greater than 1.2 volts. The LDO regulator will go into the shut- down mode when the voltage on the EN pin falls below 0.4 volts. For to protect the system, the BL9198 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 regulator in a continuously on state. Thermal Considerations Thermal protection limits power dissipation in BL9198. When the operation junction temperature exceeds 165°C, the OTP circuit starts the thermal shutdown function turn the pass element off. The pass element turns on again after the junction temperature cools by 30°C. For continue operation, do not exceed absolute maximum operation junction temperature 125°C. The power dissipation definition in device is: PD(MAX) = ( TJ(MAX) − TA ) /θJA Where TJ(MAX) is the maximum operation junction temperature 125°C, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. For recommended operating conditions specification of BL9198, where TJ(MAX) is the maximum junction temperature of the die (125°C) and TA is the maximum ambient temperature. The junction to ambient thermal resistance (θJA is layout dependent) for SOT-23-5 package is 250°C/W, SC-705 package is 333°C/W, on standard JEDEC 51-3 thermal test board. The maximum power dissipation at TA= 25°C can be calculated by following formula: PD(MAX) = (125°C−25°C)/333 = 300mW (SC-70-5) 3 BL9198 Rev 2.1 3/2017 www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2011 Belling All Rights Reserved 8 BL9198 300mA Ultra tra-low Noise, Ultra tra-Fast CMOS LDO LDO Regul Regula ulator PD(MAX) = (125°C−25°C)/250 = 400mW (SOT-23-5) The maximum power dissipation depends on operating ambient temperature for fixed TJ(MAX) and thermal resistance θJA. It is also useful to calculate the junction of temperature of the BL9198 under a set of specific conditions. In this example let the Input voltage VIN=3.3V, the output current Io=300mA and the case temperature TA=40°C measured by a thermal couple during operation. The power dissipation for the VOUT=2.8V version of the BL9198 can be calculated as: PD = (3.3V−2.8V) ×300mA+3.6V×100uA =150mW And the junction temperature, TJ, can be calculated as follows: TJ=TA+PD×θJA=40°C+0.15W×250°C/W =40°C+37.5°C=77.5°C