RT9027BGS Richtek

RT9027A/B Linear Fan Driver General Description Features zz z zz V Follows 1.6 Times of V OUT SET The RT9027A/B is a high performance positive voltage zz z zz 150mV Dropout 0.5A regulator designed for very low dropout voltage up to 0.5 zz z zz Over Current and Over Temperature Protection Amps. The V voltage must be larger than 1V to guarantee SET zz z zz FON Pin Turns V Fully On OUT that V is 1.6 times of V . When V is less than 1V, OUT SET SET zz z zz RoHS Compliant and 100% Lead (Pb)-Free the IC will be shutdown. The FON pin turns V to fully- OUT on when FON is given low. For RT9027B (EN version), Applications FON pin is equivalent to EN pin. The RT9027A/B provides excellent regulation over variations in line, load and z Notebook Computer Fan Driver temperature. The RT9027A/B is available in the SOP-8 z Battery Powered System package. z Motherboard z Peripheral Card Ordering Information RT9027 Pin Configurations Package Type (TOP VIEW) S : SOP-8 Lead Plating System FON GND 8 P : Pb Free VIN 2 7 GND G : Green (Halogen Free and Pb Free) VOUT 3 6 GND 4 5 VSET GND A : FON Function B : EN Function RT9027A Note : EN 8 GND Richtek products are : 2 VIN 7 GND RoHS compliant and compatible with the current require- VOUT 3 6 GND ments of IPC/JEDEC J-STD-020. VSET 4 5 GND Suitable for use in SnPb or Pb-free soldering processes. RT9027B SOP-8 Typical Application Circuit 3 2 V VIN IN V VOUT OUT C C IN OUT RT9027A/B 2.2uF 2.2uF 4 V VSET SET 5 to 8 GND 1 FON/EN FON/EN DS9027A/B-02 April 2011 www.richtek.com 1RT9027A/B Functional Pin Description Pin No. Pin Name Pin Function Internal pulled high. For RT9027A, the IC will be fully turned on when this pins voltage is FON below 0.4V. 1 Internal pulled high. For RT9027B, the IC will be shutdown when this pins voltage is EN below 0.4V. 2 VIN Input Voltage Pin. 3 VOUT Output Voltage Pin. This pin is used for output voltage setting. It is necessary to make this pin higher than 1V 4 VSET to guarantee V to be 1.6 times of VSET. The IC will be shutdown when this pin voltage OUT is below 1V. 5 to 8 GND Ground. Function Block Diagram VIN BIAS+Thermal V POR IN Shutdown V POR SET VSET (Enable) OCP - EA + VOUT Logic FON/EN 0.6 1 GND www.richtek.com DS9027A/B-02 April 2011 2