NJW4171 2.4MHz, 2.5A MOSFET Switching Regulator IC for Buck Converter FEATURES GENERAL DESCRIPTION High Oscillating Frequency 100kHz to 2.4MHz The NJW4171 is a high speed oscillating frequency High Efficiency at Light Loads A ver. buck converter with 40V/2.5A MOSFET. It has two lineup: Low Iq at Sleep Mode Iq=120A typ. A ver. the A version has PWM/PFM mode to ensure high Current Mode Control efficiency at light load, the B version is forced PWM External Clock Synchronization mode. Wide Operating Voltage Range 3.4V to 40V Operating voltage range is wide input range from 3.4V Switching Current 3.6A min. to 40V, it can correspond to supply voltage drop such as PWM Control cold crank. Moreover, 100% maximum duty cycle Maximum Duty Cycle 100% contribute to maintain stable output voltage even if supply External Compensation Circuit voltage drops. Correspond to Ceramic Capacitor (MLCC) The NJW4171 has wide switching oscillating Soft Start Function 2ms typ. frequency range, 100kHz to 2.4MHz and internal external UVLO (Under Voltage Lockout) clock synchronization function. Therefore the NJW4171 Over Current Protection (Hiccup type) can avoid interference with the AM radio frequency. Thermal Shutdown Protection Internal protection functions: UVLO, an over current Power Good Function protection and a thermal shutdown circuit can protect Standby Function circuit when abnormal condition. Package Outline HSOP8-M1 The NJW4171 has wide coverage in consumer electronics and industrial application, because of features that are wide input range, wide switching oscillating APPLICATION frequency range and 100% maximum duty cycle. Consumer Electronics Industrial Equipment PRODUCT CLASSOFOCATION High voltage to logic and microprocessor power supplies FUNCTION NAME Ver. NJW4171GM1-A A With light load mode NJW4171GM1-B B Without light load mode TYPICAL APPLICATION APPLICATION CHARACTERISTICS Efficiency vs. Output Current (A ver., V =5V, f =500kHz) OUT OSC V IN 100 + EN/SYNC EN/SYNC V High: ON V =8V 90 Low: OFF C C IN IN2 IN1 (Standby) V =12V IN 80 NJW4171 L V OUT 70 Power Good PG SW V =16V IN SBD 60 C C OUT FB R2 RT 50 R T FB 40 GND COMP R1 30 R C 20 C C 10 0 0.1 1 10 100 1000 10000 Output Current I mA OUT Ver.1.6 - 1 - www.njr.com Efficiency % NJW4171 BLOCK DIAGRAM + V Slope Current COMP. Sense UVLO OCP EN/SYNC Enable High: ON (Standby) Low: OFF(Standby) SYNC OSC S Q Buffer R SW RT TSD COMP PWM FB Error AMP Soft Start Vref 0.8V GND A ver. only Light Load Mode PG Power Good OVP Control Logic PIN CONFIGURATION PIN NO. SYMBOL DESCRIPTION + 1 1 SW Switch output SW 8 V 2 GND Ground GND 2 7 EN/SYNC 3 COMP Error Amplifier output COMP 3 6 PG 4 FB Feedback input 5 RT Oscillating frequency setting FB 4 5 RT 6 PG Power Good output Enable control and Exposed PAD on 7 EN/SYNC backside connect to GND external clock synchronization + 8 V Power supply Note) Exposed Pad on backside should be connected to ground and soldered to PCB. Ver.1.6 - 2 - www.njr.com