L6984ATR STMicroelectronics

L6984 36 V, 400 mA synchronous step-down switching regulator Datasheet - production data Application Battery powered applications (LCM) Sensors (LNM) VFDFPN10 4 x 4 x 1.0 mm E- metering Description VDFPN10 3 x 3 x 1.0 mm The L6984 is a step-down monolithic switching regulator able to deliver up to 400 mA DC. The output voltage adjustability ranges from 0.9 V. The Features fixed 3.3 V V requires no external resistor OUT divider. The Low Consumption Mode (LCM) is 400 mA DC output current designed for applications active during car 4.5 V to 36 V operating input voltage parking, so it maximizes the efficiency at light load Synchronous rectification with controlled output voltage ripple. The Low Noise Mode (LNM) makes the switching Low consumption mode or low noise mode frequency almost constant over the load current 75 A I at light load (LCM V = 3.3 V) Q OUT range, serving low noise application specification 13 A I like car audio/sensors. The PGOOD open Q-SHTDWN collector output can implement output voltage Adjustable f (250 kHz - 600 kHz) SW sequencing during the power-up phase. The Output voltage adjustable from 0.9 V synchronous rectification, designed for high No resistor divider required for 3.3 V V efficiency at medium - heavy load, and the high OUT switching frequency capability make the size of V maximizes efficiency at light load BIAS the application compact. Pulse-by-pulse current 350 mA valley current limit sensing on low-side power element implements Constant on-time control scheme an effective constant current protection. PGOOD open collector Thermal shutdown Figure 1. Application schematic 8 / 73 73 73 73 3*22 3*22 9,19,1 9,1 3*22 5 5 5 5 0HJ 0HJ 9%, 6 N N 1 / / X+ X+ 73 73 92879287 / 73 73 5 5 0 0 (1(1 (1 9&& /10 )% (3 *1 & & Q) Q) 73 73 *1 *1 0 9 May 2018 DocID025378 Rev 6 1/47 This is information on a product in full production. www.st.com & & X) X) 9 9 & & Q) Q) 9 9 & & X X 72Contents L6984 Contents 1 Pin settings 4 1.1 Pin connection 4 1.2 Pin description 4 1.3 Maximum ratings 5 1.4 Thermal data . 5 1.5 ESD protection 6 2 Electrical characteristics . 7 3 Device description . 10 3.1 Output voltage adjustment 12 3.1.1 Maximum output voltage 12 3.1.2 Leading network 13 3.2 Control loop . 15 3.3 Optional virtual ESR network 19 Output voltage accuracy and optimized resistor divider . 22 3.4 Soft-start 25 3.5 Light load operation . 25 3.5.1 Low noise mode (LNM) . 25 3.5.2 Low consumption mode (LCM) . 26 3.6 Switchover feature 28 3.6.1 LCM 28 3.6.2 LNM 29 3.7 Overcurrent protection . 29 3.8 PGOOD 31 3.9 Overvoltage protection . 31 3.10 Thermal shutdown 32 4 Design of the power components . 33 4.1 Input capacitor selection 33 4.2 Inductor selection . 34 4.3 Output capacitor selection 35 2/47 DocID025378 Rev 6