STEVAL-ISA159V1 STMicroelectronics

S T E VA L - I S A 1 5 9 V 1 High efficiency synchronous step-down regulator based on the L6984 Data brief Description The STEVAL-ISA159V1 product evaluation board is based on L6984, a high-efficiency monolithic synchronous step-down regulator, capable of delivering up to 400 mA of DC current. The fixed 3.3 V output requires no external resistor divider. The L6984 is suited for home appliances, factory and building automation. The Low Consumption Mode (LCM) is designed for eco-friendly home appliances and automotive applications active during car parking, so it maximizes the efficiency at light load with controlled output voltage ripple. The Low Noise Mode (LNM) makes the switching frequency nearly constant over the load current range, serving low noise application specifications such as audio and sensors. The PGOOD open collector output can implement output voltage sequencing during the power-up phase. The synchronous rectification, designed Features for high efficiency at medium-heavy load, and the 400 mA DC output current high switching frequency capability ensure a 4.5 V to 36 V operating input voltage compact application size. Pulse-by-pulse current Synchronous rectification sensing on the low-side power element Low consumption mode or low noise mode implements effective constant current protection. 100 A IQ at light load (LCM VOUT = 3.3 V) 13 A I Q-SHTDWN Adjustable f (250 kHz - 600 kHz) SW Output voltage adjustable from 0.9 V No resistor divider required for 3.3 V VOUT VBIAS maximizes efficiency at light load 350 mA valley current limit Constant on-time control scheme PGOOD open collector Thermal shutdown RoHS compliant May 2015 DocID26977 Rev 2 1/4 www.st.com For further information contact your local STMicroelectronics sales office Schematic diagram STEVAL-ISA159V1 1 Schematic diagram Figure 1: STEVAL-ISA159V1 circuit schematic TTPP11 VVBBIIAASS R4R4 1M1M TTPP22 L6984L6984 PPGGOOOODD U1U1 TTPP33 R5R5 NMNM 7 1 VIVINN VIN PGOOD TTPP44 9 J1J1 VVOOUUTT R1R1 11MMeegg VBIAS R6R6 3 TON L1L1 68uH68uH 100k100k 6 LX TTPP55 4 ENEN EN C3C3 NMNM 8 J2J2 VCC 10 LNM R3R3 NMNM 2 FB EP GND J4J4 R7R7 R8R8 R2R2 C4C4 C5C5 11 5 NMNM NMNM 00 NMNM J3J3 470nF470nF TTPP66 GGNNDD GSPG0 11014 1140SG 2/4 DocID26977 Rev 2 C1C1 10uF10uF 50V50V C2C2 100nF100nF 50V50V C6C6 22uF22uF C7C7 NMNM