STEVAL-ISA152V1 STMicroelectronics

STEVAL-ISA152V1 3.3 V/3 A high efficiency step down DC-DC converter (V = 4.5 to 60 V) based on the L7987 IN Data brief Description The STEVAL-ISA152V1 product evaluation board is a step-down switching power supply based on the L7987 regulator in an HTSSOP16 package. The output voltage can be set starting from 0.8 V. Low drop-out operation, with almost 100% duty cycle, can be achieved. The L7987 is a 61 V, 3 A step-down asynchronous switching regulator with embedded power MOSFET caable of delivering up to 3 A of current, depending on the application conditions. The embedded switch-over feature on the VBIAS pin and the light load management (pulse skipping) are intended to maximize power Features conversion efficiency across the entire load range. 3.3 V output voltage 3 A DC output current The soft-start, current limit threshold and the 4.5 V to 60 V input voltage switching frequency are adjustable for application optimization. 500 kHz switching frequency 3.5 ms programmed soft-start The device includes an internal 250 kHz oscillator VBIAS switch-over for improved efficiency at that can be externally adjusted up to 1.5 MHz light load two L7987 regulators can be synchronized in a 180 out of phase synchronization available 180 out-of-phase configuration for reduced total Open drain PGOOD available input RMS current. Auto recovery overcurrent and thermal protection RoHS compliant May 2014 DocID025489 Rev 1 1/4 www.st.com For further information contact your local STMicroelectronics sales office Schematic diagram STEVAL-ISA152V1 1 Schematic diagram Figure 1: Schematic diagram GSPG08112013DI1045 2/4 DocID025489 Rev 1 R1 NM TP1 PGOOD U1 TP2 R2 100k TP4 7 12 VOUT SYNCH SYNCH PGOOD TP3 J2 2 1 VIN VIN VBIAS 3 0 R3 VIN 15 R4 BOOT C7 0 J1 4 100nF J3 VCC L7987 TP5 5 13 EN L1 10uH EN LX 14 LX 6 R5 68 C8 10nF SS 9 FB 10 FSW R6 620 C9 33nF R7 6.8k 11 8 ILIM TP GND COMP C11 1nF 17 16 D1 R8 R9 STPS3L60 47k NM R10 R11 N.M. 2.2k signal GND power GND TP6 TP7 GND GND C1 4.7uF 100V C2 4.7uF 100V C3 1uF 100V C4 1uF 100V C10 22nF C5 47uF C6 NM