STEVAL-ISA187V1 STMicroelectronics

STEVAL-ISA187V1 38 V, 0.5 A synchronous step-down switching regulator evaluation board based on A6985F Data brief Description The STEVAL-ISA187V1 is a product evaluation board based on the ST synchronous step-down switching regulator A6985F, which can deliver up to 0.5 A and, with its 100% duty cycle ability to withstand cold crank events and wide input operating voltage range, represents the ideal choice for battery-powered automotive systems. Synchronous rectification helps achieve higher efficiency at full load as well as application compactness, while high-frequency switching (programmable up to 2 MHz) helps reduce the cost and size of power passive components while remaining outside the AM band. The device can operate in low consumption Features mode (LCM), with a quiescent current of 30 A at AECQ100 qualification V =12 V and V = 3.3 V that ensures high IN OUT 0.5 A DC output current efficiency under light load, which is a requirement 4 V to 38 V operating input voltage in typical car body applications that are active Low consumption mode or low noise mode when a car is parked. A low noise mode (LNM) Programmable ISKIP current can be selected to meet the requirements of 30 A IQ at light load (LCM VIN = 12 V and infotainment applications with forced PWM mode V =3.3 V) OUT under all load conditions. The default board 8 A IQ-SHTDWN configuration is LCM active, 2 MHz switching frequency, high I current and the switchover Adjustable f SW (250 kHz - 2 MHz) SKIP feature enabled, but all of these settings can be Output voltage adjustable from 0.85 V to VIN easily changed so the user can evaluate different Embedded output voltage supervisor application scenarios. Synchronization Adjustable soft-start time Internal current limiting Overvoltage protection Output voltage sequencing Peak current mode architecture R = 360 m R = 150 m DS(on)HS DS(on)LS Thermal shutdown RoHS compliant January 2016 DocID028932 Rev 1 1/4 www.st.com For further information contact your local STMicroelectronics sales office Schematic diagram STEVAL-ISA187V1 1 Schematic diagram Figure 1: STEVAL-ISA187V1 schematic circuit GSPG27012016DI1116 2/4 DocID028932 Rev 1 TTPP11 R1R111 10R10R RR55 NMNM TTPP22 RRSSTT SSSS//IINNHH R1R100 NMNM U1U1 AA66998855FF TTPP33 RR66 1M1M TTPP44 4 1 VVOOUUTT SSYYNNCCHH SYNCH RST J3J3 VIN FLT 15 16 VIN VBIAS LL11 44..77uuHH 2 13 VCC LX J5J5 14 RR33 NMNM L1L1AA NMNM LX 5 FSW J2J2 RR11 00 6 MLF CC77 NMNM 9 FB 3 SS/INH RR88 200k200kCC88 27p27p RR99 33k33k RR77 200k200k 8 7 DELAY COMP ++ CC1111 C3C3 R2R2 R4R4 ++ CC44 11..22pp NMNM 56k56k EP SGND PGND PGND NMNM 470nF470nF C5C5 C6C6 17 10 11 12 J1J1 68nF68nF 10nF10nF signal GND TTPP77 PGND power GND GGNNDD J4J4 TTPP88 L3L3 TTPP55 LL22 44..77uuHH VIN FLT VVIINN MMPPZZ22001122SS222211AA VVIINN EEMMII TTPP66 PGND GGNNDD CC1313AA NMNM C1C166 44..77uuFF NMNM CC1133 CC11 10u10uFF 5050VV CC22 1uF1uF C1C155 44..77uuFF C1C144 44..77uuFF CC99 10u10uFF C1C100 NMNM