STEVAL-ISA052V2 Evaluation board for the PM6675AS high efficiency step-down controller with embedded 2 A LDO regulator Data Brief Features 4.5 V to 36 V input voltage range 0.6 V, 1% voltage reference 1.5 V fixed output voltage 0.6 V to 3.3 V adjustable output voltage 1.237 V 1% reference voltage available Very fast load transient response using constant on-time (COT) control loop No RSENSE current sensing using RDS(ON) of the low-side MOSFETs Negative current limit Latched OVP, UVP and thermal shutdown Fixed 3 ms soft-start Selectable pulse-skipping at light load Selectable no-audible (33 kHz) pulse-skip mode All ceramic output capacitors application supported Output voltage ripple compensation Output soft-end STEVAL-ISA052V2 and source up to 2 Apk. Two fixed current limits (1 A and 2 A) can be chosen. An active soft-end is independently performed on both the switching and the linear regulator outputs when disabled. Description This evaluation board is based on the PM6675AS device, which consists of a single high efficiency step-down controller and an independent lowdropout (LDO) linear regulator. The constant on-time (COT) architecture assures fast transient response supporting both electrolytic and ceramic output capacitors. An embedded integrator control loop compensates the DC voltage error due to the output ripple. Selectable low-consumption mode allows the highest efficiency over a wide range of load conditions. The low-noise mode sets the minimum switching frequency to 33 kHz for audio-sensitive applications. The LDO linear regulator can sink May 2008 Rev 1 For further information contact your local STMicroelectronics sales office. 1/4 www.st.com 4 PGND LGND LPG LOUT LIN VCCGND J9 J11 J8 J7 J6 J10 1 1 1 R18 100k 1 1 1 VCC 0 1 2 0 R20 10k R19 7.5k 0 C5 1u 1 2 10u C6 0 1 10u C7 NOSK SKIP JP1 2 0 R7 3R9 2 C9 100n C10 1 0 N.M. C19 N.M. C20 1 2 0 R8 12k R9 13k 1 2 3 4 5 6 25 LGND LFB NOSK SKIP LPG SGND AVCC AV THPD U1 0 C11 10u R10 0 VCC PM66 6675S VSE VSEL JP3 LILIM JP2 VCC LGATE PGND SPG SP LEN SWEN C12 100n 18 17 16 15 14 13 VCC 1 D1 BA BAT54J 2 C21 100p R3 1.2k 0 C22 100p 1 R2 18k 1 2 VCC 1 2 1 2 2 1 1 2 1 2 1 2 24 23 22 21 20 19 LOUT LIN BOOT HGATE PHAS ASE CSNS VREF VOSC VSNS VS VSEL VSE COMP LILIM 7 8 9 10 11 12 1 1 2 2 0 1 0 0 LEN-SWEN R13 100k 2 SW1 2 100k R12 1 VCC R17 100k 1 0 2 2 C17 N.M. R1 330k R4 3R3 R11 1 C13 100n 0 C14 100n 1 Q2 0 2 680p C16 0 S12NH3LL D2 1 S12NH3LL 4 4 Q1 5 6 7 8 1 2 3 5 6 7 8 1 2 3 C1 10u C18 1n R16 4R7 R14 TP1 GND_TP INT-VE VESR JP5 0 C2 10u 7.5k 1 2 C15 1 6.8n 2 R15 6.8k MLC1240-901ML L1 0.9u 0 2x UMK325BJ106KM-T 1 2 J5 STPS1L30M 1 2 VCC 2 4 6 1 3 5 1 2 1 2 R6 0 220u C3 2x 4TPE220MF 1 2 2 4 3 1 2 2 4 6 1 3 5 1 2 1 2 1 2/4 2 22 220u C4 J2 J1 1 1 J4 J3 PS1L30A STPS D3 1 1 SPG SP PGND VOUT VIN Figure 1. 1 2 1 1 2 Circuit schematic STEVAL-ISA052V2 Circuit schematic Schematic diagram STEVAL-ISA052V2 2 Revision history Revision history Table 1. Document revision history Date Revision 05-May-2008 1 Changes Initial release. 3/4 STEVAL-ISA052V2 Please Read Carefully: Information in this document is provided solely in connection with ST products. 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