STEVAL-ISA052V2 STMicroelectronics

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 R of DS(ON) the low-side MOSFETs Negative current limit STEVAL-ISA052V2 Latched OVP, UVP and thermal shutdown Fixed 3 ms soft-start and source up to 2 Apk. Two fixed current limits (1 A and 2 A) can be chosen. Selectable pulse-skipping at light load An active soft-end is independently performed on Selectable no-audible (33 kHz) pulse-skip both the switching and the linear regulator outputs mode when disabled. All ceramic output capacitors application supported Output voltage ripple compensation Output soft-end Description This evaluation board is based on the PM6675AS device, which consists of a single high efficiency step-down controller and an independent low- dropout (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 1/4 For further information contact your local STMicroelectronics sales office. www.st.com 4Circuit schematic STEVAL-ISA052V2 1 Circuit schematic Figure 1. Schematic diagram 2/4 J1 VCC 2x UMK325BJ106KM-T J5 VCC 1 2 1 VIN VCC 1 C11 R1 330k 10u R2 C14 C5 R7 D1 18k 100n C1 C2 1u 10u 3R9 BABAT54J 10u J10 VCCGND 1 R10 Q1 R6 J6 0 0 0 0 0 0 C12 0 0 100n LIN 1 R4 3R3 1 2 4 S12NH3LL J7 LOUT 1 MLC1240-901ML 1 2 L1 0.9u J2 C6 C7 C19 C20 2x 4TPE220MF R19 R3 1.2k 1 2 1 VOUT 7.5k 10u 10u N.M. N.M. U1 1 2 C13 VCC 100n C3 C4 25 Q2 THPD R14 7.5k R15 6.8k D3 0 0 0 VCC 1 18 R17 0 LGND VCC STPSPS1L30A R20 2 17 4 220u 22220u LFB LGATE 10k 3 16 NOSSKKIP PGND R18 4 15 R16 LPG SPSPG 100k 5 PM666675S 14 D2 4R7 SGND LEN 6 13 S12NH3LL 1 2 AVAVCC SWEN J8 0 VCC LPG 1 C10 R11 100k C18 C15 6.8n 1 2 1n 100n C21 R12 100k 2 1 100p 1 2 C22 JP1 C9 100p JP2 SW1 TP1 R9 JP3 GND TP 13k R13 100k J3 0 NOSKSKIP LILIM LEN-SWEN 1 PGND J11 VSEVSEL LGND 1 R8 12k 0 J4 J9 1 SPSPG 0 0 PGND 1 JP5 0 1 2 C16 680p INT-VVEESR C17 0 N.M. 0 2 1 2 1 1 2 3 4 5 6 2 1 2 1 2 1 2 1 2 1 2 1 7 24 VREF LOUT 8 23 VOSC LIN 9 22 VVSSNS BOOT 10 21 VVSESEL HGATE 11 20 COMP PHAASSE 12 19 LILIM CSNS 2 1 1 2 1 2 3 4 5 6 2 1 2 1 2 1 1 4 2 3 2 1 2 1 2 1 1 5 1 5 2 6 2 6 3 7 3 7 8 8 2 1 STPS1L30M 2 1 2 1 2 1 2 1 2 1 2 1