STEVAL-ISA052V1

STEVAL-ISA052V1 High efficiency step-down controller with embedded 2 A LDO regulator demonstration board based on the PM6675S Data brief Features ■ 4.5 V to 28 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 constant ontime loop control ■ No-RSENSE current sensing using low-side MOSFETs’ RDS(on) ■ 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 ■ RoHS compliant STEVAL-ISA052V1 applications. The LDO linear regulator can sink 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 The STEVAL-ISA052V1 demonstration board is based on the PM6675S device which consists of a single high efficiency step-down controller and an independent low drop-out (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 November 2010 Doc ID 18215 Rev 1 For further information contact your local STMicroelectronics sales office. 1/4 www.st.com 4   Doc ID 18215 Rev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igure 1.  1  6## Circuit schematic STEVAL-ISA052V1 Circuit schematic Circuit schematic           !-6 STEVAL-ISA052V1 2 Revision history Revision history Table 1. Document revision history Date Revision 12-Nov-2010 1 Changes Initial release. Doc ID 18215 Rev 1 3/4 STEVAL-ISA052V1 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. 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