SP6659EB Evaluation Board Manual Synchronous Buck regulator with up to 94% efficiency 1.5MHz Constant frequency operation 600mA Output Current 2.5V-5.5V Input Voltage range, 0.6V reference allow low output voltage No Schottky diode required Current mode operation Over-temperature protected Low profile SOT23-5 Package & Ceramic Capacitors for small, low profile Power Supply Ideal for PDAs, Digital Cameras, Wireless Modems, Cellular Telephones DESCRIPTION The SP6659 Evaluation Board is designed to help the user evaluate the performance of the SP6659 for use as a single Li-Ion battery Step-Down DC-DC Converter. The SP6659 operates from 2.5V to 5.5V input, with the highest efficiency in the range 3.0V to 4.2V where the Li-Ion battery has the most energy. The SP6659EB evaluation board is a complete power supply circuit to provide ease of evaluation for the DC/DC Converter performance. FIGURE 1. SP6659 1.8V OUTPUT EVALUATION BOARD SCHEMATIC U1 Vin=2.5-5.5V 1 2 3 J1 CIN 4.7uF 4 1 2 SP6659 VIN SW 3 RUN VFB GND 5 L1 2.2 uH R1 200K Vout=1.8V CF 100pF VFB=0.6V R2 100K Rev 08/29/05 SP6659 Evaluation Board Manual Copyright Sipex Corporation COUT 10uF USING THE EVALUATION BOARD 1) Powering up the SP6659 Circuit The SP6659 Evaluation Board can be powered from a single Li-Ion battery or a +2.5 to +5.5V power supply. Connect with short leads directly to the “Vin” and “Gnd” posts. Note the SP6659 will remain in “shutdown” until the “RUN” Jumper J1 is applied to the Vin or position 1 to 2. 2) VOUT PROGRAMMING The SP6659 has a dynamically programmable output voltage using 2 feedback resistors to control the output voltage: Vout R1 = − 1 • R 2 0 .6 OR R1 Vout = 0.61 + R2 Table 1. SP6659EB BILL OF MATERIALS Ref.Des. Qty Manufacturer Part Number Size Component Vendor Eval bd 1 Sipex Corp 146-6595-00 1"x1.5" SP6659 Eval board Sipex 408-937-7500 U1 1 Sipex Corp SP6659 SOT23-5 5 pins SOT23 DC/DC Conv Sipex 408-937-7500 Cin 1 Murata GRM188R60J475KE19D 0603 Ceramic 4.7uF 6.3V X5R murata.com Cout 1 Murata GRM21BR60J106KE19 0805 Ceramic 10uF 6.3V X5R murata.com Cf 1 Murata GRM1885C1H101JA01B 603 Ceramic 100pF 50V COG murata.com L1 1 Murata LQH32CN2R2M53K 1210 2.2uH 790mA 97mΩ 1.5mm thick murata.com R1 1 Vishay CRCW06032003F 0603 200KΩ, 1/10W, 1% vishay.com R2 1 Vishay CRCW06031003F 0603 100KΩ, 1/10W, 1% vishay.com J1 TP 1 Sullins PTC36SAAN .23x.12 3 Pin Header 800-digi-key 1 Sullins STC02SYAN .2x.1 Shunt 800-digi-key 3 Mill-Max 0300-115-01-4727100 .042" dia Test Point Female Pin 800-digi-key Table 2. SP6659 PIN ASSIGNMENT Pin Name Pin Description Pin # RUN Power down control pin. Forcing this pin above 1.5V enables the device. Forcing this pin below 0.3V shuts down the device. 1 GND Ground pin 2 SW Switching node 3 Vin Power supply pin 4 VFB Feedback. Receives the feedback voltage from an external resistive divider across output. 5 2 EVALUATION BOARD LAYOUT FIGURE 2: SP6659EB COMPONENT PLACEMENT FIGURE 3: SP6659EB PC LAYOUT TOP SIDE FIGURE 4: SP6659EB PC LAYOUT BOTTOM SIDE 3