SP7648_05

SP7648 Evaluation Board Manual Easy Evaluation for the SP7648 Single or Dual Cell Alkaline to 2V to 5V Output Provides 700mA output at 3.6V output for Li-Ion Input High Efficiency: 94% µSOIC Package & SMT components for small, low profile Power Supply DESCRIPTION The SP7648 Evaluation Board is designed to help the user evaluate the performance of the SP7648 for use as a single/dual cell Alkaline or single cell Li-Ion to drive 1W LED. The output of the SP7648 is preset to +5V or can be adjusted from +2V to +5V by manipulating two external resistors. The evaluation board is a completely assembled and tested surface mount board which provides easy probe access points to all SP7648 Inputs and Outputs so that the user can quickly connect and measure electrical characteristics and waveforms. SP7648 EVALUATION BOARD SCHEMATIC Vin 3.0-4.2V C1 10uF 0805 RLIM1 OPEN SW1 1 2 D1 Shorted 1 WURTH(744042004) L1 4.7uH SP7648 VBATT FLASH NC RLIM SHDN VOUT LX PGND GND FB 10 9 8 7 6 Important: 0.1uF Ceramic Cap at Vout Pin needed for stable regulation C4 0.1uF Rc 0.33 Ohm C2 10uF 0805 Vout D2 1W LED Mode Out (TP) 2 3 4 5 C3 470pF R6 1K ON / OFF R5 1M RLIM 1K Vref Flash: Iout = 0.3V/((R2//R4+Q1 RDSon)//R1) Torch: Iout = 0.8V/R1 Flas h: FLASH = H Torch: FLASH = L J3 FLASH 1 2 3 R2 0.33 Ohm 0603 R4 open R1 4.02 Ohm 0603 R3 open Q1 MOSFET N Si1400DL SC-70 Rev 5/17/05 SP7648 Evaluation Board Manual Copyright 2005 Sipex Corporation USING THE EVALUATION BOARD 1) Powering Up the SP7648 Circuit The SP7648 Evaluation Board can be powered from inputs from +2.7V to +4.2V from a Li-Ion battery. Connect with short leads directly to the “Vbatt” and “Gnd” posts. Monitor the Output, Vref Voltage and connect the LED between the “Vout” post and the “Vref” post. 2) Using the SW1 switch and the J3 Jumper: Enabling the SP7648 Output and using the Shutdown Mode Pressing the ON/OFF button (SW1) will put the SHDN pin to VIN, which enables the SP7648. Otherwise the 1M R5 pull-down puts 0V to the SHDN pin and puts the SP7648 in the low quiescent Shutdown Mode. The SP7648 output will be in FLASH mode if the J3 Jumper is in the top or pin 1 to 2 position. If J3 is in the pin 2 to 3 position, the SP7648 will be in the Torch mode. 3) Using the Rlim Function The peak inductor current, IPEAK, is programmed externally by the RLIM resistor connected between the RLIM pin and GND. The peak inductor current is defined by: IPEAK = 1600/RLIM The SP7648 has a range for RLIM of 1.0K to 9.09K ohms. Using the IPEAK equation above gives an IPEAK range of IPEAK range = 176mA to 1600mA. The saturation current specified for the inductor needs to be greater then the peak current to avoid saturating the inductor, which would result in a loss in efficiency and could damage the inductor. The SP7648 evaluation board uses an Rlim value of 1.0K for an Ipeak = 1600mA to allow the circuit to deliver 700mA for 3.6V input. Other values could be selected using the above relationships. 2 FIGURE 1: SP7648UEB COMPONENT PLACEMENT FIGURE 2: SP7648UEB PC LAYOUT TOP SIDE FIGURE 3: SP7648UEB PC LAYOUT BOTTOM SIDE 3 TABLE1: SP7648EB LIST OF MATERIALS SP7648 Evaluation Board List of Materials Ref. Des. Qty. 1 1 2 1 1 1 1 1 Manufacturer Sipex Corp. Sipex Corp. TDK Corp TDK Corp TDK Corp Wurth Elektronik Vishay Vishay Part Number Layout Size Component Vendor Sipex 978-667-7800 www.sipex.com www.tdk.com www.tdk.com www.tdk.com www.we-online.com www.vishay.com www.vishay.com www.vishay.com www.vishay.com www.vishay.com www.vishay.com www.fairchildsemi.com www.vishay.com www.bourns.com U1 C1,2 C3 C4 L1 R1 R2,Rc R3 R4 R5 R6 RLIM1 RLIM D1 Q1 SW1 SW2 J1 J2 J3 TP 1 1 1 1 1 Vishay Vishay Vishay Fairchild Vishay Bournes 3 1 4 Sullins Sullins Mill-Max 146-6583-00 SP7648UEB Eval PC Board SP7648EU uSO-8 10-pin uSOIC Step-Up DC/DC Conv C2012X5R0J106M 0805 Ceramic 6.3V 10uF SM C1608COG1H471J 0603 Ceramic 50V 470pF SM 0.02ohm ESR C1608X7R1E104M 0603 Ceramic 25V 0.1uF SM 0.02ohm ESR 744042004 4.8x4.8x1.8mm 4.7uH, 1.7A, 0.07ohm, SM Inductor CRCW06034R02F 0603 4.02 ohm 1/10W 1% 0603 SM CRCW0603R33F 0603 0.33 ohm 1/10W 1% 0603 SM OPEN OPEN CRCW0603105J 0603 1M ohm 1/10W 5% 0603 SM CRCW0603102J 0603 1K ohm 1/10W 5% 0603 SM OPEN CRCW06031001F 0603 1K ohm 1/10W 1% 0603 SM SHORTED 30V 2.2A 0.082 Ohm N-Chan MOSFET FDN337N SOT23 Si1400DL SC-70 MOSFET 20V 1.7A 0.15Ohm@4.5V 7914J-1-E On / Off Switch N/A N/A N/A PTC36SAAN .23 x .12 3-Pin Header STC02SYAN .2x.1 Shunt 0300-115-01-4727100 .042 Dia Test Point Female Pin www.digikey.com www.digikey.com www.digikey.com www.digikey.com ORDERING INFORMATION Model Temperature Range Package Type SP7648UEB.................................. -40°C to +85°C...................SP7648 Evaluation Board SP7648EU.....................................-40°C to +85°C......................................10-pin µSOIC 4