SP6648EU

SP6648 Evaluation Board Manual Easy Evaluation for the SP6648 Single or Dual Cell Alkaline to 2V to 5V Output Provides 300mA output at 3.3V output for 2.0V Input High Efficiency: 94% µSOIC Package & SMT components for small, low profile Power Supply DESCRIPTION The SP6648 Evaluation Board is designed to help the user evaluate the performance of the SP6648 for use as a single or dual cell input to +3.3V output DC-DC Converter. The output of the SP6648 is preset to +3.3V or can be adjusted from +2V to +5.5V 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 SP6648 Inputs and Outputs so that the user can quickly connect and measure electrical characteristics and waveforms. SP6648 EVALUATION BOARD SCHEMATIC VBATT C1 + 1 L1 10uH 3.3Vout VBATT LBI LBON RLIM SHDN VOUT 10 47uF LBI LBON SHDN RLIM 1.87K 2 3 4 5 SP6648 LX 9 PGND GND FB 8 7 6 C4 1uF R1 205K C3 47pF + C2 47uF R2 124K USING THE EVALUATION BOARD 1) Powering Up the SP6648 Circuit The SP6648 Evaluation Board can be powered from inputs from a +0.95V to +3.3V from 1 or 2 alkaline cells. Connect with short leads directly to the “Vbatt” and “Gnd” posts. Monitor the Output Voltage and connect the Load between the “Vout” post and the 2nd “GND” post. 2) Using the J1 Jumper: Enabling the SP6648 Output and using the Shutdown Mode The SP6648 output will be Enabled if the J1 Jumper is in the top or pin 1 to 2 position. If J1 is in the pin 2 to 3 position, the Shutdown pin is brought to GND, which puts the SP6648 in the low quiescent Shutdown 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 = 1400/RLIM The SP6648 datasheet specifications for RLIM give a range of 1750 to 4000 ohms. Using the IPEAK equation above gives an IPEAK range of IPEAK range = 350 to 800mA. 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 SP6648 evaluation board uses a Rlim value of 1.87K for an Ipeak = 750mA to allow the circuit to deliver up to 180mA for 1.3V input and 400mA for 2.6V input. Other values could be selected using the above relationships. 4) Using the LBON - Low Battery Output Function The Low Battery Output function, LBON, is programmed externally by the R3 and R4 resistor divider connected between Vbatt, the LBI input pin and GND. The LBON is an open drain output, which is active low and is pulled up by a 1M resistor R5 to Vout. When the LBI comparator falling threshold of 0.625V is reached, the LBON output goes low as determined by the relationship: LBON falling = Vbatt*R4/(R3 +R4) The SP6648 evaluation board R3 & R4 resistors have been set to trip for a falling battery threshold of about 2.0V. Using this relationship, other low battery threshold values can be set by the user. FIGURE 1: SP6648UEB COMPONENT PLACEMENT FIGURE 2: SP6648UEB PC LAYOUT TOP SIDE FIGURE 3: SP6648UEB PC LAYOUT BOTTOM SIDE TABLE1: SP6648EB LIST OF MATERIALS Ref. Des. Qty. Manufacturer 1 1 2 2 1 1 1 1 1 1 1 1 1 1 5 1 1 Sipex Corp. Sipex Corp. Kemet Kemet TDK Corp TDK Corp Sumida TDK Corp Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic Mill-Max Sullins Sullins Layout Size 146-6479-00 1"x1.5" SP6648EU uSO-8 T494C476K010AS "D" size T494V476K010AS "V" size C1608SL1H470K 0603 C1608X5R1A105M 0603 CDRH5D28-100 6.7x6.5x3.0mm RLF5018-100MR94 5.6x5.2x2.0mm ERJ-3EKF2053 0603 ERJ-3EKF2493 0603 ERJ-3EKF5493 0603 ERJ-3EKF2493 0603 ERJ-3GEYJ105 0603 ERJ-3EKF1871 0603 0300-115-01-4727100 .042 Dia PTC36SAAN .23x.12 STC02SYAN .2x.1 Part Number Component SP6648UEB Eval PC Board 10-pin uSOIC Step-Up DC/DC Conv 47uF 10V SM 0.3ohm ESR 47uF 10V low profile SM 0.3ohm ESR Ceramic 16V 47pF SM Ceramic 10V 1uF SM 0.02ohm ESR 10uH, 1.3A, 0.065ohm, SM Inductor 10uH, 0.94A, 0.067ohm, SM Inductor 205K ohm 1/8W 1% 0603 SM 124K ohm 1/8W 1% 0603 SM 549K ohm 1/8W 1% 0603 SM 249K ohm 1/8W 1% 0603 SM 1M ohm 1/8W 5% 0603 SM 1.87K ohm 1/8W 1% 0603 SM Test Point Female Pin 3-Pin Header Shunt Vendor Sipex 978-667-7800 Sipex Kemet 847-517-1030 Kemet 847-517-1030 TDK 847-803-6100 TDK 847-803-6100 Sumida 847-956-0666 TDK 847-803-6100 Digi-Key 800-344-4539 800-Digi-Key 800-Digi-Key 800-Digi-Key 800-Digi-Key 800-Digi-Key 800-Digi-Key 800-Digi-Key 800-Digi-Key U1 C1,2 C1,2 C3 C4 L1 L1 R1 R2 R3 R4 R5 RLIM TP J1 ORDERING INFORMATION Model Temperature Range Package Type SP6648UEB.................................. -40°C to +85°C...................SP6648 Evaluation Board SP6648EU.....................................-40°C to +85°C......................................10-pin µSOIC