EV2105DJ-00A 800mA Synchronous Buck Step-Down Converter Monolithic Power Systems INITIAL RELEASE GENERAL DESCRIPTION FEATURES The EV2105 evaluation board is designed for low dropout step down converter applications. It implements the MP2105 1MHz Fixed Frequency, Current Mode, PWM step-down converter. The device integrates a main switch and a synchronous rectifier for high efficiency without an external Schottky diode. It is ideal for powering portable equipments that runs from a single cell Lithium-Ion (Li+) Battery. It can supply 800mA of load current from a 2.5V to 6V input voltage. The output voltage can be regulated as low as 0.6V. In 100% Duty Cycle Dropout operation, it works with minimum input voltage as low as output voltage. • • • • • • • • • ELECTRICAL SPECIFICATION Parameter Input Voltage Range Output Voltage Load Max Symbol Value Units VIN VOUT IOUT 2.5 to 6.0 1.8 800 V V mA High Efficiency: Up to 95% 800mA Available Load Current 2.5V to 6V Input Voltage Range Output Voltage as Low as 0.6V 100% Duty Cycle in Dropout Short Circuit Protection Thermal Fault Protection <0.1µA Shutdown Current Programmable Enable Control APPLICATIONS • Cellular and Smart Phones Microprocessors/DSP Core Supplies PDAs MP3 Players Digital Still and Video Cameras Portable Instruments , “MPS”, “Monolithic Power Systems”, and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. EV2105DJ-00A EVALUATION BOARD Efficiency vs Load Current 100 90 VIN = 3.3V EFFICIENCY (%) 80 VIN = 4.2V 70 60 50 40 30 20 10 Dimensions (2.0”X x 2.0”Y x 0.5”Z) Board Number MPS IC Number EV2105DJ-00A MP2105DJ 12/04, Rev. 1.0 www.MonolithicPower.com 0 10 100 LOAD CURRENT (mA) 1000 MP2105-EC01 1 EV2105DJ-00A – 800mA SYNCHRONOUS BUCK STEP-DOWN CONVERTER INITIAL RELEASE EVALUATION BOARD SCHEMATIC J1 INPUT 2.5V - 6V IN R3 NS OFF ON VOUT SW MP2105 EN GND FB C3 NS EV2105DJ-00A_S01 EV2105DJ-00A BILL OF MATERIALS Qty Ref Value Description Package 1 C1 4.7µF Ceramic Cap, 6.3V, X5R SM0805 AVX 08056D475KAT2A 1 C2 10µF Ceramic Cap, 6.3V, X5R SM0805 AVX 08056D106KAT2A 1 C3 Do Not Stuff 1 J1 Jumper 1 L1 4.7µH 1.15A SMD Sumida CR43-4R7 1 R1 499kΩ Film Res, 1% SM0805 Yageo 9C08052A3003FK HFT 1 R2 249kΩ Film Res, 1% SM0805 Panasonic ERJ-6ENF1503V 1 R3 Do Not Stuff 1 U1 DC-DC Converter SOT23-5 MPS 12/04, Rev. 1.0 www.MonolithicPower.com Manufacturer Manufacturer P/N MP2105DJ 2 EV2105DJ-00A – 800mA SYNCHRONOUS BUCK STEP-DOWN CONVERTER INITIAL RELEASE PRINTED CIRCUIT BOARD LAYOUT Figure 1—Top Silk Layer Figure 2—Top Layer Figure 3—Bottom Silk Layer Figure 4—Bottom Layer 12/04, Rev. 1.0 www.MonolithicPower.com 3 EV2105DJ-00A – 800mA SYNCHRONOUS BUCK STEP-DOWN CONVERTER INITIAL RELEASE QUICK START GUIDE The output voltage of this board is set to 1.8V. The board layout accommodates most commonly used inductors and output capacitors. 1. Attach Positive end and Negative end of Load to VOUT and GND pins respectively. 2. Attach Input Voltage 2.5V ≤ VIN ≤ 6V and Input Ground to VIN and GND pins respectively. 3. To enable the MP2105 apply a voltage, 1.5V ≤ VEN ≤ 6V, to the EN pin. To disable the MP2105 apply a voltage, VEN < 0.3V, to the EN pin. The default setting for the jumper J1 on the board connects VIN to the EN pin. With this configuration, the part will operate without applying any external voltage to the EN pin. 4. The Output Voltage VOUT can be changed by varying R2. Calculate the new value by formula: R2 = R1 ⎛ VOUT ⎜⎜ ⎝ VFB ⎞ ⎟⎟ − 1 ⎠ Where VFB = 0.6V and R1 = 499kΩ. Example: For VOUT = 2.5V: R2 = 499kΩ = 174kΩ ⎛ 2. 5 V ⎞ ⎜ ⎟ −1 ⎝ 0 .6 V ⎠ Therefore, use a 174kΩ standard 1% value. NOTICE: MPS believes the information in this document to be accurate and reliable. However, it is subject to change without notice. Contact MPS for current specifications. MPS encourages users of its products to ensure that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS cannot assume any legal responsibility for any said applications. EV2105DJ-00A Rev. 1.0 Monolithic Power Systems, Inc. 12/2/04 983 University Avenue, Building A, Los Gatos, CA 95032 USA © 2004 MPS, Inc. Tel: 408-357-6600 ♦ Fax: 408-357-6601 ♦ www.MonolithicPower.com 4