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| 19-3613; Rev 0; 3/05 MAX8571 Evaluation Kit General Description The MAX8571 evaluation kit (EV kit) contains a fully assembled and tested circuit for evaluating the MAX8571 step-up converter. This circuit operates with 2.7V to 5.5V input supply and provides a regulated 18V output at up to 10mA. The output voltage is adjustable from VCC to 28V by changing resistors on the EV kit. The MAX8571 EV kit contains a second unpopulated circuit to accomodate a larger inductor and diode for the higher-current-limited MAX8574 and MAX8575. Either circuit can be used to evaluate any of the parts in the MAX8570 family. Features o 18V Output Voltage, Adjustable from VCC Up to 28V o Built-In Safety Features Protect Against Output Faults o True ShutdownTM o 87% Efficiency o Up to 800kHz Switching Frequency o 0.01A Shutdown Current o Fully Assembled and Tested Evaluates: MAX8570-MAX8575 Ordering Information PART MAX8571EVKIT TEMP RANGE 0C to +70C IC PACKAGE 6 SOT23-6 True Shutdown is a trademark of Maxim Integrated Products, Inc. Component List DESIGNATION QTY DESCRIPTION 1F 20%, 6.3V X5R ceramic capacitor (0402) TDK C1005X5R0J105M Panasonic ECJ0EB0J105M 4.7F 10%, 6.3V X5R ceramic capacitor (0603) TDK C1608X5R0J475K Panasonic ECJ1VB0J475K 1F 10%, 50V X7R ceramic capacitor (1206) TDK C3216X7R1H105K 10pF 5%, 50V C0G ceramic capacitor (0402) Murata GRM1555C1H100J TDK C1005C0G1H100J Not installed, ceramic capacitor (1206) Not installed, ceramic capacitors (0402) Not installed, ceramic capacitor (0603) DESIGNATION D1 D2 JU1 JU3 L1 L2 R1 R2 R3, R4 U1 U2 None None QTY 1 0 1 0 1 0 1 1 0 1 0 1 1 DESCRIPTION 200mA, 30V Schottky diode (SOD-323) Central CMDSH2-3 Not installed, diode (SOD-123) 3-pin header Not installed, 3-pin header 22H inductor Murata LQH32CN220K23 Not installed, inductor 3.92M 1% resistor (0402) 287k 1% resistor (0402) Not installed, resistors (0402) MAX8571EUT (6-pin SOT23) Not installed, MAX857_EUT (6-pin SOT23) Shunt, 2 position MAX8571 EV kit PC board C1 1 C2 1 C3 1 C4 1 C5 C6, C8 C7 0 0 0 ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. MAX8571 Evaluation Kit Evaluates: MAX8570-MAX8575 Component Suppliers SUPPLIER Central Semiconductor Kamaya Murata Panasonic TDK TOKO Vishay PHONE 631-435-1110 260-489-1533 814-237-1431 714-373-7939 847-803-6100 847-297-0070 402-563-6866 WEBSITE www.centralsemi.com www.kamaya.com www.murata.com www.panasonic.com www.component.tdk.com www.toko.com www.vishay.com Note: Indicate that you are using the MAX8571 when contacting these component suppliers. Quick Start Recommended Equipment * * * Power supply or battery capable of supplying 2.7V to 5.5V at up to 100mA Load (up to 10mA) Voltmeter Table 1. JU1 and JU3 Jumper Settings JU1/JU3 1-2 2-3 FUNCTION Enable Shutdown Table 2. JU2 and JU4 Settings Procedure JU2/JU4 Short Open INPUT POWER VCC_ only BATT_ and VCC_ TRUE SHUTDOWN Yes No The MAX8571 EV kit is fully assembled and tested. Follow these steps to verify board operation: 1) Preset the power supply to between 2.7V and 5.5V. Turn off the power supply. Do not turn on the power supply until all connections are completed. 2) Connect the positive power-supply lead to the EV kit terminal labeled VCC1. 3) Connect the negative power-supply lead to the EV kit terminal labeled GND1. 4) Connect the load and voltmeter between EV kit terminals OUT1 and GND1. 5) Verify that jumper JU1 is shorted across pins 1 and 2. 6) Turn on the power supply. 7) Verify that the voltmeter reads 18V. select R2 from 10k to 600k and calculate R1 with the following equation: V R1 = R2 OUT - 1 VFB where VFB = 1.226V and VOUT can range from VCC to 28V. For best accuracy, ensure that the bias current through the feedback resistors is at least 2A. The output voltage for circuit 2 is set similarly, only using resistors R4 and R3. When evaluating the ICs with a preset output voltage (MAX8572/MAX8573/ MAX8575), short R1/R4 and leave R2/R3 open. Detailed Description Enable/Shutdown The low-power True Shutdown feature is evaluated using the jumpers provided on the EV kit (see Table 1). Short pins 1-2 of JU1 to enable circuit 1, or short pins 23 for shutdown. Short pins 1-2 of JU3 to enable circuit 2, or short pins 2-3 for shutdown. Using a Separate Supply for the Inductor Separate power supplies can be used for the IC and the inductor. This allows power to be drawn from a separate supply (i.e., a battery) that may range above or below the 2.7V to 5.5V operating range of VCC. When using a separate inductor supply for circuit 1, cut the trace shorting JU2 and connect the inductor supply to the EV kit pad labeled BATT1 (see Table 2). For circuit 2, cut the trace shorting JU4 and connect the inductor supply to the EV kit pad labeled BATT2. A VCC_ supply between 2.7V and 5.5V is still needed to power the IC; Setting the Output Voltage The output voltage is adjustable from VCC to 28V by using a resistor voltage-divider (R1 and R2). For circuit 1, 2 _______________________________________________________________________________________ MAX8571 Evaluation Kit Evaluates: MAX8570-MAX8575 L1 22H BATT1 JU1 321 3 U1 D1 OUT1 R1 3.92M C4 10pF C3 1F GND1 JU2 VCC1 C1 1F MAX8571 5 SHDN SW 4 6 VCC LX 1 2 GND FB C2 4.7F GND1 R2 287k CIRCUIT 1 L2 OPEN BATT2 JU3 321 3 U2 D2 OUT2 C5 OPEN GND2 JU4 VCC2 C8 OPEN MAX857_ 5 SHDN SW 6 4 VCC LX 2 1 GND FB C7 OPEN R4 OPEN C6 OPEN GND2 R3 OPEN CIRCUIT 2 Figure 1. MAX8571 EV Kit Schematic however, most of the power is drawn from BATT_. Note that in this configuration, the output is no longer disconnected from the input during shutdown. In shutdown, the output voltage goes to a diode drop below the inductor supply voltage. Evaluating the MAX8570/MAX8572-MAX8575 The MAX8571 EV kit can be used to evaluate the entire MAX8570 family of step-up converters. The second (right-side) circuit on the PC board accommodates a larger inductor and diode for use with the MAX8574 and MAX8575, which have an inductor peak current limit of 500mA and can supply higher output current. When changing to a part with a different current limit, refer to the MAX8570-MAX8575 data sheet for information on selecting external components. When using parts with a preset output voltage (MAX8572/ MAX8573/MAX8575), short R1 and remove R2 (for circuit 2, short R4 and leave R3 open). _______________________________________________________________________________________ 3 MAX8571 Evaluation Kit Evaluates: MAX8570-MAX8575 Figure 2. MAX8571 EV Kit Component Placement Guide-- Component Side Figure 3. MAX8571 EV Kit PC Board Layout--Component Side Figure 4. MAX8571 EV Kit PC Board Layout--Solder Side Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 4 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc. |
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