19-2253; Rev 0; 12/01 MAX5026 Evaluation Kit The MAX5026 evaluation kit (EV kit) provides a +30V output voltage from a +3V to +11V input source. It delivers up to 6mA output current, depending on the input voltage. The MAX5026 is a constant-frequency, pulse-width-modulating (PWM), current-mode step-up voltage converter with an internal power switch that operates at 500kHz. This EV kit demonstrates the lownoise performance of the device. The MAX5026 EV kit is a fully assembled and tested surface-mount circuit board. With modifications, this EV kit can also be used to evaluate MAX5025/ MAX5027/MAX5028. The EV kit can be used to evaluate other output voltages by changing the feedback resistors. Features ♦ +3V to +11V Input Voltage Range (MAX5026/MAX5028) ♦ +4.5V to +11V Input Voltage Range (MAX5025/MAX5027) ♦ Output Voltage: Adjustable Output Voltage Up to +36V (MAX5025/MAX5026) +30V Fixed Output Voltage (MAX5027/MAX5028) ♦ Low Switching Noise ♦ 500kHz Switching Frequency ♦ Less than 1mVp-p High-Frequency Output Switching Ripple at 2mA Load ♦ Up to 6mA Output Current with +5V Input Component List DESIGNATION C1 QTY 1 C2, C3 2 C4, C5 0 L1 1 DESCRIPTION 4.7µF, 16V, X5R, 20% ceramic capacitor (1206) Taiyo Yuden EMK316BJ475ML ♦ 6-Pin SOT23 Package ♦ Surface-Mount Construction ♦ Fully Assembled and Tested 1µF, 50V, X7R, 10% ceramic capacitors (1210) Taiyo Yuden UMK325BJ105KH TDK C3225X7R1H105K Murata GRM42-2X7R105K050AD Not installed, capacitor (1210) 47µH ±20% power inductor Toko A915BY-470M Sumida CDRH4D28-470 D1 1 0.5A, 40V Schottky diode (SOT23) Zetex ZHCS500 R1 1 147kΩ ±1% resistor (0603) R2 1 6.34kΩ ±1% resistor (0603) R3 1 100Ω ±5% resistor (0805) U1 1 MAX5026EUT (6-Pin SOT23) JU1 1 3-pin header (JU1) J1 1 Oscilloscope jack None 1 Shunt None 1 MAX5026 PC board None 1 MAX5026 EV kit data sheet None 1 MAX5026 data sheet Ordering Information PART MAX5026EVKIT TEMP. RANGE o o 0 C to +70 C IC PACKAGE 6 SOT23-6 Note: To evaluate the MAX5025/MAX5027/MAX5028, request a MAX5025EUT/MAX5027EUT/MAX5028EUT free sample with the MAX5026EVKIT. ________________________________________________________________ Maxim Integrated Products 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. 1 Evaluates: MAX5025–MAX5028 General Description Evaluates: MAX5025–MAX5028 MAX5026 Evaluation Kit Component Suppliers SUPPLIER PHONE FAX WEBSITE Murata 770-436-1300 770-436-3030 www.murata.com Sumida 847-545-6700 847-545-6720 www.sumida.com Taiyo Yuden 800-348-2496 847-925-0899 www.t-yuden.com TDK 847-803-6100 847-390-4405 www.tdk.com Toko 847-297-0070 847-699-1194 www.tokoam.com Zetex 631-543-7100 631-864-7630 www.zetex.com Note: Please indicate that you are using the MAX5025–MAX5028 when contacting these component suppliers. Quick Start The MAX5026 EV kit is a fully assembled and tested surface-mount board. Follow the steps below to verify board operation. Do not turn on the power supply until all connections are completed. Evaluating MAX5026 1) Verify that there is a shunt across JU1 (SHDN) pins 1 and 2. 2) Connect a voltmeter and load (if any) to the VOUT pad (and/or plug an oscilloscope probe into the oscilloscope jack). 3) Connect a +3V to +11V power supply to the VIN pad. Connect the power-supply ground to the GND pad closest to VIN. 4) Turn on the power supply and verify that the output voltage is approximately +30V. the pads labeled C5. Without the 10µF capacitor, the peak-to-peak low-frequency noise is about 20mV. The peak-to-peak low-frequency noise drops to 3mV when the 10µF capacitor is included. Evaluating Other Output Voltages The default output for the MAX5026 EV kit is +30V. To generate output voltages other than +30V with either the MAX5025EUT or MAX5026EUT, change feedback resistors R1 and R2. Limit the current through R1 and R2 to about 200µA. R1 = R2 [(VOUT /1.25V) - 1]. Evaluating MAX5027/MAX5028 The MAX5026 EV kit can also be used to evaluate the MAX5027/MAX5028 boost converters with fixed +30V output. To evaluate MAX5027/MAX5028, remove the feedback resistors R1 and R2, short the two pads of R1, and replace the MAX5026EUT with a MAX5027EUT/ MAX5028EUT. To evaluate other output voltages, refer to the Evaluating Other Output Voltages section. Detailed Description Shutdown Function The MAX5026 EV kit contains a boost converter. The circuit provides a +30V output with less than 2mVp-p highfrequency ripple from a +3V to +11V input voltage, and delivers up to 6mA. The setting of jumper JU1 selects the circuit operating modes. Table 1 shows the functions of jumper JU1. Noise Performance The MAX5026 EV kit is specifically designed for lownoise performance. An RC filter at the regulator’s output reduces its noise further. To observe this filtered output, monitor the signal at oscilloscope jack J1. The high-frequency output ripple voltage is less than 1mVp-p at 2mA load current. Extra capacitor pads (C4 and C5) are provided for further noise reduction. To reduce lowfrequency noise, add a 10µF electrolytic capacitor at 2 VOUT 1mV/div AC-COUPLED LX PIN 20V/div 0V IL 200mA/div 0mA 1µs/div MAX5026, VCC = 5V, VOUT = +30V, ILOAD = 2mA Figure 1. Medium-Load Switching Waveform with RC Filter _______________________________________________________________________________________ MAX5026 Evaluation Kit SHDN PIN SHUNT LOCATION MAX5026 OUTPUT 1 and 2 Connected to VIN MAX5026 enabled, VOUT = +30V 2 and 3 Connected to GND Shutdown mode, VOUT = VIN - VD, where VD is the diode forward-voltage drop Connected to SHDN pad External logic signal enables or disables the MAX5026 output Open Evaluates: MAX5025–MAX5028 Table 1. Jumper JU1 Functions L1 47µH J1 1 D1 5 LX VCC C1 4.7µF 16V GND 6 JU1 R3 100Ω 3 VOUT MAX5026 PGND GND SHDN FB 2 VIN 1 1 L U1 1 SHDN VOUT 2 VIN 4 2 3 2 R R1 147kΩ 1% C4 C2 1.0µF OPEN 50V C5 C3 OPEN 1.0µF 50V GND 3 R2 6.34kΩ 1% Figure 2. MAX5026 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX5025–MAX5028 MAX5026 Evaluation Kit 1.0" 1.0" Figure 3. MAX5026 EV Kit Component Placement Guide—Top Silkscreen Figure 4. MAX5026 EV Kit PC Board Layout—Component Side 1.0" Figure 5. MAX5026 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 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.