19-3076; Rev 0; 11/03 MAX5035 Evaluation Kit The MAX5035 MAXPower IC features a built-in highside switch and an automatic pulse-skipping mode operation. The MAX5035 EV kit demonstrates low quiescent current and high efficiency up to 92%. The MAX5035 MAXPower IC switches at 125kHz. Warning: The MAX5035 EV kit is designed to operate with high voltages. Dangerous voltages are present on this EV kit and on equipment connected to it. Users who power up this EV kit or power the sources connected to it must be careful to follow appropriate safety procedures when working with high-voltage electrical equipment. Under severe fault or failure conditions, this EV kit may dissipate large amounts of power, which could result in the mechanical ejection of a component or of component debris at high velocity. Operate this EV kit with care to avoid possible personal injury. Features ♦ 8V to 76V Input Voltage Range ♦ 5V Output at Up to 1A ♦ 92% Efficiency ♦ Adjustable Output Voltage Through Resistive Voltage-Divider ♦ No Load Quiescent Current: 794µA at VIN = 76V 582µA at VIN = 42V 392µA at VIN = 12V ♦ 125kHz Switching Frequency ♦ Automatic Pulse-Skipping Mode ♦ Fully Assembled and Tested Ordering Information PART TEMP RANGE IC-PACKAGE MAX5035EVKIT 0°C to +70°C 8 SO Component List DESIGNATION QTY C1 C2 1 1 DESCRIPTION 68µF ±20%, 100V electrolytic capacitor (12.5 x 13.5) Panasonic EEVFK2A680Q 68µF ±20%, 10V tantalum capacitor (C) AVX TPSD686M010R0100 (0.100 ESR) or Vishay 594D686X0010C2T (0.1 ESR) DESIGNATION QTY DESCRIPTION D1 1 80V, 5A Schottky diode (D0-204AR) International Rectifier 50SQ080 L1 1 100µH, 1.8A inductor Coilcraft Inc. DO5022P-104 R1 1 41.2kΩ ±1% resistor (0805) R2 1 13.3kΩ ±1% resistor (0805) R3 1 130kΩ ±1% resistor (0805) R4 0 Not installed, resistor (0805) R5 1 45.3kΩ ±1% resistor (0603) C3, C4 2 0.1µF ±10%, 50V X7R ceramic capacitors (0603) TDK C1608X7R1H104K U1 1 MAX5035DUSA (8-pin SO) JU1 1 3-pin header C5 0 Not installed, capacitor (0805) None 1 Shunt (JU1) 0.2µF ±10%, 100V X7R ceramic capacitor (1206) AVX 12061C224KAT None 1 MAX5035 PC board C6 1 ________________________________________________________________ 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: MAX5035 General Description The MAX5035 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board that contains a step-down DC-DC switching-regulator circuit. The circuit utilizes a MAX5035 adjustable converter configured for a 5V output and provides up to 1A of current. The converter operates from a wide input range of 8V to 76V. Evaluates: MAX5035 MAX5035 Evaluation Kit Component Suppliers SUPPLIER PHONE FAX WEBSITE AVX 843-946-0238 843-626-3123 www.avxcorp.com Coilcraft 847-639-6400 847-639-1469 www.coilcraft.com International Rectifier 310-322-3331 310-726-8721 www.irf.com Panasonic 714-373-7366 714-737-7323 www.panasonic.com TDK 847-803-6100 847-390-4405 www.component.tdk.com Vishay 402-563-6866 402-563-6296 www.vishay.com Note: Please indicate that you are using the MAX5035 when contacting these component suppliers. Quick Start The MAX5035 EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supply until all connections are completed. mately 85mA) the MAX5035 operates in pulse-skipping mode, and under heavy loads it automatically enters PWM mode. The circuit switches at 125kHz. The EV kit features a PC board pad for the SHDN signal to interface with an external controller. Startup delays can be evaluated by installing resistor R4 and capacitor C5. 5V Output Verification 1) Verify that a shunt is across pins 1 and 2 of jumper JU1 (S H D N). 2) Connect a voltmeter to the VOUT pad and GND pad. 3) Connect a 12V DC power supply to the VIN pad. Connect the supply ground to the GND pad. 4) Turn on the power supply and verify that VOUT is at 5V. For instructions on selecting the feedback resistors for other output voltages, see the Evaluating Other Output Voltages section. Detailed Description The MAX5035 EV kit features a 5W step-down DC-DC switching-regulator circuit. The circuit uses a MAX5035 adjustable output-voltage converter to provide an output voltage of 5V and can deliver up to 1A of current to the output. The user must provide an 8V to 76V DC source that is capable of supplying at least 2A of current to power the circuit. The MAX5035 converter’s built-in, high-side, low onresistance DMOS transistor reduces component count while maximizing efficiency. Under light loads (approxi- 2 Jumper Selection Shutdown Mode The MAX5035 EV kit features a shutdown mode that reduces the MAX5035 quiescent current to 10µA (typ), thus reducing the power drain during shutdown mode. The 3-pin jumper, JU1, selects the shutdown mode for the MAX5035 EV kit. Table 1 lists the selectable jumper options. Table 1. Jumper JU1 Functions SHUNT LOCATION SHDN PIN MAX5035 EV KIT OUTPUT 1 and 2 Connected to VIN through R3 MAX5035 enabled 2 and 3 Connected to GND MAX5035 disabled None External controller connected to SHDN pad Logic high = enabled, Logic low = disabled Caution: Do not connect an external controller to the SHDN pad while a shunt is on jumper JU1 since the external con- _______________________________________________________________________________________ MAX5035 Evaluation Kit The MAX5035 EV kit’s startup delay can also be utilized to sequence two MAX5035 EV kits. Components R4EVKIT1, R4EVKIT2, C5EVKIT1 and C5EVKIT2 determine the startup delay between the two EV kits. The following equation can be used to select values for R4 and C5: Time _ delay C5 = . 1 69 V −R4 x ln 1 − VSHUT _ DOWN Startup Delays/ Sequencing Two DC-DC Converters where Time_delay is the desired startup delay time, VSHUT_DOWN is the desired startup voltage at the SHDN pad on the EV kit and 1.69V (typ) is the on/off threshold voltage of the MAX5035. The MAX5035 EV kit can be configured for various startup delays. To evaluate a startup delay, cut open the PC board trace shorting resistor R4 and install the desired surface-mount resistor (0805 case). Capacitor C5 (0805 case) must also be selected and installed. Refer to the MAX5035 data sheet’s Shutdown Mode and Undervoltage Lockout (UVLO) sections to select values for resistor R4 and capacitor C5. 3 FB SGND 4 R2 13.3kΩ 1% VIN R3 130kΩ 1% SHDN JU1 U1 R4 SHORT PC TRACE 1 2 3 R5 45.3kΩ 1% R1 41.2kΩ 1% MAX5035 5 BST SHDN 1 C5 OPEN C3 0.1µF 7 VIN 2 C1 68µF 100V C6 0.22µF 100V VIN VD LX L1 100µH 8 VOUT C4 0.1µF GND D1 C2 68µF 10V 6 GND GND Figure 1. MAX5035 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX5035 Evaluating Other Output Voltages The MAX5035 step-down DC-DC switching regulator output is set to 5V by feedback resistors R1 and R2. To generate output voltages other than 5V (1.25V to 12V), select different external voltage-divider resistors for R1 and R2. Refer to the Setting the Output Voltage section in the MAX5035 data sheet for instructions on selecting the resistors. The minimum input voltage for a given output voltage is maximum duty-cycle dependent for that input voltage. Refer to the MAX5035 data sheet for additional information. Evaluates: MAX5035 MAX5035 Evaluation Kit Figure 2. MAX5035 EV Kit Component Placement Guide— Component Side Figure 3. MAX5035 EV Kit PC Board Layout—Component Side Figure 4. MAX5035 EV Kit PC Board Layout—Solder Side Figure 5. MAX5035 EV Kit Component Placement Guide— 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 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.