19-2702; Rev 0; 12/02 MAX8504 Evaluation Kit Component List DESIGNATION QTY C1 1 C2 C3 C4 ♦ Integrated 0.25Ω Bypass PFET ♦ Externally Fixed 1.25V Output Voltage ♦ 600mA Output Current ♦ Adjustable Output Voltages (1.25V to 2.5V) ♦ 2.6V to 5.5V Input Voltage Range ♦ Low 0.1µA (typ) Quiescent Current in Shutdown Mode ♦ Evaluates MAX8500/MAX8503 Converters (Adjustable Output 0.4V to VIN) ♦ Surface-Mount Construction ♦ Fully Assembled and Tested DESCRIPTION 10µF ±20%, 6.3V X5R ceramic capacitor (0805) TDK C2012X5R0J106MT 1 0.1µF ±10%, 25V X7R ceramic capacitor (0603) TDK C1608X7R1E104KT 1 0.22µF ±10%, 10V X5R ceramic capacitor (0603) Taiyo Yuden LMK107BJ224KA 1 Features 4.7µF ±20%, 6.3V X5R ceramic capacitor (0805) TDK C2012X5R0J475MT or Taiyo Yuden JMK212BJ475MG C5 1 560pF ±5%, 50V C0G ceramic capacitor (0603) TDK C1608COG1H561JT or Taiyo Yuden UMK107CG561JZ C6 0 Not installed, capacitor (0603) J1 0 Not installed, scope-probe connector JU1, JU2, JU3 3 3-pin headers L1 1 4.7µH, 900mA inductor Sumida CDRH3D16-4R7NC R1, R2 0 Not installed, resistors (0603) R3 1 9.1kΩ ±5% resistor (0603) U1 1 MAX8504ETC 12-pin thin QFN 4mm x 4mm, topmark: AABS None 3 Shunts (JU1, JU2, JU3) None 1 MAX8504 PC board Ordering Information PART TEMP RANGE MAX8504EVKIT 0°C to 70°C IC PACKAGE 12 Thin QFN Component Suppliers SUPPLIER PHONE FAX WEBSITE 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.component. tdk.com Note: Please indicate that you are using the MAX8504 when contacting these component suppliers. Quick Start The MAX8504 EV kit is a fully assembled and tested surface-mount board. Follow the steps below for board operation. Do not turn on the power supply until all connections are completed. 1) Verify that a shunt is connected across pins 1 and 2 of jumper JU1 (output enabled). 2) Verify that a shunt is connected across pins 1 and 2 of jumper JU2 (PWM mode enabled). 3) Verify that a shunt is connected across pins 2 and 3 of jumper JU3 (high-power bypass mode disabled). 4) Connect a voltmeter across the VOUT and the GND pads to monitor the output voltage. ________________________________________________________________ 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: MAX8500/MAX8503/MAX8504 General Description The MAX8504 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board that demonstrates the MAX8504 1MHz pulse-width modulated (PWM) step-down DC-to-DC converter optimized for powering the power amplifier (PA) in wireless applications. The EV kit provides a 1.25V output from a 2.6V to 5.5V input range and can deliver 600mA of load current. The output voltage can be reconfigured to voltages in the range of 1.25V to 2.5V by adding two resistors. The MAX8504 EV kit can also be used to evaluate the MAX8500 and the MAX8503 converters that can dynamically control the output voltage from 0.4V to VIN. Evaluates: MAX8500/MAX8503/MAX8504 MAX8504 Evaluation Kit 5) Connect a 2.6V to 5.5V power supply to the VIN pad. Connect the power-supply ground terminal to the GND pad. 6) Turn on the power supply and verify that the output voltage is 1.25V. Detailed Description The MAX8504 EV kit circuit board demonstrates the MAX8504 1MHz PWM step-down DC-to-DC converter circuit that is optimized to power a PA in wireless applications. The EV kit requires a power supply with a 2.6V to 5.5V output range. The EV kit is configured for an output voltage of 1.25V and can provide 600mA of load current. The output voltage can be reconfigured by installing feedback resistors R1 and R2 on the board. The EV kit board features jumpers that enable the user to configure the shutdown, SKIP/PWM, and high-power (HP) bypass modes. The MAX8504 EV kit board can also be used to evaluate the MAX8500/MAX8503 converters that can dynamically control the output voltage in the range of 0.4V to VIN from an analog control signal supplied by the user. SKIP/PWM Mode Installing a shunt across pins 2 and 3 of jumper JU2 enables skip-mode operation. This allows automatic PWM control at medium and heavy current loads and skip mode at light current loads to improve efficiency and reduce quiescent current. Installing a shunt across pins 1 and 2 of JU2 enables forced-PWM operation. Forced-PWM operation is desirable in sensitive RF and data-acquisition applications to ensure that switching harmonics do not interfere with sensitive IF and data sampling frequencies. Forced-PWM operation uses higher supply current with no load compared to skip mode. See Table 2 for JU2 configuration. Table 2. Jumper JU2 (SKIP/PWM) SHUNT LOCATION SKIP PIN EV KIT OPERATION 1 and 2 Connected to VIN PWM operation at all loads 2 and 3 Connected to GND SKIP mode at light loads and PWM mode at medium and heavy loads Output Voltage The MAX8504 EV kit circuit is configured to regulate the output voltage to 1.25V. The output voltage (VOUT) can be adjusted in the range of 1.25V to 2.5V by cutting open the short across R1 and installing feedback resistors, R1 and R2. Select feedback resistor R2 between 5kΩ and 50kΩ, and R1 is determined by the following equation: R1 = R2 (VOUT / VFB - 1) where VFB = 1.25V and VOUT is the desired output voltage. Shutdown Mode The EV kit contains jumper JU1 to allow the user to switch the MAX8504 converter from enable to shutdown mode. Shutdown mode reduces the supply current to 0.1µA (typ) and sets the output voltage to 0V. See Table 1 for JU1 configurations. Table 1. Jumper JU1 (Shutdown) SHUNT LOCATION 2 SHDN PIN EV KIT OPERATION Output enabled, VOUT = 1.25V 1 and 2 Connected to VIN 2 and 3 Connected to GND Shutdown, VOUT = 0V High-Power Bypass Mode Jumper JU3 allows the user to enable or disable the high-power bypass mode of the MAX8504 converter. When the high-power mode is enabled, the converter stops regulating the output voltage and the output voltage VOUT is equal to the input voltage VIN. When the high-power mode is disabled, the converter regulates the output voltage to the programmed voltage. See Table 3 for JU3 configuration. Removing the shunt on jumper JU3 and applying a CMOS logic-level signal to the HP pad on the EV kit board can also control the high-power bypass mode. Table 3. Jumper JU3 (High-Power Mode) SHUNT LOCATION HP PIN 1 and 2 Connected to VIN High-power bypass mode enabled, VOUT = VIN 2 and 3 Connected to GND High-power bypass mode disabled, VOUT = 1.25V Connected to HP pad Output controlled by the user (user-supplied control signal must be connected to HP pad). None EV KIT OPERATION _______________________________________________________________________________________ MAX8504 Evaluation Kit 3) Install a 0.01µF (0603 case) capacitor on R2. 4) Connect a DC voltage signal to the REFIN pad to set the output voltage VOUT (VOUT = gain x REFIN). 5) Install a shunt across pins 1 and 2 of JU3. 6) Refer to the Compensation, Stability, and Output Capacitor section of the MAX8500–MAX8504 data sheet to verify component values for the application. Table 4. Alternate Converters PART GAIN IC TOP MARK MAX8500ETC 1.76x AABQ MAX8503ETC 2x AABU MAX8504ETC* *Installed. N/A AABS J1 VIN GND 8 C1 10µF C2 0.1µF 9 BATTP OUT BATT LX 2 VOUT REFIN GND REF 10 VOUT C4 4.7µF VIN U1 C3 0.22µF L1 4.7µH 7 1 12 2 MAX8504 SHDN R1 SHORT (PC TRACE) JU1 3 3 VIN FB R2 OPEN 11 1 2 SKIP VIN HP 1 2 3 GND JU2 3 JU3 5 HP 4 GND PGND 1 6 COMP C6 OPEN R3 9.1kΩ C5 560pF Figure 1. MAX8504 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX8500/MAX8503/MAX8504 Evaluating MAX8500/MAX8503 The MAX8504 EV kit circuit board comes with the MAX8504 converter installed. The MAX8504 EV kit board can also be used to evaluate the MAX8500/ MAX8503 converters, which do not require feedback resistors to set the output voltage. An analog control signal connected to the REFIN pad dynamically adjusts the output voltage from 0.4V to VIN. The gain from REFIN to VOUT is internally set to 1.76 (MAX8500) or 2 (MAX8503). See Table 4 for details on the various features of the MAX8500/MAX8503/MAX8504 converters. Follow these steps to evaluate the MAX8500/MAX8503 converters on the MAX8504 EV kit board: 1) Replace the MAX8504 converter (U1) with the alternate converter (Table 4). 2) Cut open the short across R1. Evaluates: MAX8500/MAX8503/MAX8504 MAX8504 Evaluation Kit Figure 2. MAX8504 EV Kit Component Placement Guide— Component Side Figure 3. MAX8504 EV Kit PC Board Layout—Component Side Figure 4. MAX8504 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 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.