19-2701; Rev 0; 12/02 MAX1993 Evaluation Kit Features ♦ 7V to 24V Input Voltage Range ♦ Preset 1.8V/2.5V Output Voltages (Adjustable from 0.7V to 5.5V, MAX1992) ♦ Dynamically Selectable Output Voltages 1.0V/1.5V (Adjustable from 0.7V to 5.5V, MAX1993) ♦ 4A Output Current ♦ 300kHz Switching Frequency ♦ Selectable Inductor Saturation Protection ♦ Power-Good Output ♦ Selectable Overvoltage/Undervoltage Protection ♦ Low-Profile Components ♦ Fully Assembled and Tested This EV kit is a fully assembled and tested circuit board. It also allows the evaluation of other dynamically adjustable output voltages in the 0.7V to 5.5V range by changing R6, R7, and R8 resistors. This EV kit can also be used to evaluate the MAX1992, which has preset 1.8V/2.5V output voltages. Ordering Information PART TEMP RANGE MAX1993EVKIT 0°C to +70°C IC PACKAGE 24 Thin QFN 4mm × 4mm Component List DESIGNATION QTY DESCRIPTION C1 1 10µF, 25V ceramic capacitor (1812) Taiyo Yuden TMK432BJ106KM or TDK C4532X5R1E106M C2 1 270µF, 2.5V, 9mΩ low-ESR capacitor Sanyo 2R5TPE220M9 C3, C7 2 1µF, 10V X5R ceramic capacitors (0805) Taiyo Yuden LMK212BJ105KG or TDK C2012X5R105M C4 1 0.1µF ceramic capacitor (0603) C5 1 470pF ceramic capacitor (0603) 1 0.22µF, 16V X5R ceramic capacitor (0805) Taiyo Yuden EMK212BJ224KG C6 C8 C9 1 1000pF ceramic capacitor (0603) 1 10µF, 6.3V X5R ceramic capacitor (0805) TDK C2012X5R0J106M or Taiyo Yuden AMK212BJ106MG C10, C11, C12 0 Not installed (0603) D1 1 1A, 30V Schottky diode Nihon EP10QY03 or Nihon EC10QS03 D2 1 JU1, JU2, JU3 3 DESIGNATION QTY JU4 DESCRIPTION 1 4-pin header L1 1 2.5µH, 7.5A power inductor Sumida CDRH104R-2R5 N1A, N1B 2 Dual N-channel MOSFETs Fairchild FDS6982A R1, R11, R12, R22 4 0Ω resistors (0603) R2, R3, R13–R17, R20, R21 0 Not installed (0603) R4 1 100kΩ ±1% resistor (0603 49.9kΩ ±1% resistor (0603) R5 1 R6, R7 2 75kΩ ±1% resistors (0603) R8 1 150kΩ ±1% resistor (0603) R9 1 100kΩ ±5% resistor (0603) R10 1 20Ω ±5% resistor (0805) R18 1 0.015Ω ±1%, 1/2W resistor (2010) IRC LR2010-01-R015-F or Dale WSL-2010-R015F R19 0 Not installed (short PC trace) (0805) U1 1 MAX1993ETG (24-pin thin QFN) 100mA, 30V Schottky diode Central Semiconductor CMPSH-3 None 4 Shunts None 4 Rubber feet 3-pin headers None 1 MAX1993 PC board ________________________________________________________________ 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: MAX1992/MAX1993 General Description The MAX1993 evaluation kit (EV kit) demonstrates the MAX1993’s standard 4A application circuit. This DC-toDC converter steps down high-voltage batteries and/or AC adapters, generating a precision, low-voltage rail for use as chipset, DRAM, and other low-voltage supplies. The MAX1993 EV kit provides a dynamically adjustable 1.0V/1.5V output voltage from 7V to 24V battery input range. It delivers up to 4A output current with greater than 90% efficiency. The EV kit operates at 300kHz switching frequency and has superior line- and loadtransient response. Evaluates: MAX1992/MAX1993 MAX1993 Evaluation Kit Component Suppliers PHONE FAX WEBSITE Central Semiconductor SUPPLIER 516-435-1110 516-435-1824 www.centralsemi.com Dale-Vishay 402-564-3131 402-563-6296 www.vishay.com IRC 361-992-7900 361-992-3377 www.irctt.com Fairchild 408-721-2181 408-721-1635 www.fairchildsemi.com Nihon 847-843-7500 847-843-2798 www.niec.co.jp Taiyo Yuden 408-573-4150 408-573-4159 www.t-yuden.com TDK 847-390-4373 847-390-4428 www.component.tdk.com Sanyo 619-661-6835 619-661-1055 www.sanyovideo.com Sumida 708-956-0666 708-956-0702 www.sumida.com Note: Please indicate that you are using the MAX1993 when contacting these component suppliers. Required Equipment • 7V to 24V, power supply, battery, or notebook AC adapter • DC bias power supply, 5V at 100mA • Dummy load capable of sinking 4A Table 1. Jumper JU1 Functions (Shutdown Mode) JU1 SHDN PIN 1 and 2 (default) Connected to VCC MAX1993 enabled 2 and 3 Connected to GND Shutdown mode Not installed SHDN must be driven by an external signal; connected to SHDN pad MAX1993 operation depends on the external SHDN signal levels • Digital multimeter (DMM) • 100MHz dual-trace oscilloscope Quick Start 1) Ensure that the circuit is connected correctly to the supplies and dummy load prior to applying any power. 2) Verify that the shunts are across JU1 pins 1 and 2 (SHDN high), JU2 pins 1 and 2 (forced PWM), JU3 pins 2 and 3 (1.5V output), and JU4 pins 1 and 2 (OVP/UVP enabled). 3) Turn on battery power prior to +5V bias power; otherwise, the output UVLO timer times out and the FAULT latch is set, disabling the regulator until +5V power is cycled or shutdown is toggled. 4) Observe the 1.5V output with the DMM and/or oscilloscope. Look at the LX switching node and MOSFET gate-drive signals while varying the load current. Detailed Description Jumper Settings Evaluating Other Dynamic Output Voltages The EV kit output is preset to 1.0V/1.5V. However, the output voltage can also be adjusted between 0.7V and 2V (FB = OUT) by selecting R6, R7, and R8 values. The 2 MAX1993 OUTPUT Table 2. Jumper JU2 Functions (Low-Noise Mode) JU2 SKIP PIN OPERATIONAL MODE 1 and 2 (default) Connected to VCC Low-noise mode, forcedPWM operation 2 and 3 Connected to GND Normal operation; allows automatic PWM/PFM switchover for pulse skipping at light load, resulting in highest efficiency MAX1993 regulates FB to the voltage set at REFIN. By changing the voltage at REFIN, the MAX1993 can be used in applications that require dynamic output-voltage changes between two set points. Using the GATE signal and open-drain output (OD), a resistor can be switched in and out of the REFIN resistor-divider, changing the voltage at REFIN. A logic high on GATE turns on the internal N-channel MOSFET, forcing OD to a low-impedance state. A low logic on GATE disables the N-channel MOSFET, so OD is high impedance. The _______________________________________________________________________________________ MAX1993 Evaluation Kit JU3 GATE PIN 1 and 2 MAX1993 OUTPUT Connected to VCC 2 and 3 (default) Connected to GND Not installed A logic high on GATE turns on the internal MOSFET, pulling OD to ground, VOUT = 1.0V. A logic low on GATE turns off the internal MOSFET so that OD appears as a high impedance, VOUT = 1.5V. GATE must be driven by an VOUT depends on the external signal; external GATE signal connected to GATE levels. pad Table 5. Jumper JU5 Functions (Switching-Frequency Selection) JU5 TON PIN 1 and 2 Connected to VCC FREQUENCY (kHz) 200 1 and 3 Connected to REF 450 1 and 4 Connected to GND 600 Not installed (default) Floating 300 (as shipped) Note: Do not change the operating frequency without first recalculating component values, because the frequency has a significant effect on preferred inductor value, peak current-limit level, MOSFET heating, PFM/PWM switchover point, output noise, efficiency, and other critical parameters. Refer to the MAX1993 data sheet for selection of output capacitor and inductor values for output voltages greater than 2V. Evaluating the MAX1992 Table 4. Jumper JU4 Functions (Overvoltage/Undervoltage Protection Selection) JU4 OVP/DISCHARGE MODE OVP/UVP PIN UVP 1 and 2 (default) Connected to VCC UVP is enabled; UVP threshold is 70% of nominal. 1 and 3 Connected to REF UVP is enabled. OVP and discharge mode are disabled. 1 and 4 Connected to GND UVP is disabled. OVP and discharge mode are disabled. Not installed Floating UVP is disabled. OVP and discharge mode are enabled. OVP is enabled; OVP threshold is 116% of nominal. Note: The MAX1993 detects and latches the discharge mode state set by OVP/UVP on startup. This EV kit can also be used to evaluate the MAX1992 by following these steps: 1) Remove the MAX1993 and install the MAX1992. 2) Short pin 21 (AGND) to pin 20 (PGND) at the IC pins. 3) Remove the shunt from JU3 (GATE open). 4) Install resistors R1 and R2 for the desired output voltage. The MAX1992 provides a fixed 1.8V output when FB is connected to VCC (R3 = short, R1 and R2 = open) or a fixed 2.5V output when FB is connected to GND (R2 = short, R1 and R3 = open). The output voltage can also be adjusted from 0.7V to 5.5V using a resistive voltage-divider formed by R1 and R2. The MAX1992 regulates FB to a fixed reference voltage (0.7V). The adjusted output voltage is: VOUT = VFB (1 + R1/R2) where VFB = 0.7V. Refer to the MAX1992 data sheet for selection of output capacitor and inductor values for different output voltages. two output voltages (FB = OUT) are determined by the following equations: VOUT(LOW) = VREF (R7/(R6 + R7)) VOUT(HIGH) = VREF (R7 + R8)/(R6 + R7 + R8) where VREF = 2.0V. _______________________________________________________________________________________ 3 Evaluates: MAX1992/MAX1993 Table 3. Jumper JU3 Functions (GATE— MAX1993 Only) Evaluates: MAX1992/MAX1993 MAX1993 Evaluation Kit C7 1µF 10V VCC VDD VBIAS +5V R10 20Ω REF R13 OPEN R20 R14 OPEN OPEN R9 100kΩ 22 19 VCC 3 PGOOD 4 VCC VDD LSAT BST V+ PGOOD 17 R19 SHORT (PC TRACE) 1 2 VCC 1 2 SKIP JU1 23 SHDN 3 MAX1993 13 SKIP (MAX1992) JU2 REF 3 DH U1 VCC 14 N1-B 4 15 REF JU5 2 3 R6 75kΩ 1% C8 1000pF 4 1 FLOAT = 300kHz DL 1.0V/1.5 AT 4A VOUT C2 270µF 2.5V 8 D1 7 8 REFIN (N.C.) OD (N.C.) (PGND) GND CSP 20 R11 0Ω 11 VCC GATE 1 2 C10 OPEN JU3 21 REF 3 GATE (AGND) CSN 12 R12 0Ω VCC R15 OPEN R21 R16 OPEN OPEN 2 FBLANK (N.C.) OUT R22 0Ω 10 VCC C12 OPEN C6 0.22µF 6 VCC C5 470pF R1 0Ω REF R4 100kΩ 1% REF FB R2 OPEN VCC 5 R5 49.9kΩ 1% ILIM OVP/UVP R3 OPEN 9 R17 OPEN 24 2 1 JU4 4 3 C11 OPEN REF Figure 1. MAX1993 EV Kit Schematic 4 C9 10µF 6.3V GND 1 600kHz R7 75kΩ 1% R8 150kΩ 1% TON N1-A 2 18 R18 0.015Ω 1% L1 2.5µH 16 200kHz 1 GND 3 7 450kHz C1 10µF 25V 6 C4 0.1µF LX GND VIN 7V TO 24V 5 SHDN C3 1µF 10V D2 CMPSH-3 _______________________________________________________________________________________ MAX1993 Evaluation Kit Figure 3. MAX1993 EV Kit PC Board Layout—Component Side Figure 4. MAX1993 EV Kit PC Board Layout—GND Layer 2 Figure 5. MAX1993 EV Kit PC Board Layout—GND Layer 3 _______________________________________________________________________________________ 5 Evaluates: MAX1992/MAX1993 Figure 2. MAX1993 EV Kit Component Placement Guide— Component Side Evaluates: MAX1992/MAX1993 MAX1993 Evaluation Kit Figure 6. MAX1993 EV Kit PC Board Layout—Solder Side Figure 7. MAX1993 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. 6 _____________________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.