Evaluates: MAX8643 19-0642 Rev 0 10/06 MAX8643 Evaluation Kit General Description Features The MAX8643 evaluation kit (EV kit) is a fully assembled Internal 37m On-Resistance MOSFETs and tested PCB that demonstrates the capabilities of 3A Output PWM Step-Down Regulator the MAX8643 integrated 3A step-down regulator. The EV kit generates a +1.8V output voltage at load cur- 1% Output Accuracy over Load, Line, and rents up to 3A from a 2.35V to 3.6V input voltage range. Temperature The MAX8643 switches at 1MHz and up to 95% effi- Operates from 2.35V to 3.6V Input Supply ciency with the supplied components. Adjustable Output from 0.6V to (0.9 x V ) IN 500kHz to 2MHz Adjustable Frequency Component List Allows All-Ceramic Capacitor Design Programmable Soft-Start Time DESIGNATION QTY DESCRIPTION 24-Pin, 4mm x 4mm Thin QFN Package 22F 10%, 6.3V X5R ceramic C1, C2 2 capacitors (0805) REFIN for DDR Termination and Tracking TDK C2012X5R0J226K Applications 0.1F 10%, 25V X7R ceramic Surface-Mount Components C3, C9 2 capacitors (0603) Assembled and Tested TDK C1608X7R1E104K 0.01F 10%, 50V X7R ceramic C4, C6 2 capacitors (0603) Ordering Information TDK C1608X7R1H103K PART TEMP RANGE IC PACKAGE 1F 10%, 16V X5R ceramic MAX8643EVKIT+ 0C to +70C 24 TQFN (4mm x 4mm) C5 1 capacitor (0603) TDK C1608X5R1C105K +Denotes a lead-free and RoHS-compliant EV kit. Not installed, ceramic capacitors C7, C13, C14 0 (0603) Quick Start 0.022F 10%, 50V X7R ceramic capacitor (0603) C8 1 Recommended Equipment TDK C1608X7R1H223K 2V to 4V at +3A variable DC power supply or battery 560pF 10%, 50V X7R ceramic Digital multimeter (DMM) C10 1 capacitor (0603) Up to 3A load TDK C1608X7R1H561K Ammeter (optional) 1500pF 10%, 50V X7R ceramic Procedure C11 1 capacitor (0603) The MAX8643 EV kit is fully assembled and tested. TDK C1608X7R1H152K Follow the steps below to verify board operation. 33pF 5pF, 50V C0G ceramic 1) Preset the DC power supply to 3.3V. Turn off the C12 1 capacitor (0603) power supply. Caution: Do not turn on the power TDK C1608C0G1H330CT supply until all connections are made. 1000pF 10%, 50V X7R ceramic 2) Remove the shunt from JU1. C15 1 capacitor (0603) 3) Verify that no two pins are shunted together on TDK C1608X7R1H102K jumper JU3. Component List continued on next page. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX8643 Evaluation Kit 4) Verify that there is a shunt on pins 1-2 of jumper Component List (continued) JU4. DESIGNATION QTY DESCRIPTION 5) Connect the positive lead of the power supply to the JU1, JU2 2 2-pin headers IN pad and connect the negative lead of the power supply to the GND pad on the EV kit. JU3, JU4 2 3-pin headers 6) Connect the positive lead of the DMM to the OUT 0.47H, 7.6m , 9.6A inductor pad and connect the negative lead of the DMM to L1 1 (7.7mm x 7mm x 2mm) the GND pad on the EV kit. TOKO FDV0620-R47 7) Turn on the power supply. R1 1 10 5%, resistor (0603) lead free 8) Verify that the voltage at OUT is 1.8V. R2 1 10k 5% resistor (0603) lead free 9) Connect the load between OUT and GND. R3 1 1k 5%, resistor (0603) lead free 10) Verify that the voltage at OUT is 1.8V. 2.67k 1%, resistor (0603) lead R4 1 free Detailed Description R5 1 20k 5% resistor (0603) lead free Evaluating Other Output Voltages R6 1 158 1% resistor (0603) lead free The MAX8643 EV kit comes preset to a 1.8V output 49.9k 1% resistor (0603) lead voltage. As shown in Table 1, the output voltage is pin- R7 1 free programmable by the logic states of CTL1 and CTL2, jumpers JU3 and JU4, respectively. CTL1 and CTL2 Not installed, resistor (0603). Must are three-level inputs: V , unconnected, and GND. DD be 8.06k 1% resistor (0603) R8 0 The logic states of CTL1 and CTL2 should be pro- when populated for adjustable grammed only before power-up. To avoid damage to output voltage programming. the IC, CTL1 and CTL2 should not be changed once soft-start is complete. If the output voltage needs to be Not installed, resistor (0603) for reprogrammed, cycle power or EN and reprogram dur- R9 0 adjustable output voltage ing or before soft-start. programming R10 1 2.2 5% resistor (0603) lead free Table 1. CTL1 and CTL2 Output Voltage MAX8643ETG+ U1 1 Selection (24-pin, 4mm x 4mm TQFN) 5 Shunts CTL1/JU3 CTL2/JU4 V (V) OUT 1 MAX8643 EV kit PCB 0.6 or external 2-3 2-3 divider 1-2 1-2 0.7 Component Suppliers 2-3 Unconnected 0.8 2-3 1-2 1.0 SUPPLIER PHONE WEBSITE Unconnected 2-3 1.2 TDK 847-803-6100 www.component.tdk.com Unconnected Unconnected 1.5 TOKO 800-745-8656 www.toko.com Unconnected 1-2 1.8 Vishay 402-563-6866 www.vishay.com 1-2 2-3 2.0 Note: Indicate that you are using the MAX8643 when contacting 1-2 Unconnected 2.5 these component suppliers. When the output voltage of the MAX8643 is pro- grammed to a preset voltage, Ri is internal to the IC and R9 is not installed (Figure 1b). 2 Evaluates: MAX8643