MAX8627EVKIT

19-0687; Rev 0; 11/06 MAX8627 Evaluation Kit The MAX8627 evaluation kit (EV kit) is a fully assembled and tested circuit for evaluating the MAX8627 step-up converter. The MAX8627 EV kit operates from a 1.8V to 5.5V supply, and provides up to 1A output current from its 5V output. The output voltage can be adjusted from 3V to 5V by changing a resistor on the board. Features
1MHz PWM Switching Frequency
True Shutdown™ Output
Up to 95% Efficiency
1.0A Guaranteed Output Current at VIN ≥ 3V
Fast Soft-Start Eliminates Inrush Current Component List DESIGNATION QTY DESCRIPTION C1–C4 4 22µF ±20%, 6.3V X5R ceramic capacitors (1206) TDK C3216X5R0J226M JU1 1 3-pin header L1 1 1µH inductor TOKO A918CY-1R0M (D62LCB) R1 1 2MΩ ±1% resistor (0402) R2 1 499kΩ ±1% resistor (0402) R3 0 Not installed, (0402) PCB short resistor R4 0 Not installed, (0402) resistor U1 1 MAX8627ETD (14-pin TDFN, 3mm x 3mm) — 1 Shunt, 2 position — 1 MAX8627 EV kit PCB Quick Start Recommended Equipment • • 1.8V to 5.5V power supply capable of delivering 3A Voltmeter • Load (up to 1A) Procedure Follow the steps below to verify board operation. 1) Place the shunt across pins 2-3 of JU1 on the EV kit to enable the converter.
20µA (typ) Quiescent Current
0.1µA Logic-Controlled Shutdown
Tiny 14-Pin, 3mm x 3mm TDFN IC Package
Fully Assembled and Tested Ordering Information PART TEMP RANGE IC PACKAGE MAX8627EVKIT 0°C to +70°C 14 TDFN (3mm x 3mm) 3) Connect the positive power-supply lead to the EV kit pad labeled BATT. Connect the power-supply ground to the EV kit pad labeled GND (located next to BATT). 4) Connect the load between the EV kit pads labeled OUT and GND. 5) Turn on the power supply. 6) Connect the voltmeter across the EV kit pads labeled OUT and GND to verify that the output voltage is 5V. 2) Set the power-supply voltage between 1.8V and 5.5V. Turn off the power supply. Do not turn on the power supply until all connections are completed. True Shutdown is a trademark of Maxim Integrated Products, Inc. ________________________________________________________________ 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: MAX8627 General Description Evaluates: MAX8627 MAX8627 Evaluation Kit resistor R1. Find the value of R1 from the following equation: ⎛V ⎞ R1 = R2 x ⎜ OUT − 1⎟ ⎝ VFB ⎠ Table 1. JU1 Functions SHUNT POSITION FUNCTION 1-2 Shutdown 2-3 Enable Enable function is driven externally by a logic signal connected to the ON pad of the EV kit. Open where the lower feedback resistor, R2, is 499kΩ, and VFB is 1.01V. Adjusting the Current Limit The MAX8627 EV kit’s current limit is set to the default of 3.5A. To set the current limit lower, cut the PCB trace shorting R3, and then install resistors R3 and R4. Refer to the MAX8627 data sheet for information on calculating these resistor values. Detailed Description Adjusting the Output Voltage The default output voltage of the MAX8627 EV kit is 5V, but it can be adjusted between 3V and 5V by changing BATT 1.8V TO 5V C2 22µF GND C1 22µF 4, 5 L1 1µH LX 8, 9 BATT LX POUT ON OUT 5V 3 2 1 JU1 3 ON U1 POUT 6, 7 C4 22µF POUT 12 ILIM MAX8627 AGND OUTS 14 R4 OPEN 13 ILIM FB GND PG C3 22µF 2 R3 SHORT 1 R1 2MΩ 10, 11 R2 499kΩ GND Figure 1. MAX8627 EV Kit Schematic 2 _______________________________________________________________________________________ MAX8627 Evaluation Kit Evaluates: MAX8627 Figure 2. MAX8627 EV Kit Component Placement Guide—Component Side Figure 3. MAX8627 EV Kit PCB Layout—Component Side Figure 4. MAX8627 EV Kit PCB 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 3 © 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.