Evaluates: MAX9940 19-4520 Rev 0 3/09 MAX9940 Evaluation Kit General Description Features The MAX9940 evaluation kit (EV kit) is an assembled Output Connection to 1-Wire Device (DS2413) and tested PCB used to evaluate the MAX9940 high- Pushbutton that Initiates High-Voltage Fault voltage signal-line protector for microcontroller ports. Lead(Pb)-Free and RoHS Compliant The MAX9940 EV kit demonstrates that microcontroller ports are protected against high-voltage faults. Proven PCB Layout The EV kit comes with a MAX9940AXK+ installed. Fully Assembled and Tested Ordering Information PART TYPE MAX9940EVKIT+ EV Kit +Denotes lead(Pb)-free and RoHS compliant. Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION 10F 10%, 16V X5R ceramic R2, R3 2 220 5% resistors (0603) capacitors (0805) C1, C7, C9 3 R4 1 3k 5% resistor (0603) KEMET C0805C106K4PACTU R5 0 Not installed, resistor (0603) 0.1F 10%, 16V X7R ceramic SW1, SW2, SW3 3 Pushbutton switches C2, C3, C4 3 capacitors (0603) High-voltage signal-line protector TDK C1608X7R1C104K U1 1 (5 SC70) 1F 10%, 16V X5R ceramic Maxim MAX9940AXK+ C8 1 capacitor (0603) Microcontroller (68 QFN-EP*) TDK C1608X5R1C105K U2 1 Maxim MAXQ2000-RAX+ 10pF 5%, 50V C0G ceramic C5, C6 2 capacitors (0603) LDO regulator (5 SC70) U3 1 Murata GRM1885C1H100J Maxim MAX8511EXK25+ D1 1 Green LED (0603) Addressable switch (6 TSOC) U4 1 Maxim DS2413P+ D2, D3, D4 3 Red LEDs (0603) Not installed, Schottky diode 16MHz crystal (3 SOT23) D5 0 Y1 1 Hong Kong Xtals Fairchild BAT54C SSM1600000E18FAF Not installed, 2 x 5-pin JTAG 1 Shunt H1 0 header 1 PCB: MAX9940 Evaluation Kit+ JU1 1 3-pin header *EP = Exposed pad. R1 1 2k 5% resistor (0603) Component Suppliers SUPPLIER PHONE WEBSITE Hong Kong Xtals Ltd. 852-35112388 www.hongkongcrystal.com KEMET Corp. 864-963-6300 www.kemet.com Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com TDK Corp. 847-803-6100 www.component.tdk.com Note: Indicate that you are using the MAX9940 when contacting these component suppliers. 1-Wire is a registered trademark of Maxim Integrated Products, Inc. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX9940 Evaluation Kit Quick Start Detailed Description of Hardware The MAX9940 EV kit is an assembled and tested PCB Recommended Equipment used to evaluate the MAX9940 high-voltage signal-line 3.3V DC power supply protector for microcontroller ports. The MAX9940 EV kit 28V DC power supply demonstrates that microcontroller ports are protected against high-voltage faults. Procedure The MAX9940 EV kit is fully assembled and tested. START Pushbutton Follow the steps below to verify board operation. Press the START pushbutton (SW2) to start communicat- Caution: Do not turn on power supplies until all ing with the DS2413, dual-channel addressable switch. connections are completed. The on-board microcontroller commands the DS2413 to 1) Connect the 3.3V DC power supply to the VCC and continuously blink the green LED for 30 cycles. GND pads on the EV kit. STOP Pushbutton 2) Connect the 28V DC power supply to the FAULT Press the STOP pushbutton (SW3) to stop communicat- and GND pads on the EV kit. ing with the DS2413. The green LED should stop blink- 3) Verify that a shunt is installed in the 1-2 position on ing if the STOP pushbutton is pressed. If JU1 is in the jumper JU1. 2-3 position, then the MAX9940 is also disabled. 4) Turn on both supplies. FAULT Pushbutton 5) Press the START pushbutton (SW2) momentarily Press the FAULT pushbutton (SW1) while the microcon- and observe as the green LED (D1) continuously troller is communicating with the DS2413. The red LEDs turns on and off every 500ms for 30 cycles. indicate that a voltage is applied to the EXT pin of the MAX9940. 6) While the green LED is still blinking, press the FAULT pushbutton (SW1) and observe as the red The absolute maximum voltage of the DATA signal of the LEDs (D2, D3, and D4) turn on. Once SW1 is deac- microcontroller (U2) is specified to be (V + 0.5)V, DDIO tivated, the red LEDs turn off and the green LED i.e., 3.8V. continues blinking until it reaches the end of its When the MAX9940 detects a voltage greater than sequence. (V + 0.3)V, it automatically turns off, presenting the CC high voltage fault signal on its EXT pin from appearing on the DATA signal line, thus protecting the microcon- troller from damage. Table 1. VCC Selection (JU1) SHUNT DESCRIPTION POSITION 1-2* Connects the MAX9940 to the +3.3V supply. Before changing shunt positions, press the STOP pushbutton (SW3). Enables the MAX9940 using the MAXQ2000s GPIO pin, which is used for power saving. Power is only applied when the START pushbutton (SW2) is pressed. Power is disabled when the MAXQ2000 is done communicating with the 2-3 DS2413. Before changing shunt positions, press the STOP pushbutton (SW3). Note: The MAX9940 can withstand fault voltages even when its V = 0. CC *Default position. 2 Evaluates: MAX9940