Evaluates: MAX13487E/MAX13488E 19-3204 Rev 1 11/08 MAX13487E Evaluation Kit General Description Features The MAX13487E evaluation kit (EV kit) is a fully assem- Demonstrates MAX13487E AutoDirection Feature bled and tested PCB that contains a half-duplex RS- Designed for 2500V Isolation RMS 485/RS-422 AutoDirection-controlled transceiver with ESD protection. The EV kit circuit features a differential 1/4 RS-485 Unit Loading driver and receiver. The circuits receiver is a 1/4-unit 500kbps Half-Duplex RS-485/RS-422 load for the RS-485 bus and can communicate up to Communication 500kbps. The MAX13487E AutoDirection and reduced- driver slew-rate features are demonstrated on the EV kit +5V DC Input Range circuit. The EV kit can also be used to evaluate the Isolated +5V Output MAX13488E IC, which can communicate up to 16Mbps. Center-Tapped Full-Wave Rectifier Output Power for the transceiver circuit is provided by a MAX256 H-bridge DC/DC converter, which powers the isolated 420kHz Switching Frequency section of the MAX13487E RS-485/RS-422 circuit. Input- Output Current Limit and Thermal Shutdown ripple current and radiated noise are minimized by using an H-bridge design. The isolated H-bridge DC-DC con- Low-Cost Integrated-FET H-Bridge Design verter operates at 420kHz. Input power to the EV kit Also Evaluates MAX13488E (After IC circuit can be supplied by a +5V DC source. Replacement) The DC-DC converter circuit uses a surface-mount transformer to provide galvanic isolation and a full-wave Fully Assembled and Tested rectifier, and provides a regulated +5V to the MAX13487E. A MAX1659 linear low dropout (LDO) reg- Ordering Information ulator provides the regulated output and up to 300mA of current. The output current limit and thermal shut- PART TYPE down provide for a robust isolated RS-485/RS-422 MAX13487EEVKIT EV Kit transceiver circuit and power supply. The transceiver Denotes RoHS compliant. and power circuits and PCB are designed for 2500V isolation. RMS Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION 10F 10%, 10V X7R ceramic JU1, JU3, JU4, 5 2-pin headers C1 1 capacitor (1206) JU5, JU6 Murata GRM31CR71A106K JU2 1 3-pin header 0.47F 10%, 16V X7R ceramic R1 1 39.2k 1% resistor (0603) C2 1 capacitor (0805) R2, R9 2 100k 5% resistors (0603) Murata GRM219R71C474K R4, R5 2 270 5% resistors (0805) 0.1F 10%, 16V X7R ceramic R6, R8 2 220 5% resistors (0805) C3, C5, C6, C7 4 capacitors (0603) R7 1 120 5% resistor (0805) Murata GRM188R71C104K 500H, 1.5W, 3:8-turn, 400kHz 1F 10%, 16V X7R ceramic T1 1 transformer (6-pin Gull Wing) C4 1 capacitor (0805) HALO Electronics TGM-380NARL Murata GRM21BR71C105K Half-duplex, high-speed transceiver 30V, 1A Schottky diodes (SOD123) D1, D2 2 U1 1 (8 SO) Diodes Inc. B130LAW Maxim MAX13487EESA+ 15V, 350mW 5% zener diode D3 1 (SOT-23) C entral S em i conduc tor C M P Z 5245B+ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX13487E Evaluation Kit Component List (continued) Component Suppliers SUPPLIER PHONE WEBSITE DESIGNATION QTY DESCRIPTION CEL/NEC Integrated primary-side controller ( C ali forni a E as tern 408-588-2247 www.cel.com and H-bridge driver (8 SO-EP*) U2 1 Lab or atori es/NE C ) Maxim MAX256ASA+ Linear regulator (8 SO) Central U3 1 Semiconductor 631-435-1110 www.centralsemi.com Maxim MAX1659ESA+ Corp. 15Mbps CMOS photocouplers Diodes, Inc. 805-446-4800 www.diodes.com U4, U5 2 (5 SO) HALO Electronics, CEL/NEC PS9151-A 650-903-3800 www.haloelectronics.com Inc. 6 Shunts (JU1JU6) Murata www.murata- 4 Rubber bumpers Electronics North 770-436-1300 northamerica.com 1 PCB: MAX13487E Evaluation Kit America, Inc. *EP = Exposed pad. Note: Indicate that you are using the MAX13487E or MAX13488E when contacting these component suppliers. Note: The +5V supply powering the MAX13487E EV kit Quick Start must be current-limited at 550mA and the output load Required Equipment current for the output should be limited to less than Before beginning, the following equipment is needed: 300mA. One +5V 550mA current-limited power supply with Detailed Description of Hardware a built-in current meter The EV kit features a MAX13487E IC in an 8-pin SO sur- One voltmeter face-mount package and demonstrates the ESD- One logic signal generator protected MAX13487E RS-485/RS-422 AutoDirection transceiver. The differential driver and receiver are con- One oscilloscope with a differential probe figured for half-duplex operation and communicate up Procedure to 500kbps. The transceiver circuit is a 1/4-unit load on The MAX13487E EV kit is fully assembled and tested. the receivers bus. Follow the steps below to verify board operation. The EV kit features PCB pads to ease interfacing with Caution: Do not turn on the power supply until all the driver/receiver logic signals on the non-isolated side connections are completed. using the TXD, RXD, and PGND pads, respectively. The 1) Connect a voltmeter to the VOUT and GND PC pads. MAX13487E IC is powered from the isolated VOUT supply. Photocoupler U4 provides isolation for the 2) Verify that a shunt is not installed across the pins of receivers RO signal (RXD pad) and U5 provides isola- jumper JU1 (U2 enabled). tion for the data-in DI signal (TXD pad). 3) Verify that a shunt is installed across pins 1-2 of The EV kit demonstrates the MAX13487E slew-rate jumper JU2 (U1 enabled). limited driver, which minimizes EMI radiation. 4) Verify that a shunt is installed across the pins of Photocouplers U4 and U5 are rated for up to 15Mbps. jumpers JU3 (AutoDirection enabled), JU4 (pull- The MAX13487E receiver signal is provided at the RO down), JU6 (pullup), and JU5 (bus terminated). pin. The RO pin will give a logic-high if A-B > +200mV. 5) Connect the +5V power supply to the VIN pad. A logic-low is given if A-B < -200mV. Refer to the Connect the power supplys ground to the PGND pad. Transmitting and Receiving sections in the Function 6) Turn on the power supply and verify that the volt- Tables in the MAX13487E/MAX13488E IC data sheet meter at VOUT reads +5V. for additional information on the AutoDirection circuitry operation. Also see the AutoDirection and Receiver 7) Using the logic signal generator, apply a +5V logic Enable Selection section in this document for configur- signal to the TXD PCB pad and PGND. ing the AutoDirection and receiver operation. 8) Using the oscilloscope and differential probes, verify the signal at the A-B pads (isolated side). 2 Evaluates: MAX13487E/MAX13488E