Click here to ask about the production status of specific part numbers. Evaluates: MAX33072E MAX33072E Shield Evaluation Kit General Description Features and Benefits The MAX33072E Shield evaluation kit (EV kit) is a fully Easy Evaluation of the MAX33072E assembled and tested printed circuit board (PCB) that I/O Interface Compatibility from 1.71V to 5.5V demonstrates the functionality of the MAX33072E half- Proven PCB Layout duplex RS-485 transceiver, with 65V fault protection, extended 40V common-mode range, and 40kV ESD Mbed/Arduino Platform Compatible Human Body Model (HBM) for A,B data lines. The EV kit Fully Assembled and Tested features a digital isolator, which is used as a level trans- lator between the RS-485 transceiver and the controller Ordering Information appears at end of data sheet. interface. EV Kit Photo with Jumpers and Test Point Positions 319-100551 Rev 0 6/20Evaluates: MAX33072E MAX33072E Shield Evaluation Kit If external protection is desired beyond the devices built- Quick Start in protection, the EV kit also features footprints for TVS Required Equipment diodes (D1 and D2) that can be connected to the A and B MAX33072E Shield EV kit lines using JU7 and JU9, respectively. 3.3V (or 5V), 500mA DC power supply Powering the Board Signal/function generator that can generate a The MAX33072E Shield EV kit requires two power sup- 250kHz square-wave signal plies: one 3V to 5.5V supply for the MAX33072E (U1) Oscilloscope transceiver applied at the VCC EXT test point, and one 1.71V to 5.5V supply for the microcontroller domain Procedure applied at the IOREF test point. When the EV kit board is The EV kit is fully assembled and tested. Use the follow- used with an Arduino/Mbed board, the power supply for ing steps to verify board operation: U1 can also come from the Arduino/Mbed boards 3.3V 1) Place the MAX33072E Shield EV kit on a noncon- or 5V rail. Place the shunt on the 2-3 position of JU1 to ductive surface to ensure that nothing on the PCB connect VCC to the VDD EXT pin. Place the shunt of JU1 gets shorted to the workspace. on the 1-2 position or 1-4 position to connect the VCC of U1 to the Arduino/Mbed 3.3V or 5V supply rail. In this 2) Set JU2 to the 1-2 position (DE = 1) and JU3 to the scenario, IOREF is directly taken from the Arduino/Mbed 1-4 position (POL = 0). Set all other jumpers to their header. default position as shown in Table 1. 3) With +3.3V (or 5V) power supply disabled, connect On-Board Termination the positive terminal to the VCC EXT and IOREF A properly terminated RS-485 bus is terminated at each test points. Connect the negative terminal to a GND end with the characteristic impedance of the cable. For test point. CAT5 or CAT6 cables, this is typically 120 on each end 4) Connect the positive terminal of the function genera- for a 60 load on the RS-485 driver. The MAX33072E tor to D0 (pin 1 of J4) and negative terminal to any Shield EV kit features a selectable 60 or 120 load GND test points on the shield. circuit between the A and B driver outputs. If the board 5) Set the function generator to output a 250kHz square is evaluated in a system and is connected at the end of wave between 0V and 3.3V (or 5V), and then enable the cable, then select the 120 termination. The termina- function generator output. tion resistors on the MAX33072E Shield EV kit should be changed to 60 with a 100pF load, to simulate a com- 6) Turn on the +3.3V (or 5V) DC power supply. plete system load during evaluation. 7) Connect an oscilloscope probe on D1 (pin 2 of J4) and verify that the D1 output signal (RO) matches DI and RO Configuration the D0 input signal (DI). The digital channels for DI and RO are select- ed through JU8. It consists of three columns and Detailed Description of Hardware 16 rows. The columns labeled DI and RO are con- The MAX33072E Shield EV kit is a fully assembled and nected to the MAX33072E through the digital isolator tested circuit board for evaluating the MAX33072E fault- (MAX14931FASE+ (U2)). The middle column is the digi- protected half-duplex RS-485 transceiver (U1) with 65V of tal I/O pins, D0 to D15, from the Arduino/Mbed header. fault protection. The EV kit is designed to evaluate the This provides flexibility for the user to select different MAX33072E alone or in a RS-485 system. The MAX33073E resources on the microcontroller to transmit and receive Shield EV kit enables an Mbed or Arduino platform to signals to and from the RS-485 transceiver. Table 2 communicate on a RS-485 bus. The MAX14931 digital iso- shows the list of JU8 jumper options. lator is used as a level translator with a 1.71V to 5.5V sup- ply range. Remove the 0 resistor R6 to apply the trans- mitter input signal directly on the DI test point. Likewise, remove the 0 resistor R3 to measure the receiver output signal directly on the RO test point. Arduino is a registered trademark of Arduino, LLC. Mbed is a registered trademark of Arm Limited. Maxim Integrated 2 www.maximintegrated.com