Evaluates: MAX14852/MAX14854/ MAX148X1 Evaluation Kit MAX14856/MAX14858 Startup Procedure General Description The EV kit is fully assembled and tested. Follow the steps The MAX148X1 evaluation kit (EV kit) is a fully assembled below to verify board operation. and tested PCB that demonstrates the functionality of the MAX14852 isolated RS-485/RS-422 transceiver. The EV 1) Set the DC power supply to 3.3V and connect the kit operates from a single 3.3V supply and features an on- DC power supply between the EV kits V and DDA board isolated power supply to power the secondary-side GNDA connectors. of the circuit. 2) Ensure that all jumpers are in their default positions (see Table 1). The MAX148X1 EV kit may also be used to evaluate the 3) Turn on the power supply. MAX14854, MAX14856, and the MAX14858. 4) Set the signal/function generator to output a 100kHz 0-to-3V square wave. NOTE: Set the signal/function Features generator to operate with a high-impedance load. If Operates From a Single 3.3V Supply needed, the R1 pad is available to add a 50 impedance Terminal Block Connectors for Easy RS-485/RS-422 to ground. Evaluation 5) Connect the signal/function generator to the TXD Up to 5000V Isolation for 60s test point. RMS 6) Using the oscilloscope, verify that the Y and Z outputs Fully Assembled and Tested switch as the signal toggles. Quick Start Required Equipment MAX148X1 EV kit 3.3V, 1A DC power supply Signal/function generator Oscilloscope Ordering Information appears at end of data sheet. 19-8594 Rev 0 7/16Evaluates: MAX14852/MAX14854/ MAX148X1 Evaluation Kit MAX14856/MAX14858 Resistors R2 R4 Configuration Detailed Description of Hardware For end-of-the-line transceivers, close J9 to connect The EV kit is a fully assembled and tested circuit board a 120 termination resistor (R6) between the A and B for evaluating the MAX14852 isolated RS-485/RS-422 RS-485 receiver inputs on the MAX14852. transceiver (U2). The EV kit has been designed to allow for evaluating the MAX14852 alone or in a standard Close J6 to connect a 120 termination resistor (R3) RS-485 configuration. The EV kit is powered from a single between the Y and Z driver outputs. 3.3V power supply. Pullup and pulldown resistors are generally used on the receiver inputs to guarantee a known state in the event Powering the Board that all nodes on the bus are in receive mode, or the The power on the EV kit is derived from a single 3.3V cable becomes disconnected. The exact value for these source. Connect an external supply from GNDA to either resistors will vary with the application. R2 and R4 pads are the V test point or P1 connector to supply the 3.3V to DDA provided for pullup and pulldown resistors on the Y and the logic-side (A) of the circuit. Z lines. R5 and R7 pads provide for pullup and pulldown An on-board MAX258 transformer driver (U1) and external resistors on the A and B lines, if needed. The use of transformer (TX1) generate an isolated supply for powering any of these resistors is purely optional. Note that the the (B) isolated side of the board. To disable the MAX258 MAX14852 features true fail-safe receiver inputs, which circuit, connect jumper J1 to 2-3. To disconnect the output ensures that RXD is high when the receiver inputs are of the transformer circuit from the MAX14852 LDO input, shorted, open, or connected to an idle bus. remove the shunt on J5. Evaluating the Isolated RS-485 Interface Driver and Receiver Enable Selection The EV kit features three jumpers (J2, J3, and J4) to enable/disable the driver and receiver outputs. Set J2 to 2-3 to enable the receiver. Set J3 to 1-2 to enable the driver. To actively control both enables, remove J2 and J3 and close J4, which connects DE and RE together. Loopback Configuration The MAX14852 features one drive channel and one receive channel. Driver outputs are Y and Z and receiver inputs are A and B. To configure the device for loopback testing, close J7 and J8 to connect B to Z and A to Y, respectively. Maxim Integrated 2 www.maximintegrated.com