MAX14781E Half-Duplex RS-485 Transceiver with Polarity Correction General Description Benefits and Features The MAX14781E +5V, half-duplex 25kV ESD-protected Automatic Polarity Correction RS-485 transceiver features integrated automatic polar- Integrated Protection Increases Robustness ity correction to ensure that miswired A and B lines are High ESD Protection autonomously corrected, simplifying equipment and net- 25kV HBM ESD work installation. 15kV IEC 61000-4-2 Air Gap Discharge ESD The MAX14781E includes slew-rate limited drivers that 9kV IEC 61000-4-2 Contact Discharge ESD minimize EMI, allowing for error-free data transmission True Fail-Safe Receiver up to 370kbps. Hot-Swap Functionality This device includes fail-safe circuitry, guaranteeing a +5V Operation logic-high receiver output when the receiver inputs are shorted or open. Hot-swap functionality on the receiver Low 10A (max) Shutdown Current and driver enable inputs also eliminates false transitions Extended -40C to +85C Operating Temperature on the bus during power-up or live insertion. The MAX14781E features a 1/8-unit load receiver input impedance, allowing up to 256 transceivers on the bus. All driver outputs are protected up to 25kV ESD using the Ordering Information appears at end of data sheet. Human Body Model. The MAX14781E is available in an 8-pin SO package and operates over the extended -40C to +85C temperature range. For related parts and recommended products to use with this part, refer to www.maximintegrated.com/MAX14781E.related. Applications Power Meter Networks HVAC Networks Control Systems Functional Diagram MAX14781E RO A R RE POLARITY CORRECT DE B DI D 19-6859 Rev 0 12/13MAX14781E Half-Duplex RS-485 Transceiver with Polarity Correction Absolute Maximum Ratings (All voltages referenced to GND) Operating Temperature Range ............................-40C to +85C V .......................................................................-0.3V to +6.0V Junction Temperature ......................................................+150C CC RE, RO ..................................................... -0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +150C CC DE, DI ..................................................................-0.3V to +6.0V Lead Temperature (soldering 10 sec) .............................+300C A, B ........................................................................-8.0V to +13V Soldering Temperature (reflow) .......................................+260C Short-Circuit Duration (RO, A, B) to GND .................Continuous Continuous Power Dissipation (T = +70C) A 8-Pin SO (derate at 7.6mW/C above +70C) ..............606mW Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. (Note 1) Package Thermal Characteristics Junction-to-Ambient Thermal Resistance ( ) ............132C/W Junction-to-Case Thermal Resistance ( ) ...................38C/W JA JC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. Electrical Characteristics (V = 5V 10%, T = -40C to +85C, unless otherwise noted. Typical values are at V = 5V and T = +25C.)(Notes 2, 3) CC A CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DRIVER Supply Voltage V 4.5 5.5 V CC R = 100, Figure 1 3 V L CC Differential Driver Output V R = 54, Figure 1 2 V V OD L CC No load, Figure 1 V CC Change in Magnitude of V R = 100 or 54, Figure 1 0.2 V OD L Differential Output Voltage Driver Common-Mode Output V R = 100 or 54, Figure 1 (Note 4) V /2 3 V OC L CC Voltage Change in Magnitude of V R = 54, Figure 1 (Note 4) 0.2 V OC L Common-Mode Otput Voltage Input Voltage High V DE, DI, RE 3.0 V IH Input Voltage Low V DE, DI, RE 0.8 V IL Input Current I DE, RE -1 +1 A IN Input Impedance Until First Until the first DE/RE transition occurs, Transition at Power-Up (DE, R 3.65 8.8 k FTPU Figure 9 (Note 7) RE) Input Impedance Until First Until the first DE/RE transition occurs, Transition After POR Delay (DE, R 7 60 k FTPOR Figure 9 RE) Output low, 0V +40 +250 V 12V OUT Driver Short-Circuit Output Driver is in short I mA OSD Current circuit (Note 5) Output high, -7V -250 -40 V V OUT CC Maxim Integrated 2 www.maximintegrated.com