EVALUATION KIT AVAILABLE MAX14938/MAX14939 2.75kV Isolated 20Mbps Half-Duplex PROFIBUS/ RMS RS-485 Transceivers with 35kV ESD Protection General Description Benefits and Features The MAX14938/MAX14939 isolated RS-485/PROFIBUS-DP High-Performance Transceiver Enables Flexible Designs transceivers provide 2750V (60s) of galvanic isolation Integrated LDO for Cable-Side Power RMS between the cable side (RS-485 driver/receiver side) and Compliant with RS-485 EIA/TIa-485 Standard 20Mbps Maximum Data Rate the UART side of the device. Isolation improves communication by breaking ground loops and reduces noise when there Allows Up to 128 Devices on the Bus are large differences in ground potential between ports. Integrated Protections Ensures Robust Communication These devices allow for robust communication up to 35kV ESD (HBM) on Driver Outputs/Receiver Inputs 20Mbps. 2.75kV Withstand Isolation Voltage for 60s (V ) RMS ISO 630V Maximum Repetitive Peak-Isolation An integrated LDO provides a simple and space-efficient PEAK architecture for providing power to the cable side of the Voltage (V ) IORM 445V Maximum Working-Isolation Voltage IC. RMS (V ) IOWM Each device includes one half-duplex driver/receiver > 30 Years Lifetime at Rated Working Voltage channel. The receiver is 1/4-unit load, allowing up to 128 Withstands 10kV Surge per IEC 61000-4-5 transceivers on a common bus. Thermal Shutdown Integrated true fail-safe circuitry ensures a logic-high on Safety Regulatory Approvals the receiver output when inputs are shorted or open. Undervoltage lockout disables the driver when cable-side UL According to UL1577 or UART-side power supplies are below functional levels. cUL According to CSA Bulletin 5A The driver outputs/receiver inputs are protected from Applications 35kV electrostatic discharge (ESD) to GNDB on the Industrial Automation Equipment cable side, as specified by the Human Body Model (HBM). Programmable Logic Controllers The MAX14938/MAX14939 are available in a wide-body HVAC 16-pin SOIC package and operate over the -40C to Power Meters +105C temperature range. Ordering Information appears at end of data sheet. Functional Diagram VDDA VLDO MAX14938 MAX14939 LDO VDDB (PV) + SBA RXD A RE TXD B DE (DEM) () MAX14938 only GNDA GNDB * MAX14939 only 19-8115 Rev 1 1/17 RS-485 TRANSCEIVERMAX14938/MAX14939 2.75kV Isolated 20Mbps Half-Duplex PROFIBUS/ RMS RS-485 Transceivers with 35kV ESD Protection Absolute Maximum Ratings V to GNDA ......................................................-0.3V to +6V Continuous Power Dissipation (T = +70C) DDA A V to GNDB .......................................................-0.3V to +6V 16-pin W SOIC (derate 14.1mW/C DDB V to GNDB .....................................................-0.3V to +16V above +70C) .........................................................1126.8mW LDO TXD, DE, RE, PV to GNDA ....................................-0.3V to +6V Operating Temperature Range ......................... -40C to +105C SBA, RXD to GNDA ............................. -0.3V to (V + 0.3V) Junction Temperature ......................................................+150C DDA DEM to GNDB ...................................... -0.3V to (V + 0.3V) Storage Temperature Range ............................ -65C to +150C DDB A, B to GNDB ...........................................................-8V to +13V Lead Temperature (soldering, 10s) .................................+300C Short Circuit Duration (RXD, SBA to GNDA, Soldering Temperature (reflow) .......................................+260C A, B, DEM ,V to GNDB)..................................Continuous DDB 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. Package Thermal Characteristics (Note 1) Junction-to-Ambient Thermal Resistance ( ) ..............71C/W Junction-to-Case Thermal Resistance ( ) ...................23C/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. DC Electrical Characteristics (V V = 1.71V to 5.5V, V V = 4.5V to 5.5V, T = T to T , unless otherwise noted. Typical values are DDA GNDA DDB GNDB A MIN MAX at V V = 3.3V, V V = 5V, V = V , and T = +25C.) (Notes 2, 3) DDA GNDA DDB GNDB GNDA GNDB A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER V 1.71 5.5 DDA Supply Voltage V V 4.5 5.5 DDB V = 5V, DE = high, RE = TXD = low, DDA I 4 6.6 DDA RXD unconnected, no load Supply Current mA DE = high, RE = TXD = low, RXD I 7.6 12.5 DDB unconnected, no bus load, V = 5V DDB V V rising 1.50 1.58 1.65 Undervoltage-Lockout UVLOA DDA V Threshold V V rising 2.55 2.7 2.85 UVLOB DDB V 50 Undervoltage-Lockout UVHYSTA mV Threshold Hysteresis V 200 UVHYSTB LDO LDO Supply Voltage V Relative to GNDB, LDO is on (Note 4) 4.68 14 V LDO DE = high, TXD = low, no bus load, LDO Supply Current I 7.7 12.9 mA LDO V = 5V LDO LDO Output Voltage V 4.5 5 5.5 V DDB LDO Current Limit 300 mA V = 5.68V, I = 20mA to LDO LOAD Load Regulation 0.19 1.7 mV/mA 40mA Line Regulation V = 5.68V to 14V, I = 20mA 0.12 4.5 mV/V LDO LOAD Maxim Integrated 2 www.maximintegrated.com