EVALUATION KIT AVAILABLE MAX14946 2.75kV Isolated 500kbps Half-Duplex RMS RS-485/RS-422 Transceiver with 30kV ESD Protection and Integrated Transformer Driver General Description Benefits and Features The MAX14946 isolated RS-485/RS-422 transceiver High Integration Simplifies Designs provides 2750V (60s) of galvanic isolation between Integrated LDO for Cable-Side Power RMS the cable side (RS-485/RS-422 driver/receiver side) and Integrated Transformer Driver for Power Transfer to Cable Side Has Up to 80% Efficiency at 150mA the UART side of the device. Isolation improves communication by breaking ground loops and reduces noise when there Load are large differences in ground potential between ports. High-Performance Transceiver Enables Flexible This device allows for robust communication up to 500kbps. Designs The device includes an integrated 450kHz transformer Compliant with RS-485 EIA/TIA-485 Standard 500kbps (max) Data Rate driver for power transfer to the cable side of the transceiver using an external transformer. An integrated LDO provides Up to 256 Devices on the Bus a simple and space-efficient architecture for providing Integrated Protection for Robust Communication power to the cable-side of the IC. 30kV ESD (HBM) on Driver Outputs/Receiver The device includes one half-duplex driver/receiver Inputs 2.75kV Withstand-Isolation Voltage for 60s (V ) channel. The receiver is 1/8-unit load, allowing up to 256 RMS ISO 630V Maximum Repetitive Peak-Isolation transceivers on a common bus. PEAK Voltage (V ) IORM Integrated true fail-safe circuitry ensures a logic-high on 445V Maximum Working-Isolation Voltage (V ) RMS IOWM the receiver output when inputs are shorted or open. > 30 Years Lifetime at Rated Working Voltage Undervoltage lockout disables the driver when cable-side Withstands 10kV Surge per IEC 61000-4-5 or UART-side power supplies are below functional levels. Thermal Shutdown The driver outputs/receiver inputs are protected from 30kV electrostatic discharge (ESD) to GNDB on the cable side, as specified by the Human Body Model (HBM). Functional Diagram The MAX14946 is available in a wide-body, 16-pin SOIC package and operates over the -40C to +85C temperature range. Applications V DDA TD1 TD2 VLDO Industrial Automation Equipment Programmable Logic Controllers MAX14946 HVAC LDO XFMR Power Meters DRIVER V DDB RE Safety Regulatory Approvals RXD A UL According to UL1577 TXD B DE DEM GNDA GNDB Ordering Information appears at end of data sheet. 19-7655 Rev 2 10/17 RS-485 TRANSCEIVERMAX14946 2.75kV Isolated 500kbps Half-Duplex RMS RS-485/RS-422 Transceiver with 30kV ESD Protection and Integrated Transformer Driver Absolute Maximum Ratings V to GNDA ......................................................-0.3V to +6V V to GNDB) ...................................................Continuous DDA DDB V to GNDB .......................................................-0.3V to +6V Continuous Power Dissipation (T = +70C) DDB A V to GNDB .....................................................-0.3V to +16V 16-pin Wide SOIC LDO TD1, TD2 to GNDA ..............................................-0.3V to +12V (derate 14.1mW/C above +70C) .........................1126.8mW TXD, DE, RE to GNDA ...........................................-0.3V to +6V Operating Temperature Range ........................... -40C to +85C RXD to GNDA.........................................-0.3V to (V + 0.3V) Junction Temperature ......................................................+150C DDA DEM to GNDB ........................................................-0.3V to +6V Storage Temperature Range ............................ -65C to +150C A, B to GNDB ...........................................................-8V to +13V Lead Temperature (soldering, 10s) .................................+300C TD1, TD2 Continuous Current ...........................................1.4A Soldering Temperature (reflow) .......................................+260C Short-Circuit Duration (RXD to GNDA, A, B, DEM, 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 = 3.0V to 5.5V, V - V = 4.5V to 5.5V, T = T to T , unless otherwise noted. Typical values are at DDA GNDA DDB GNDB A MIN MAX 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 3.0 5.5 DDA Supply Voltage V V 4.5 5.5 DDB V = 5V, DE = high, RE = TXD = DDA I low, RXD unconnected, no bus load, 4.7 7.7 DDA TD1/TD2 unconnected Supply Current mA DE = high, RE = TXD = low, RXD I 6.3 12.5 DDB unconnected, no bus load, V = 5V DDB RE, RXD, DE, TXD, V rising 1.50 1.58 1.65 DDA V UVLOA Undervoltage-Lockout TD1/TD2 driver, V rising 2.55 2.7 2.85 V DDA Threshold V V rising 2.55 2.7 2.85 UVLOB DDB RE, RXD, DE, TXD 50 V Undervoltage-Lockout- UVHYSTA TD1/TD2 driver 200 mV Threshold Hysteresis V 200 UVHYSTB TRANSFORMER DRIVER Output Resistance R TD1/TD2 = low, I = 300mA 0.6 1.5 O OUT 4.5V V 5.5V 540 785 1300 DDA TD1, TD2 Current Limit I mA LIM 3.0V V 3.6V 485 730 1170 DDA Switching Frequency f 350 450 550 kHz SW Duty Cycle D 50 % Crossover Dead Time t 50 ns DEAD Maxim Integrated 2 www.maximintegrated.com