EVALUATION KIT AVAILABLE 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver General Description The MAX14853/MAX14855 isolated RS-485/ RS-422 transceivers provide 2750VRMS (60s) of galvanic isolation between the cable-side (RS-485/RS-422 driver/ receiver-side) and the UART-side of the device. Isolation improves communication by breaking ground loops and reduces noise when there are large differences in ground potential between ports. These devices allow for robust communication up to 500kbps (MAX14853) or 25Mbps (MAX14855). The MAX14853/MAX14855 include an integrated 450kHz transformer driver for power transfer to the cable-side of the transceiver using an external transformer. An integrated LDO provides a simple and space-efficient architecture for providing power to the cable-side of the IC. The MAX14853/MAX14855 include one drive channel and one receive channel. The receiver is 1/4-unit load, allowing up to 128 transceivers on a common bus. Integrated true fail-safe circuitry ensures a logic-high on the receiver output when inputs are shorted or open. Undervoltage lockout disables the driver when cable-side or UART-side power supplies are below functional levels. The driver outputs and receiver inputs are protected from 35kV electrostatic discharge (ESD) to GNDB on the cable-side, as specified by the Human Body Model (HBM). The MAX14853/MAX14855 are available in a wide body 16-pin SOIC package and operate over the -40C to +105C temperature range. Benefits and Features Higher Integration Simplifies Designs * Integrated LDO for Powering Cable Side * Integrated Transformer Driver for Power Transfer to Cable Side High-Performance Transceiver Enables Flexible Designs * Compliant with RS-485 EIA/TIA-485 Standard * 500kbps (MAX14853)/25Mbps (MAX14855) Maximum Data Rate * Up to 128 Devices on the Bus * Slew-Rate Limited Outputs (MAX14853) * Integrated Receiver Deglitch Filter Increases Noise Immunity (MAX14853) Integrated Protection Ensures for Robust Communication * 35kV ESD (HBM) on Driver Outputs/Receiver Inputs * 2.75kVRMS Withstand Isolation Voltage for 60s (VISO) * 630VPEAK Maximum Repetitive Peak Isolation Voltage (VIORM) * 445VRMS Maximum Working Isolation Voltage (VIOWM) * > 30 Years Lifetime at Rated Working Voltage * Withstands 10kV Surge per IEC 61000-4-5 * Thermal Shutdown Functional Diagram Applications Industrial Automation Equipment Programmable Logic Controllers HVAC Power Meters Safety Regulatory Approvals UL According to UL1577 cUL According to CSA Bulletin 5A VDDA TD1 TD2 XFMR DRIVER VLDO LDO VDDB RE A RXD TXD DE Ordering Information appears at end of data sheet. 19-7546; Rev 5; 10/17 MAX14853 MAX14855 RS-485 TRANSCEIVER MAX14853/MAX14855 B Z Y GNDA GNDB MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Absolute Maximum Ratings VDDA to GNDA ........................................................-0.3V to +6V VDDB to GNDB........................................................-0.3V to +6V VLDO to GNDB......................................................-0.3V to +16V TD1, TD2 to GNDA ...............................................-0.3V to +12V TXD, DE, RE to GNDA ............................................-0.3V to +6V RXD to GNDA......................................... -0.3V to (VDDA + 0.3V) A, B, Y, Z to GNDB....................................................-8V to +13V TD1, TD2 Continuous Current..............................................1.4A Short-Circuit Duration (RXD to GNDA, A, B, Y, Z, VDDB to GNDB)....................................................Continuous Continuous Power Dissipation (TA = +70C) 16-pin Wide SOIC (derate 14.1mW/C above +70C).......................... 1126.8mW Operating Temperature Range.......................... -40C to +105C Junction Temperature.......................................................+150C Storage Temperature Range............................. -65C to +150C Lead Temperature (soldering, 10s).................................. +300C Soldering Temperature (reflow)........................................ +260C 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 (JA)...............71C/W Junction-to-Case Thermal Resistance (JC)....................23C/W 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 (VDDA - VGNDA = 3.0V to 5.5V, VDDB - VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA - VGNDA = 3.3V, VDDB - VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25C.) (Notes 2, 3) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER Supply Voltage VDDA 3.0 5.5 VDDB 3.0 5.5 IDDA VDDA = 5V, DE = high, RE = TXD = low, RXD unconnected, no load, TD1/TD2 unconnected 4.7 IDDB DE = high, RE = TXD = low, RXD unconnected, no load, VDDB = 3.3V 7.4 12.5 Supply Current Undervoltage Lockout Threshold Undervoltage Lockout Threshold Hysteresis VUVLOA VUVHYSTA 7.7 mA RE, RXD, DE, TXD 1.50 1.58 1.65 TD1/TD2 driver 2.55 2.7 2.85 2.55 2.7 2.85 VUVLOB V RE, RXD, DE, TXD V 50 TD1/TD2 driver 200 VUVHYSTB mV 200 TRANSFORMER DRIVER Output Resistance RO TD1, TD2 Current Limit ILIM Switching Frequency fSW Duty Cycle Crossover Dead Time www.maximintegrated.com TD1/TD2 = low, IOUT = 300mA 0.6 1.5 4.5V VDDA 5.5V 540 785 1300 3.0V VDDA 3.6V 485 730 1170 350 450 550 mA kHz D 50 % tDEAD 50 ns Maxim Integrated 2 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver DC Electrical Characteristics (continued) (VDDA - VGNDA = 3.0V to 5.5V, VDDB - VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA - VGNDA = 3.3V, VDDB - VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25C.) (Notes 2, 3) PARAMETER SYMBOL CONDITIONS MIN LDO Supply Voltage VLDO Relative to GNDB, LDO is on (Note 4) 3.18 LDO Supply Current ILDO DE = high, RE = TXD = low, no load, VLDO = 5.5V LDO Output Voltage VDDB TYP MAX UNITS 14 V 7.5 12.9 mA 3.3 3.6 V LDO 3.0 LDO Current Limit 300 mA Load Regulation VLDO = 3.3V, ILOAD = -20mA 0.19 1.7 mV/mA Line Regulation VLDO = 3.3V, ILOAD = -20mA 0.12 1.8 mV/V Dropout Voltage VLDO = 3.18V, IDDB = -120mA 100 180 mV Load Capacitance Nominal value (Note 5) 1 10 F 0.7 x VDDA LOGIC INTERFACE (TXD, RXD, DE, RE) V Input High Voltage VIH RE, TXD, DE to GNDA Input Low Voltage VIL RE, TXD, DE to GNDA VHYS RE, TXD, DE to GNDA 220 mV Input Capacitance CIN RE, TXD, DE, f = 1MHz 2 pF Input Pullup Current IPU TXD -10 -4.5 -1.5 A Input Pulldown Current IPD DE, RE 1.5 4.5 10 A Output Voltage High VOH RXD to GNDA, IOUT = -4mA Output Voltage Low VOL RXD to GNDA, IOUT = 4mA Input Hysteresis VDDA -0.4 V V 0.4 V 6.4 42 mA 0V VRXD VDDA, RE = low 5.5 40 mA 0V VRXD VDDA, RE = high -1 +1 A Short-Circuit Output Pullup Current ISH_PU 0V VRXD VDDA, RE = low Short-Circuit Output Pulldown Current ISH_PD IOZ Three-State Output Current 0.8 DRIVER Differential Driver Output |VOD| RL = 54, TXD = high or low, Figure 1a RL = 100, TXD = high or low, Figure 1a -7V VCM +12V, Figure 1b Change in Magnitude of Differential Driver Output Voltage VOD RL = 100 or 54, Figure 1a (Note 6) Driver Common-Mode Output Voltage VOC RL = 100 or 54, Figure 1a (Note 6) www.maximintegrated.com 1.5 V 2.0 1.5 5 VDDB/ 2 0.2 V 3 V Maxim Integrated 3 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver DC Electrical Characteristics (continued) (VDDA - VGNDA = 3.0V to 5.5V, VDDB - VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA - VGNDA = 3.3V, VDDB - VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25C.) (Notes 2, 3) PARAMETER Change in Magnitude of Common-Mode Voltage SYMBOL CONDITIONS VOC RL = 100 or 54, Figure 1a (Note 5) MIN TYP MAX UNITS 0.2 V GNDB VOUT +12V, output low (Note 7) +30 +250 -7V VOUT VDDB, output high (Note 7) -250 -30 Driver Short-Circuit Output Current IOSD Single-Ended Driver Output Voltage High VOH Y and Z outputs, IY,Z = -20mA Single-Ended Driver Output Voltage Low VOL Y and Z outputs, IY,Z = +20mA Differential Driver Output Capacitance COD DE = RE = high, f = 4MHz Input Current (A and B) IA, IB DE = GNDA, VDDB = VGNDB or 3.6V Receiver Differential Threshold Voltage VTH -7V VCM +12V mA 2.2 V 0.8 12 V pF RECEIVER VIN = +12V VIN = -7V Receiver Input Hysteresis VTH Receiver Input Resistance RIN -7V VCM +12V, DE = low CA,B Measured between A and B, DE = RE = GNDA at 2MHz Differential Input Capacitance +250 -200 -200 VCM = 0V -120 20 48 -10 A mV mV k 12 pF +160 C 15 C PROTECTION Thermal-Shutdown Threshold TSHDN Thermal-Shutdown Hysteresis THYST Temperature rising Human Body Model 35 IEC 61000-4-2 Air-Gap Discharge to GND 18 IEC 61000-4-2- Contact Discharge to GND 8 ESD Protection (A, B, Y, Z, GNDB Pins to GNDA) Human Body Model 8 kV ESD Protection (All Other Pins) Human Body Model 4 kV ESD Protection (A, B, Y, Z Pins to GNDB) www.maximintegrated.com kV Maxim Integrated 4 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Switching Electrical Characteristics (MAX14853) (VDDA - VGNDA = 3.0V to 5.5V, VDDB - VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA - VGNDA = 3.3V, VDDB - VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25C.) (Note 5) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DYNAMIC Common-Mode Transient Immunity CMTI Glitch Rejection (Note 8) TXD, DE, RXD 35 10 17 kV/s 29 ns DRIVER tDPLH, tDPHL RL = 54, CL = 50pF, Figure 2 and Figure 3 1040 ns Differential Driver Output Skew |tDPLH - tDPHL| tDSKEW RL = 54, CL = 50pF, Figure 2 and Figure 3 144 ns Driver Differential Output Rise or Fall Time tLH, tHL RL = 54, CL = 50pF, Figure 2 and Figure 3 900 ns Maximum Data Rate DRMAX Driver Propagation Delay 500 kbps Driver Enable to Output High tDZH RL = 110, CL = 50pF, Figure 4 2540 ns Driver Enable to Output Low tDZL tDLZ RL = 110, CL = 50pF, Figure 5 2540 ns Driver Disable Time From Low RL = 110, CL = 50pF, Figure 5 140 ns Driver Disable Time From High tDHZ RL = 110, CL = 50pF, Figure 4 140 ns tRPLH, tRPHL CL = 15pF, Figure 6 and Figure 7 (Note 9) 240 ns Receiver Output Skew tRSKEW CL = 15pF, Figure 6 and Figure 7 (Note 9) 34 ns Maximum Data Rate DRMAX RECEIVER Receiver Propagation Delay 500 kbps Receiver Enable to Output High tRZH RL = 1k, CL = 15pF, S2 closed, Figure 8 20 ns Receiver Enable to Output Low tRZL RL = 1k, CL = 15pF, S1 closed, Figure 8 30 ns Receiver Disable Time From Low tRLZ RL = 1k, CL = 15pF, S1 closed, Figure 8 20 ns Receiver Disable Time From High tRHZ RL = 1k, CL = 15pF, S2 closed, Figure 8 20 ns www.maximintegrated.com Maxim Integrated 5 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Switching Electrical Characteristics (MAX14855) (VDDA - VGNDA = 3.0V to 5.5V, VDDB - VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA - VGNDA = 3.3V, VDDB - VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25C.) (Note 5) PARAMETER DYNAMIC Common-Mode Transient Immunity Glitch Rejection DRIVER SYMBOL Driver Propagation Delay tDPLH, tDPHL Differential Driver Output Skew |tDPLH - tDPHL| CMTI CONDITIONS MIN (Note 8) TXD, DE, RXD TYP MAX 35 10 17 UNITS kV/s 29 ns RL = 54, CL = 50pF, Figure 2 and Figure 3 65 ns tDSKEW RL = 54, CL = 50pF, Figure 2 and Figure 3 7 ns Driver Differential Output Rise or Fall Time tLH, tHL RL = 54, CL = 50pF, Figure 2 and Figure 3 10 ns Maximum Data Rate DRMAX 25 Mbps Driver Enable to Output High tDZH RL = 110, CL = 50pF, Figure 4 80 ns Driver Enable to Output Low tDZL RL = 110, CL = 50pF, Figure 5 80 ns Driver Disable Time from Low tDLZ RL = 110, CL = 50pF, Figure 5 80 ns Driver Disable Time from High tDHZ RL = 110, CL = 50pF, Figure 4 80 ns tRPLH, tRPHL CL = 15pF, Figure 6 and Figure 7 (Note 9) 65 ns Receiver Output Skew tRSKEW CL = 15pF, Figure 6 and Figure 7 (Note 9) 7 ns Maximum Data Rate DRMAX RECEIVER Receiver Propagation Delay 25 Receiver Enable to Output High tRZH Receiver Enable to Output Low tRZL RL = 1k, CL = 15pF, S2 closed, Figure 8 RL = 1k, CL = 15pF, S1 closed, Figure 8 Receiver Disable Time from Low tRLZ Receiver Disable Time from High tRHZ Mbps 20 ns 30 ns RL = 1k, CL = 15pF, S1 closed, Figure 8 20 ns RL = 1k, CL = 15pF, S2 closed, Figure 8 20 ns Note 2: All devices are 100% production tested at TA = +25C. Specifications over temperature are guaranteed by design. Note 3: All currents into the device are positive. All currents out of the device are negative. All voltages are referenced to their respective ground (GNDA or GNDB), unless otherwise noted. Note 4: VLDO max indicates voltage capability of the circuit. Power dissipation requirements may limit VLDO max to a lower value. Note 5: Not production tested. Guaranteed by design. Note 6: VOD and VOC are the changes in VOD and VOC, respectively, when the TXD input changes state. Note 7: The short-circuit output current applies to the peak current just prior to current limiting. Note 8: CMTI is the maximum sustainable common-mode voltage slew rate while maintaining the correct output states. CMTI applies to both rising and falling common-mode voltage edges. Tested with the transient generator connected between GNDA and GNDB. Note 9: Capacitive load includes test probe and fixture capacitance. www.maximintegrated.com Maxim Integrated 6 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Insulation Characteristics PARAMETER Partial DischargeTest Voltage SYMBOL VPR CONDITIONS VALUE UNITS Method B1 = VIORM x 1.875 (t = 1s, partial discharge < 5pC) 1182 VP Maximum Repetitive Peak Isolation Voltage VIORM (Note 10) 630 VP Maximum Working Isolation Voltage VIOWM (Note 10) 445 VRMS Maximum Transient Isolation Voltage VIOTM t = 1s 4600 VP Maximum Withstand Isolation Voltage VISO VIOSM t = 60s, f = 60Hz (Notes 10, 11) 2750 VRMS 10 kV >109 Maximum Surge Isolation Voltage Insulation Resistance RS Basic insulation TA = +150C, VIO = 500V Barrier Capacitance Input-to-Output CIO f = 1MHz 2 pF Minimum Creepage Distance CPG Wide SO 8 mm Minimum Clearance Distance CLR Wide SO 8 mm 0.015 mm Internal Clearance Comparative Tracking Resistance Index Distance through insulation CTI Material Group II (IEC 60112) Climatic Category Pollution Degree (DIN VDE 0110, Table 1) 575 40/125/21 2 Note 10: VIORM, VIOWM, and VISO are defined by the IEC 60747-5-5 standard. Note 11: Product is qualified VISO for 60 seconds. 100% production tested at 120% of VISO for 1s. Safety Regulatory Approvals UL The MAX14853/MAX14855 is certified under UL1577. For more details, see file E351759. Rate up to 2750VRMS isolation voltage for basic insulation. cUL The MAX14853/MAX14855 is certified under UL1577. For more details, see File E351759. Rate up to 2750VRMS isolation voltage for basic insulation. www.maximintegrated.com Maxim Integrated 7 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver 375 Y Y RL 2 VOD VOD RL 2 60 + VCM - VOC Z Z 375 (b) (a) Figure 1. Driver DC Test Load Y TXD Z VOD RL CL GNDA Figure 2. Driver Timing Test Circuit tLH P 3ns, tHL P 3ns VDDA 50% TXD 50% GNDA 1/2 VO tDPHL tDPLH Z Y 1/2 VO VO VDIFF = VY - VZ VO 80% 80% VDIFF 0 20% 20% tLH -VO tHL tDSKEW = |tDPLH - tDPHL| Figure 3. Driver Propagation Delays www.maximintegrated.com Maxim Integrated 8 MAX14853/MAX14855 Y GNDA OR VDDA TXD D Z DE 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver S1 VDDA OUT CL 50pF DE RL = 500I 50% 250mV OUT GENERATOR 50% GNDB 50I GNDA tDZH tDHZ VOH GNDB GNDA Figure 4. Driver Enable and Disable Times (tDZH, tDHZ) VDDB GNDA OR VDDA TXD D Y Z DE GENERATOR RL = 500I S1 OUT CL = 50pF GNDB 50I GNDA VDDA DE 50% GNDA tDZL tDLZ VDDB 50% OUT 250mV VOL Figure 5. Driver Enable and Disable Times (tDZL, tDLZ) A ATE R VID RECEIVER OUTPUT B Figure 6. Receiver Propagation Delay Test Circuit www.maximintegrated.com Maxim Integrated 9 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver t = 1MHz, tLH P 3ns, tHL P 3ns A 1V B -1V tRPHL tRPLH VDDA 2 RXD VOH VDDA 2 VOL tRSKEW = |tRPHL - tRPLH| Figure 7. Receiver Propagation Delays +1.5V S3 -1.5V VID GNDB GENERATOR R RE RXD RL 1kI S1 VDDA S2 CL 15pF GNDA 50I GNDA VDDA VDDA 50% RE S1 OPEN S2 CLOSED GNDA S3 = +1.5V 50% RE GNDA tRZL tRZH VOH VDDA 2 GNDA RXD VDDA 50% RE VDDA 2 RXD S1 OPEN S2 CLOSED S3 = +1.5V VDDA RE 50% GNDA GNDA RXD VDDA VOL S1 CLOSED S2 OPEN S3 = -1.5V tRLZ tRHZ 0.25V S1 CLOSED S2 OPEN S3 = -1.5V VDDA VOH RXD GNDA 0.25V VOL Figure 8. Receiver Enable and Disable Times www.maximintegrated.com Maxim Integrated 10 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Typical Operating Characteristics (VDDA - VGNDA = 3.3V, VDDB - VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25C, unless otherwise noted.) VDDA SUPPLY CURRENT vs. TEMPERATURE 8 toc01 14 7 3.5 8 6 NO LOAD NO SWITCHING TD1/TD2 UNCONNECTED 1 NO LOAD NO SWITCHING 15 30 45 60 75 90 105 TEMPERATURE (C) 240 220 900 0 15 30 45 60 75 90 105 -45 -30 -15 PROPAGATION DELAY (ns) 800 700 tPDHL 500 400 tPDLH 200 100 1000 C L = 15pF 180 160 140 120 100 tRPLH 80 60 0 -45 -30 -15 0 15 30 45 60 75 90 105 TEMPERATURE (C) 0 15 30 45 60 75 90 105 700 600 tDZH tDZL 500 400 300 200 tDHZ tDLZ -45 -30 -15 toc08 RXD 2V/div VINSIDE 0V 0V VBACKUP Y 1V/div B 1V/div Z 1V/div A 1V/div PROPAGATION DELAY (ns) VOUTN 100ns/div 0 15 30 45 60 75 90 105 TEMPERATURE (C) C L = 15pF 100ns/div 75 800 90 105 TXD 2V/div R L = 54 C L = 50pF 60 0 -45 -30 -15 MAX14853 RECEIVER PROPAGATION DELAY toc07 45 MAX14853 DRIVER ENABLE/DISABLE DELAY vs. TEMPERATURE toc06 TEMPERATURE (C) MAX14853 DRIVER PROPAGATION DELAY 30 100 20 0 15 900 tRPHL 40 R L = 54 C L = 50pF 0 TEMPERATURE (C) MAX14853 RECEIVER PROPAGATION DELAY vs. TEMPERATURE toc05 200 300 54 LOAD TEMPERATURE (C) MAX14853 TRANSMITTER PROPAGATION DELAY vs. TEMPERATURE toc04 600 120 LOAD 0.0 -45 -30 -15 ENABLE/DISABLE DELAY (ns) 0 2.0 0.5 0 -45 -30 -15 2.5 1.0 2 0 toc03 NO LOAD 1.5 4 2 DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE 3.0 VOD (V) IDDB (mA) 4 3 PROPAGATION DELAY (ns) 4.0 10 5 1000 toc02 12 6 IDDA (mA) VDDB SUPPLY CURRENT vs. TEMPERATURE 65 60 55 50 45 40 35 30 25 20 15 10 5 0 MAX14855 TRANSMITTER PROPAGATION DELAY vs. TEMPERATURE toc09 tPDHL tPDLH R L = 54 C L = 50pF -45 -30 -15 0 15 30 45 60 75 90 105 TEMPERATURE (C) www.maximintegrated.com Maxim Integrated 11 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Typical Operating Characteristics (continued) MAX14855 RECEIVER PROPAGATION DELAY vs. TEMPERATURE toc10 65 60 55 50 45 40 35 30 25 20 15 10 5 0 MAX14855 DRIVER ENABLE/DISABLE DELAY vs. TEMPERATURE toc11 80 70 ENABLE/DISABLE DELAY (ns) PROPAGATION DELAY (ns) (VDDA - VGNDA = 3.3V, VDDB - VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25C, unless otherwise noted.) tRPHL tRPLH tDZH tDHZ 60 50 40 30 tDZL tDLZ 20 10 C L = 15pF 0 -45 -30 -15 0 15 30 45 60 75 90 105 -45 -30 -15 0 TEMPERATURE (C) 15 30 45 60 75 90 105 TEMPERATURE (C) MAX14855 DRIVER PROPAGATION DELAY MAX14855 RECEIVER PROPAGATION DELAY toc12 toc13 R L = 54 C L = 50pF TXD 2V/div VOUTN 0V VINSIDE Y 1V/div VBACKUP A 1V/div VOUTN VINSIDE B 1V/div VBACKUP RXD 2V/div 0V Z 1V/div C L = 15pF 10ns/div 10ns/div RECEIVER ENABLE/DISABLE DELAY vs. TEMPERATURE 20 toc14 18 7 16 14 tRZL 12 tRZH tRHZ 10 toc15 54 LOAD 120 LOAD 6 5 IDDA (mA) ENABLE/DISABLE DELAY (ns) VDDA SUPPLY CURRENT vs. DATA RATE 8 tRLZ 8 4 3 6 2 4 1 2 0 0 -45 -30 -15 0 15 30 45 60 TEMPERATURE (C) www.maximintegrated.com 75 90 105 0.01 0.1 1 10 100 DATA RATE (Mbps) Maxim Integrated 12 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Typical Operating Characteristics (continued) (VDDA - VGNDA = 3.3V, VDDB - VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25C, unless otherwise noted.) VDDB SUPPLY CURRENT vs. DATA RATE 70 toc16 600 SWITCHING FREQUENCY (kHz) 60 54 LOAD IDDB (mA) 50 40 30 20 120 LOAD 10 TRANSFORMER DRIVER SWITCHING FREQUENCY vs. TEMPERATURE toc17 550 500 450 400 350 NO LOAD 0 300 0.01 0.1 1 10 100 -45 -30 -15 DATA RATE (Mbps) 15 30 45 60 75 90 105 TEMPERATURE (C) TD1/TD2 VOLTAGE vs. DRIVE CURRENT 400 0 TRANSFORMER DRIVER toc18 toc19 TD1/TD2 DRIVER VOLTAGE (mV) 350 300 VOUTN 250 VINSIDE TD1 & TD2 2V/div 200 VBACKUP 150 0V 100 50 100mA LOAD ON VDDB 0 0 100 200 300 400 500 600 700 400ns/div DRIVER CURRENT (mA) www.maximintegrated.com Maxim Integrated 13 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Pin Configuration TOP VIEW + TD1 1 16 VDDB TD2 2 GNDA 3 VDDA 4 13 B RXD 5 12 Z RE 6 11 Y DE 7 10 VLDO TXD 8 9 MAX14853 MAX14855 15 GNDB 14 A GNDB SOIC Pin Description PIN NAME REFERENCE 1 TD1 GNDA Transformer Driver Output 1 2 TD2 GNDA Transformer Driver Output 2 3 GNDA -- 4 VDDA GNDA UART/Logic-Side Power Input. Bypass VDDA to GNDA with both 0.1F and 1F capacitors as close as possible to the device. 5 RXD GNDA Receiver Data Output. Drive RE low to enable RXD. With RE low, RXD is high when (VA - VB) > -10mV and is low when (VA - VB) < -200mV. RXD is high when VDDB is less than VUVLOB. RXD is high impedance when RE is high. 6 RE GNDA Receiver Output Enable. Drive RE low or connect to GNDA to enable RXD. Drive RE high to disable RXD. RXD is high impedance when RE is high. RE has an internal 4.5A pulldown to GNDA. www.maximintegrated.com FUNCTION UART/Logic-Side Ground. GNDA is the ground reference for digital signals and the transformer driver. Maxim Integrated 14 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Pin Description (continued) PIN NAME REFERENCE FUNCTION 7 DE GNDA Driver Output Enable. Drive DE high to enable bus driver outputs Y and Z. Drive DE low or connect to GNDA to disable Y and Z. Y and Z are high impedance when DE is low. DE has an internal 4.5A pulldown to GNDA. 8 TXD GNDA Driver Input. With DE high, a low on TXD forces the noninverting output (Y) low and the inverting output (Z) high. Similarly, a high on TXD forces the noninverting output high and the inverting output low. TXD has an internal 4.5A pullup to VDDA. 9, 15 GNDB -- Cable-Side Ground. GNDB is the ground reference for the internal LDO and the RS-485/ RS-422 bus signals. 10 VLDO GNDB LDO Power Input. Connect a minimum voltage of 3.18V to VLDO to power the cable-side of the transceiver. Bypass VLDO to GNDB with both 0.1F and 1F capacitors as close as possible to the device. To disable the internal LDO, leave VLDO unconnected or connect to GNDB. 11 Y GNDB Noninverting Driver Output 12 Z GNDB Inverting Driver Output 13 B GNDB Inverting Receiver Input 14 A GNDB Noninverting Receiver Input GNDB Cable-Side Power Input/Isolated LDO Power Output. Bypass VDDB to GNDB with both 0.1F and 1F capacitors as close as possible to the device. VDDB is the output of the internal LDO when power is applied to VLDO. When the internal LDO is not used (VLDO is unconnected or connected to GNDB), VDDB is the positive supply input for the cable-side of the IC. 16 VDDB www.maximintegrated.com Maxim Integrated 15 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Function Tables TRANSMITTING INPUTS OUTPUTS VDDA VDDB DE TXD Y Z VUVLOA VUVLOB 1 1 1 0 VUVLOA VUVLOB 1 0 0 1 VUVLOA VUVLOB 0 X High-Z High-Z < VUVLOA VUVLOB X X High-Z High-Z VUVLOA < VUVLOB X X High-Z High-Z < VUVLOA < VUVLOB X X High-Z High-Z Note: Drive DE low to disable the transmitter outputs. Drive DE high to enable the transmitter outputs. DE has an internal pulldown to GNDA. X = Don't care. RECEIVING INPUTS OUTPUTS VDDA VDDB RE (VA - VB) RXD VUVLOA VUVLOB 0 > -10mV 1 VUVLOA VUVLOB 0 < -200mV 0 VUVLOA VUVLOB 0 Open/Short 1 VUVLOA VUVLOB 1 X High-Z < VUVLOA VUVLOB X X High-Z VUVLOA < VUVLOB 0 X 1 < VUVLOA < VUVLOB X X High-Z Note: Drive RE high to disable the receiver output. Drive RE low to enable to receiver output. RE has an internal pulldown to GNDA. X = Don't care. www.maximintegrated.com Maxim Integrated 16 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Detailed Description The MAX14853/MAX14855 isolated RS-485/RS-422 transceivers provide 2750VRMS (60s) of galvanic isolation between the RS-485/RS-422 cable-side of the transceiver and the UART-side. These devices allow up to 500kbps (MAX14853) or 25Mbps (MAX14855) communication across an isolation barrier when a large potential exists between grounds on each side of the barrier. Isolation Both data and power can be transmitted across the isolation barrier. Data isolation is achieved using integrated capacitive isolation that allows data transmission between the UARTside and the cable-side of the transceiver. To achieve power isolation, the MAX14853/MAX14855 feature an integrated transformer driver to drive an external center-tapped transformer, allowing the transfer of operating power from the UART-side across the isolation barrier to the cable-side. Connect the primary side of the external transformer to the MAX14853/MAX14855's transformer driver outputs (TD1 and TD2). The MAX14853 features a slew-rate limited driver that minimizes EMI and reduces reflections caused by improperly terminated cables, allowing error-free data transmission at data rates up to 500kbps. The MAX14853 also includes an added deglitch filter on the receiver signal path for enhanced noise immunity when differential signals have very slow rise and fall times. Integrated LDO The MAX14853/MAX14855 include an internal low-dropout regulator with a set 3.3V (typ) output that is used to power the cable-side of the IC. The output of the LDO is VDDB. The LDO has a 300mA (typ) current limit. If the LDO is unused, connect VLDO to GNDB and apply +3.3V directly to VDDB. True Fail-Safe The MAX14853/MAX14855 guarantee a logic-high on the receiver output when the receiver inputs are shorted or open, or when connected to a terminated transmission line with all drivers disabled. The receiver threshold is fixed between -10mV and -200mV. If the differential receiver input voltage (VA - VB) is greater than or equal to -10mV, RXD is logic high. In the case of a terminated bus with all transmitters disabled, the receiver's differential input voltage is pulled to zero by the termination resistors. Due to the receiver thresholds of the MAX14853/MAX14855, this results in a logic-high at RXD. www.maximintegrated.com Driver Output Protection Two mechanisms prevent excessive output current and power dissipation caused by faults or by bus contention. The first, a current limit on the output stage, provides immediate protection against short circuits over the entire common-mode voltage range. The second, a thermal-shutdown circuit, forces the driver outputs into a high-impedance state if the die temperature exceeds +160C (typ). Thermal Shutdown The MAX14853/MAX14855 are protected from overtemperature damage by integrated thermal-shutdown circuitry. When the junction temperature (TJ) exceeds +160C (typ), the driver outputs go high impedance. The device resumes normal operation when TJ falls below +145C (typ). Transformer Driver Overcurrent Limiting The MAX14853/MAX14855 feature overcurrent limiting to protect the integrated transformer driver from excessive currents when charging large capacitive loads or driving into short-circuits. Current limiting is achieved in two stages: internal circuitry monitors the output current and detects when the peak current rises above 1.2A. When the 1.2A threshold is exceeded, internal circuitry reduces the output current to the 730mA current-limit. The MAX14853/MAX14855 monitor the driver current on a cycle-by-cycle basis and limit the current until the short is removed. The transformer driver on the MAX14853/MAX14855 can dissipate large amounts of power during overcurrent limiting, causing the IC to enter thermal shutdown. Transformer Selection The integrated push-pull transformer driver allows the transmission of operating power from the logic side, across the isolation barrier, to the isolated field side of the device. The 450kHz transformer driver operates with center-tapped primary and secondary transformers. Select a transformer with an ET product greater than or equal to the ET of the driver to ensure that the transformer does not enter saturation. E is the voltage applied to the transformer and T is the maximum time it is applied during any one cycle. Calculate the minimum ET product for the transformer primary as: ET = VMAX/(2 x fMIN) Where VMAX is the worst-case maximum supply voltage on VDDA and fMIN is the minimum frequency at that supply voltage. For example, using 5.5V and 350kHz, the required minimum ET product is 7.9Vs. Maxim Integrated 17 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Applications Information Extended ESD Protection 128 Transceivers on the Bus The standard RS-485 receiver input impedance is one unit load, and a standard driver can drive up to 32 unit loads. The MAX14853/MAX14855 transceivers have a 1/4-unit load receiver, allowing up to 128 transceivers connected in parallel on one communication line. Connect any combination of these devices, and/or other RS-485 devices, for a maximum of 32 unit loads to the line. Typical Application The MAX14853/MAX14855 full-duplex transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figure 9 and Figure 10 show typical network applications circuits. To minimize reflections, the bus should be terminated at the receiver input in its characteristics impedance, and stub lengths off the main line should be kept as short as possible. Layout Considerations It is recommended to design an isolation or keep-out channel underneath the isolator that is free from ground and signal planes. Any galvanic or metallic connection between the cable-side and UART-side defeats the isolation. Ensure that the decoupling capacitors between VDDA and GNDA and between VLDO, VDDB, and GNDB are located as close as possible to the IC to minimize inductance. ESD protection structures are incorporated on all pins to protect against electrostatic discharge encountered during handling and assembly. The driver outputs and receiver inputs of the MAX14853/MAX14855 have extra protection against static electricity. The ESD structures withstand high ESD in normal operation and when powered down. After an ESD event, the devices keep working without latch-up or damage. Bypass VDDA to GNDA and bypass VDDB and VLDO to GNDB with both 0.1F and 1F capacitors to ensure maximum ESD protection. ESD protection can be tested in various ways. The transmitter outputs and receiver inputs of the MAX14853/ MAX14855 are characterized for protection to the cableside ground (GNDB) to the following limits: 35kV HBM 18kV using the Air-Gap Discharge method specified in IEC 61000-4-2 8kV using the Contact Discharge method specified in the IEC 61000-4-2 The transmitter outputs and receiver inputs also include extended ESD protection with reference to the UART-side ground (GNDA) to the following limits: 8kV HBM Route important signal lines close to the ground plane to minimize possible external influences. On the cable-side of the MAX14853/MAX14855, it is good practice to have the bus connectors and termination resistor as close as possible to the A and B pins. Table 1. Recommended Transformers MANUFACTURER PART NUMBER APPLICATION CONFIGURATION ISOLATION (VRMS) DIMENSIONS (L x W x H) (mm) HALO TGMS-1450V6LF 5V to 3.3V 1CT: 1CT 2750 9.45 x 10.87 x 10.03 HALO TGMS-1455V6LF 3.3V to 3.3V 1CT: 1.5CT 2750 9.45 x 10.87 x 10.03 WURTH 750315225 5V to 3.3V 1CT: 1.1CT 2750 6.73 x 7.14 x 4.19 WURTH 750315226 5V to 3.3V 1CT: 1.3CT 2750 6.73 x 7.14 x 4.19 WURTH 750315227 3.3V to 3.3V 1CT: 1.7CT 2750 6.73 x 7.14 x 4.19 www.maximintegrated.com Maxim Integrated 18 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Slave RXD RE TXD DE RS-485 TRANSCEIVER RS-485 TRANSCEIVER Master A Y 120 Z B B B A RS-485 TRANSCEIVER RXD RE TXD DE A RS-485 TRANSCEIVER MAX14853 MAX14855 INTEGRATED ISOLATION BARRIER Slave DE TXD RE RXD DE TXD RE Slave RXD Figure 9. Typical Isolated Full-Duplex RS-485/RS-422 Application VDDA 1 2 VLDO TD2 VDDA RXD RE 2 3 VDDB VDDB TXD DE A 0.1F 2 2 0.1F 3 3 VLDO TD2 TD1 VDDA 1F 3 Y B Z Y A Z B MAX14853 MAX14855 1 4 1F 0.1F 0.1F 1F RS-485 TRANSCEIVER 1 10F 3 2 RS-485 TRANSCEIVER 1 1F TD1 1F 3 2 2 10F VDDA 10F 10F 1F 4 0.1F 4 RXD RE TXD DE MAX14853 MAX14855 3 4 Figure 10. Typical Isolated RS-485/RS-422 Application with Integrated Transformer Driver www.maximintegrated.com Maxim Integrated 19 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver ESD Test Conditions ESD performance depends on a variety of conditions. Contact Maxim for a reliability report that documents test setup, test methodology, and test results. Human Body Model (HBM) Figure 11 shows the HBM test model and Figure 12 shows the current waveform it generates when discharged in a low-impedance state. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged in to the test device through a 1.5k resistor. RC 1M CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF RD 1500 The major difference between tests done using the HBM and IEC 61000-4-2 is higher peak current in IEC 610004-2 because series resistance is lower in the IEC 610004-2 model. Hence, the ESD withstand voltage measured to IEC 61000-4-2 is generally lower than that measured using the HBM. Figure 13 shows the IEC 61000-4-2 model and Figure 14 shows the current waveform for IEC 61000-4-2 ESD Contact Discharge Test. IP 100% 90% DISCHARGE RESISTANCE STORAGE CAPACITOR IEC 61000-4-2 The IEC 61000-4-2 standard covers ESD testing and performance of finished equipment. However, it does not specifically refer to integrated circuits. The MAX14853/ MAX14855 help in designing equipment to meet IEC 61000-4-2 without the need for additional ESD protection components. Ir AMPS DEVICE UNDER TEST 36.8% 10% 0 0 Figure 11. Human Body ESD Test Model CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 150pF tDL CURRENT WAVEFORM Figure 12. Human Body Current Waveform RD 330 I 100% 90% DISCHARGE RESISTANCE STORAGE CAPACITOR TIME tRL IPEAK RC 50M TO 100M PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) DEVICE UNDER TEST 10% tr = 0.7ns TO 1ns t 30ns 60ns Figure 13. IEC 61000-4-2 ESD Test Model www.maximintegrated.com Figure 14. IEC 61000-4-2 ESD Generator Current Waveform Maxim Integrated 20 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Typical Application Circuit VDDA TD1 VLDO TD2 VDDA VDDB XFMR DRIVER LDO A C RS-485 TRANSCEIVER RXD RE TXD DE B Z Y MAX14853 MAX14855 GNDA GNDB ISOLATION BARRIER Ordering Information DATA RATE (MAX) DRIVER SLEW RATE LIMITED RECEIVER DEGLITCHING TEMP RANGE PIN-PACKAGE MAX14853GWE+ 500kbps YES YES -40C to +105C 16 SOIC (W) MAX14853GWE+T 500kbps YES YES -40C to +105C 16 SOIC (W) MAX14855GWE+ 25Mbps NO NO -40C to +105C 16 SOIC (W) MAX14855GWE+T 25Mbps NO NO -40C to +105C 16 SOIC (W) PART +Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and Reel Chip Information PROCESS: BiCMOS www.maximintegrated.com Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 16 SOIC W16M+10 21-0042 90-0107 Maxim Integrated 21 MAX14853/MAX14855 2.75kVRMS Isolated 500kbps/25Mbps Full-Duplex RS-485/RS-422 Transceivers with 35kV ESD Protection and Integrated Transformer Driver Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 3/15 Initial release 1 4/15 Updated Electrical Characteristics notes, Typical Operating Characteristics graph, and Driver Output Protection section 2 10/15 Updated Benefits and Feature and Isolation sections and added Recommended Transformers table 3 1/16 Corrected typos, updated Figures 1-4, and Figure 6 4 1/17 Updated pending safety approvals 1, 7 5 10/17 Corrected RXD voltage for RXD in Absolute Maxim Ratings and updated Table 1 2,18 DESCRIPTION -- 6, 13, 17 1, 17, 18, 22 1, 8, 9, 16, 17, 19, 22 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated's website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. (c) 2017 Maxim Integrated Products, Inc. 22 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Maxim Integrated: MAX14855GWE+ MAX14855GWE+T MAX14853GWE+ MAX14853GWE+T