EVALUATION KIT AVAILABLE MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection General Description The MAX14941/MAX14942 isolated RS-485/PROFIBUS-DP transceivers provide 5000VRMS (60s) of galvanic isolation between the cable-side (RS-485 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 20Mbps. An integrated LDO provides a simple and space-efficient architecture for providing power to the cable side of the IC. Each device includes one half-duplex driver/receiver 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/receiver inputs are protected from ±35kV electrostatic discharge (ESD) to GNDB on the cable side, as specified by the Human Body Model (HBM). The MAX14941/MAX14942 are available in a wide-body 16-pin SOIC package and operate over the -40°C to +105°C temperature range. VLDO LDO (PV) ●● High-Performance Transceiver Enables Flexible Designs • Integrated LDO for Cable-Side Power • Compliant with RS-485 EIA/TIa-485 Standard • 20Mbps Maximum Data Rate • Allows Up to 128 Devices on the Bus ●● Integrated Protections Ensures Robust Communication • ±35kV ESD (HBM) on Driver Outputs/Receiver Inputs • 5kVRMS Withstand Isolation Voltage for 60s (VISO) • 1200VPEAK Maximum Repetitive Peak-Isolation Voltage (VIORM) • 848VRMS Maximum Working-Isolation Voltage (VIOWM) • > 30 Years Lifetime at Rated Working Voltage • Withstands ±10kV Surge per IEC 61000-4-5 • Thermal Shutdown Safety Regulatory Approvals Pending ●● UL According to UL1577 ●● cUL According to CSA Bulletin 5A ●● VDE 0884-10 Applications ●● ●● ●● ●● Functional Diagram VDDA Benefits and Features MAX14941 MAX14942 VDDB Industrial Automation Equipment Programmable Logic Controllers HVAC Power Meters Ordering Information appears at end of data sheet. RS-485 TRANSCEIVER SBA* RXD RE TXD DE A B (DEM) GNDA 19-8116; Rev 0; 11/15 GNDB () MAX14941 only * MAX14942 only The PROFIBUS PROCESS FIELD BUS logo is a registered trademark of PROFIBUS and PROFINET International (PI) MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Absolute Maximum Ratings VDDA to GNDA .......................................................-0.3V to +6V VDDB to GNDB........................................................-0.3V to +6V VLDO to GNDB......................................................-0.3V to +16V TXD, DE, RE, PV to GNDA .....................................-0.3V to +6V SBA, RXD to GNDA .............................. -0.3V to (VDDA + 0.3V) DEM to GNDB ....................................... -0.3V to (VDDB + 0.3V) A, B to GNDB............................................................-8V to +13V Short Circuit Duration (RXD, SBA to GNDA, A, B, DEM ,VDDB to GNDB)..................................Continuous Continuous Power Dissipation (TA = +70°C) 16-pin W SOIC (derate 14.1mW/°C above +70°C).......................................................... 1126.8mW Operating Temperature Range.......................... -40°C to +105°C Junction Temperature.......................................................+150°C Storage Temperature Range............................. -65°C to +150°C Lead Temperature (soldering, 10s).................................. +300°C Soldering Temperature (reflow)........................................+260°C 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 (θJA)...............71°C/W Junction-to-Case Thermal Resistance (θJC)....................23°C/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 = 1.71V to 5.5V, VDDB – VGNDB = 4.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA – VGNDA = 3.3V, VDDB – VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER Supply Voltage Supply Current VDDA 1.71 5.5 VDDB 4.5 5.5 IDDA VDDA = 5V, DE = high, RE = TXD = low, RXD unconnected, no bus load 4 6.6 IDDB DE = high, RE = TXD = low, RXD unconnected, no bus load, VDDB = 5V 7.6 12.5 VUVLOA VDDA rising 1.50 1.58 1.65 VDDB rising 2.55 2.7 2.85 Undervoltage Lockout Threshold VUVLOB Undervoltage Lockout Threshold Hysteresis VUVHYSTA 50 VUVHYSTB 200 V mA V mV LDO LDO Supply Voltage VLDO Relative to GNDB, LDO is on (Note 4) LDO Supply Current ILDO DE = high, TXD = low, no bus load, VLDO = 5V LDO Output Voltage VDDB 4.68 4.5 LDO Current Limit 14 V 7.7 12.9 mA 5 5.5 V 300 mA Load Regulation VLDO = 5.68V, ILOAD = 20mA to 40mA 0.19 1.7 mV/mA Line Regulation VLDO = 5.68V to 14V, ILOAD = 20mA 0.12 1.8 mV/V www.maximintegrated.com Maxim Integrated │ 2 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection DC Electrical Characteristics (continued) (VDDA – VGNDA = 1.71V to 5.5V, VDDB – VGNDB = 4.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA – VGNDA = 3.3V, VDDB – VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3) PARAMETER SYMBOL CONDITIONS Dropout Voltage VLDO = 4.68V, IDDB = 120mA Load Capacitance Nominal value (Note 8) LOGIC INTERFACE (TXD, RXD, DE, RE, SBA, PV, DEM) Input High Voltage VIH RE, TXD, DE, PV to GNDA Input Low Voltage VIL RE, TXD, DE, PV to GNDA Input Hysteresis MIN TYP MAX UNITS 100 180 mV 10 µF 1 2.25V < VDDA < 5.5V 0.7 x VDDA 1.71V < VDDA < 1.89V 2.25V < VDDA < 5.5V 1.71V < VDDA < 1.89V 0.78 x VDDA V 0.8 0.6 V VHYS RE, TXD, DE, PV to GNDA 220 mV Input Capacitance CIN RE, TXD, DE, PV, f = 1MHz 2 pF Input Pull-Up Current TXD, PV -10 -4.5 -1.5 Input Pull-Down Current IPU IPD DE, RE 1.5 4.5 10 µA SBA Pull-Up Resistance RSBA 3 5 8 kΩ Output Voltage High Output Voltage Low Short Circuit Output Pull-Up Current Short Circuit Output Pull-Down Current Tri-State Output Current DRIVER Differential Driver Output www.maximintegrated.com VOH VOL ISH_PU ISH_PD IOZ |VOD| MAX14942 only RXD to GNDA, IOUT = -4mA MAX14941 only, DEM to GNDB, IOUT = -4mA VDDA 0.4 VDDB 0.4 V RXD to GNDA, IOUT = 4mA 0.40 MAX14941 only, DEM to GNDB, IOUT = 4mA 0.40 MAX14942 only, SBA to GNDA, IOUT = 4mA 0.45 0V ≤ VRXD ≤ VDDA, RE = low -42 MAX14941 only, 0V ≤ VDEM ≤ VDDB, DE = high, PV = high -42 +40 MAX14941 only, 0V ≤ VDEM ≤ VDDB, DE = low, PV = high +40 MAX14942 only, 0V ≤ VSBA ≤ VDDA, side B is powered and working +60 -1 RL = 54Ω, TXD = high or low, Figure 1a 2.1 RL = 100Ω, TXD = high or low, Figure 1a 2.9 -7V ≤ VCM ≤ +12V, Figure 1b 1.5 V mA 0V ≤ VRXD ≤ VDDA, RE = low 0V ≤ VRXD ≤ VDDA, RE = high µA +1 mA µA V 5 Maxim Integrated │ 3 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection DC Electrical Characteristics (continued) (VDDA – VGNDA = 1.71V to 5.5V, VDDB – VGNDB = 4.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA – VGNDA = 3.3V, VDDB – VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3) PARAMETER Differential Driver Peak-to-Peak Output SYMBOL VODPP Change in Magnitude of Differential Driver Output Voltage ΔVOD Driver Common Mode Output Voltage VOC Change in Magnitude of Common-Mode Voltage Driver Short-Circuit Output Current Driver Short-Circuit Foldback Output Current ΔVOC IOSD IOSDF CONDITIONS MIN TYP MAX UNITS Figure 2 (Note 5) 4.0 6.8 V RL = 54Ω (Note 6) -0.2 +0.2 V 3 V +0.2 V RL = 54Ω, Figure 1a RL = 54Ω, Figure 1a (Note 6) 1.8 -0.2 GNDB ≤ VOUT ≤ +12V, output low (Note 7) +250 mA -7V ≤ VOUT ≤ VDDB, output high (Note 7) -250 (VDDB – 1V) ≤ VOUT ≤ +12V, output low (Note 7, 8) +15 mA -7V ≤ VOUT ≤ +1V, output high (Note 7, 8) -15 RECEIVER Input Current (A and B) IA, IB DE = low, VDDB = GNDB or 5.5V Receiver Differential Threshold Voltage VTH -7V ≤ VCM ≤ +12V Receiver Input Hysteresis ΔVTH Receiver Input Resistance RIN Differential Input Capacitance CA,B VIN = +12V VIN = -7V +250 -200 -200 VCM = 0V -7V ≤ VCM ≤ +12V, DE = low Measured between A and B, DE = RE = low at 6MHz -125 15 48 -50 µA mV mV kΩ 8 pF +160 °C 15 °C PROTECTION Thermal-Shutdown Threshold TSHDN Thermal-Shutdown Hysteresis THYST ESD Protection (A and B Pins to GNDB) ESD Protection (All Other Pins) www.maximintegrated.com Temperature Rising Human Body Model ±35 IEC 61000-4-2 Air Gap Discharge ±12 IEC 61000-4-2 Contact Discharge ±10 Human Body Model ±4 kV kV Maxim Integrated │ 4 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Switching Electrical Characteristics (VDDA – VGNDA = 1.71V to 5.5V, VDDB – VGNDB = 4.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA – VGNDA = 3.3V, VDDB – VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C.) (Note 8) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DYNAMIC Common Mode Transient Immunity CMTI Glitch Rejection (Note 9) TXD, DE, RXD 35 10 17 kV/μs 29 ns RL = 54Ω, CL = 50pF, Figure 3 and tDPLH, tDPHL Figure 4 68 ns tDSKEW RL = 54Ω, CL = 50pF, Figure 3 and Figure 4 6 ns tLH, tHL RL = 54Ω, CL = 50pF, Figure 3 and 4 15 ns DRIVER Driver Propagation Delay Differential Driver Output Skew |tDPLH - tDPHL| Driver Differential Output Rise or Fall Time Maximum Data Rate DRMAX 20 Mbps Driver Enable to Output High tDZH RL = 500Ω, CL = 50pF, Figure 5 88 ns Driver Enable to Output Low tDZL tDLZ tDHZ RL = 500Ω, CL = 50pF, Figure 6 88 ns RL = 500Ω, CL = 50pF, Figure 6 80 ns RL = 500Ω, CL = 50pF, Figure 5 80 ns 68 ns 6 ns Driver Disable Time from Low Driver Disable Time from High RECEIVER Receiver Propagation Delay tRPLH, tRPHL CL = 15pF, Figure 7 and 8 (Note 10) Receiver Output Skew |tRPLH - tRPHL| tRSKEW Maximum Data Rate DRMAX Receiver Enable to Output High CL = 15pF, Figure 7 and 8 (Note 10) 20 Mbps Receiver Enable to Output Low tRZL RL = 1kΩ, CL = 15pF, S2 closed, Figure 9 RL = 1kΩ, CL = 15pF, S1 closed, Figure 9 Receiver Disable Time From Low tRLZ RL = 1kΩ, CL = 15pF, S1 closed, Figure 9 20 ns Receiver Disable Time From High tRHZ RL = 1kΩ, CL = 15pF, S2 closed, Figure 9 20 ns tRZH 20 ns 30 ns Note 2: All devices are 100% production tested at TA = +25°C. 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: VODPP is the difference in VOD when TXD is high and when TXD is low. Note 6: ΔVOD and ΔVOC 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: Not production tested. Guaranteed by design. Note 9: 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. ΔVCM = 1kV. Note 10: Capacitive load includes test probe and fixture capacitance. www.maximintegrated.com Maxim Integrated │ 5 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Insulation Characteristics PARAMETER SYMBOL Partial Discharge Test Voltage VPR VALUE UNITS Method B1 = VIORM x 1.875 (t = 1s, partial discharge < 5pC) CONDITIONS 2250 VP 1200 V Maximum Repetitive Peak Isolation Voltage VIORM (Note 11) Maximum Working Isolation Voltage VIOWM (Note 11) 848 VRMS Maximum Transient Isolation Voltage VIOTM VISO t = 1s 8400 VP t = 60s, f = 60Hz (Note 11, 12) 5000 VISOM RS IEC 61000-4-5, 1.2/50µs 10 VRMS kV TA = +150°C, VIO = 500V > 109 Ω Maximum Withstand Isolation Voltage Maximum Surge Isolation Voltage Insulation Resistance Barrier Capacitance Input-to-Output Minimum Creepage Distance CIO CPG f = 1MHz Wide SOIC 2 8 pF mm Minimum Clearance Distance CLR Wide SOIC 8 mm Internal Clearance Comparative Tracking Resistance Index Distance through insulation Material Group II (IEC 60112) 0.015 575 mm CTI Climatic Category 40/125/21 Pollution Degree (DIN VDE 0110, Table 1) 2 Note 11: VIORM, VIOWM, and VISO are defined by the IEC 60747-5-5 standard. Note 12: Product is qualified at VISO for 60 seconds. 100% production tested at 120% of VISO for 1 second. Safety Regulatory Approvals (Pending) UL The MAX14941/MAX14942 is certified under UL1577. For more details, see File E351759. Rate up to 5000VRMS isolation voltage for basic insulation. cUL Pending VDE Pending TUV Pending 375Ω A A RL 2 VOD VOD RL 2 + VCM - VOC B B (a) 60Ω 375Ω (b) Figure 1. Driver DC Test Load www.maximintegrated.com Maxim Integrated │ 6 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection VDDB VDDA 195I A TXD 110I VOD B 195I GNDA GNDB Figure 2. VODPP Swing Under Profibus Equivalent Load Test A TXD B VOD RL CL GNDA Figure 3. Driver Timing Test Circuit f = 1MHz, tLH P 3ns, tHL P 3ns VDDA 50% TXD 50% GNDA 1/2 VO tDPHL tDPLH B A 1/2 VO VO VDIFF = VA - VB VO 80% 80% VDIFF 0 20% 20% tLH -VO tHL tDSKEW = |tDPLH - tDPHL| Figure 4. Driver Propagation Delays www.maximintegrated.com Maxim Integrated │ 7 MAX14941/MAX14942 A GNDA OR VDDA TXD D B DE 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection S1 VDDA OUT CL 50pF DE RL = 500I 50% 250mV OUT GENERATOR 50% GNDB 50I GNDA tDZH tDHZ VOH GNDB GNDA Figure 5. Driver Enable and Disable Times (tDHZ, tDZH) VDDB GNDA OR VDDA A TXD OUT D B DE GENERATOR RL = 500I S1 CL = 50pF GNDB 50I GNDA VDDA DE 50% GNDA tDZL tDLZ 50% OUT VDDB 250mV VOL Figure 6. Driver Enable and Disable Times (tDZL, tDLZ) A ATE R VID RECEIVER OUTPUT B Figure 7. Receiver Propagation Delay Test Circuit www.maximintegrated.com Maxim Integrated │ 8 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection f = 1MHz, tLH P 3ns, tHL P 3ns A 1V B -1V tRPHL tRPLH VDDA 2 RXD VOH VDDA 2 VOL tRSKEW = |tRPHL - tRPLH| Figure 8. 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 9. Receiver Enable and Disable Times www.maximintegrated.com Maxim Integrated │ 9 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Typical Operating Characteristics (VDDA – VGNDA = 3.3V, VDDB – VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C, unless otherwise noted.) VDDA SUPPLY CURRENT vs. TEMPERATURE 8 toc01 14 7 30 4 SINK CURRENT (mA) 5 8 6 3 4 2 1 2 NO LOAD NO SWITCHING -45 -30 -15 0 15 30 45 60 75 0 90 105 -45 -30 -15 0 15 30 45 60 75 toc04 5.5 DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE toc05 15 3.5 3.0 2.5 2.0 10 120Ω LOAD 54Ω LOAD 1.5 1.0 5 2.5 3.0 0.0 3.5 -45 -30 -15 OUTPUT HIGH VOLTAGE (V) 20 DRIVER OUTPUT CURRENT vs OUTPUT HIGH VOLTAGE toc07 30 25 PROPAGATION DELAY (ns) OUTPUT CURRENT (mA) 0 -40 -60 -80 -100 15 30 45 60 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 OUTPUT HIGH VOLTAGE (V) www.maximintegrated.com 75 4 5 2.5 3.0 3.5 toc6 80 60 40 0 1 2 3 toc08 50 45 tPDHL 15 tPDLH 10 RL = 54Ω CL = 50pF -45 -30 -15 0 15 30 45 60 TEMPERATURE (°C) 4 5 6 7 8 9 10 11 12 OUTPUT LOW VOLTAGE (V) 20 0 2.0 100 0 90 105 TRANSMITTER PROPAGATION DELAY vs. TEMPERATURE 5 -120 1.5 DRIVER OUTPUT CURRENT vs OUTPUT LOW VOLTAGE TEMPERATURE (°C) -20 -140 0 PROPAGATION DELAY (ns) 2.0 1.0 20 0.5 1.5 0.5 140 OUTPUT CURRENT (mA) 20 1.0 0.0 120 No load 4.0 0.5 10 OUTPUT LOW VOLTAGE (V) 4.5 VOD (V) SOURCE CURRENT (mA) 25 0.0 15 0 90 105 5.0 0 20 TEMPERATURE (°C) RECEIVER OUTPUT CURRENT vs OUTPUT HIGH VOLTAGE toc03 5 NO LOAD NO SWITCHING TEMPERATURE (°C) 30 RECEIVER OUTPUT CURRENT vs OUTPUT LOW VOLTAGE 25 10 IDDB (mA) IDDA (mA) toc02 12 6 0 VDDB SUPPLY CURRENT vs. TEMPERATURE 75 90 105 RECEIVER PROPAGATION DELAY vs. TEMPERATURE toc09 CL = 15pF 40 35 tRPLH 30 25 20 15 tRPHL 10 5 0 -45 -30 -15 0 15 30 45 60 75 90 105 TEMPERATURE (°C) Maxim Integrated │ 10 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Typical Operating Characteristics (continued) (VDDA – VGNDA = 3.3V, VDDB – VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C, unless otherwise noted.) DRIVER ENABLE/DISABLE DELAY vs. TEMPERATURE 80 DRIVER PROPAGATION DELAY toc10 RL = 54Ω CL = 50pF ENABLE/DISABLE DELAY (ns) 70 toc11 TXD 2V/div 60 0V 50 40 A 1V/div tDHZ tDZL 30 20 B 1V/div 10 0 tDLZ -45 -30 -15 0 15 tDZH 30 45 60 75 10ns/div 90 105 TEMPERATURE (°C) RECEIVER PROPAGATION DELAY toc12 VDDA SUPPLY CURRENT vs. DATA RATE 8 CL = 15pF toc13 7 RXD 2V/div 6 0V IDDA (mA) 5 A 1V/div 4 3 2 B 1V/div 1 0 10ns/div 0 5 10 15 20 DATA RATE (Mbps) VDDB SUPPLY CURRENT vs. DATA RATE 80 70 toc14 54Ω LOAD 60 IDDB (mA) 50 40 120Ω LOAD 30 20 NO LOAD 10 0 www.maximintegrated.com 0 5 10 15 DATA RATE (Mbps) 20 Maxim Integrated │ 11 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Pin Configuration TOP VIEW + 16 VDDB VDDA 1 15 GNDB GNDA 2 RXD 3 13 B RE 4 13 B 5 12 A DE 5 12 A TXD 6 11 VLDO TXD 6 11 VLDO PV 7 10 DEM SBA 7 10 N.C. GNDA 8 9 GNDA 8 9 VDDA 1 GNDA 2 RXD 3 RE 4 DE + MAX14941 14 N.C. GNDB 16 VDDB 15 GNDB MAX14942 14 N.C. GNDB WIDE SOIC Pin Description PIN MAX14941 MAX14942 NAME REFERENCE FUNCTION 1 1 VDDA GNDA UART/Logic-Side Power Input. Bypass VDDA to GNDA with both 0.1µF and 1µF capacitors as close to the device as possible. 2, 8 2, 8 GNDA - UART/Logic-Side Ground. GNDA is the ground reference for digital signals. 3 3 RXD GNDA Receiver Data Output. Drive RE low to enable RXD. With RE low, RXD is high when (VA – VB) > -50mV and is low when (VA – VB) < -200mV. RXD is high when VDDB is less than VUVLOB. RXD is high impedance when RE is high. 4 4 RE GNDA Receiver Output Enable. Driver 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 4.5µA pull-down to GNDA. 5 5 DE GNDA Driver Output Enable. Drive DE high to enable bus driver outputs A and B. Drive DE low or connect to GNDA to disable A and B. A and B are high impedance when DE is low. DE has an internal 4.5µA pull-down to GNDA. GNDA Driver Input. With DE high, a low on TXD forces the noninverting output (A) low and the inverting output (B) high. Similarly, a high on TXD forces the noninverting output high and the inverting output low. TXD has an internal 4.5µA pull-up to VDDA. 6 6 www.maximintegrated.com TXD Maxim Integrated │ 12 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Pin Description (continued) PIN MAX14941 MAX14942 NAME REFERENCE FUNCTION 7 - PV GNDA Power Valid Input. Hold PV low to disable the driver while the supplies stabilize. Pull PV high when power is stable to enable the driver. PV has an internal 4.5µA pull-up to VDDA. - 7 SBA GNDA Side B Active Indicator Output. SBA asserts low when side B is powered and working. SBA has an internal 5kΩ pull-up resistor to VDDA. 9, 15 9, 15 GNDB - Cable-Side Ground. GNDB is the ground reference for the internal LDO, the DEM output, and the Profibus/RS-485 bus signals. 10 - DEM GNDB Driver Enable Monitor Output. DEM is high when the transmitter is enabled. See the Function Tables for more information. 14 10, 14 N.C. - VLDO GNDB LDO Power Input. Connect a minimum voltage of 4.68V to VLDO to power the cable-side of the transceiver. Bypass VLDO to GNDB with both 0.1µF and 1µF capacitors as close to the device as possible. To disable the internal LDO, leave VLDO unconnected or connect to GNDB. 12 A GNDB Noninverting Receiver Input and Noninverting Driver Output 13 B GNDB Inverting Receiver Input and Inverting Driver Output GNDB Cable-Side Power Input/Isolated LDO Power Output. Bypass VDDB to GNDB with both 0.1µF and 1μF capacitor as close to the device as possible. 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. 11 11 12 13 16 No Connection. Not internally-connected. 16 www.maximintegrated.com VDDB Maxim Integrated │ 13 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Function Tables TRANSMITTING INPUTS OUTPUTS VDDA VDDB DE TXD PV** A B DEM** ≥ VUVLOA ≥ VUVLOB 1 X 0 High-Z High-Z 1 ≥ VUVLOA ≥ VUVLOB 1 1 1 1 0 1 ≥ VUVLOA ≥ VUVLOB 1 0 1 0 1 1 ≥ VUVLOA ≥ VUVLOB 0 X X High-Z High-Z 0 < VUVLOA ≥ VUVLOB X X X High-Z High-Z 0 ≥ VUVLOA < VUVLOB X X X High-Z High-Z 0 < VUVLOA < VUVLOB X X X High-Z High-Z 0 *Note: Drive DE low to disable the transmitter outputs. Drive DE high to enable the transmitter outputs. DE has an internal pull-down to GNDA. ** MAX14941 only, X = Don’t care RECEIVING INPUTS OUTPUTS VDDA VDDB RE (VA- VB) RXD ≥ VUVLOA ≥ VUVLOB 0 > -50mV 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 pull-down to GNDA. X = Don’t care SBA VDDA VDDB SBA < VUVLOA < VUVLOB High < VUVLOA ≥ VUVLOB High ≥ VUVLOA < VUVLOB High ≥ VUVLOA ≥ VUVLOB Low www.maximintegrated.com Maxim Integrated │ 14 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Detailed Description The MAX14941/MAX14942 isolated PROFIBUS-DP/ RS-485 transceivers provide 2500VRMS (60s) of galvanic isolation between the PROFIBUS-DP/RS-485 cableside of the transceiver and the UART-side. These devices allow fast (20Mbps) communication across an isolation barrier when a large potential exists between grounds on each side of the barrier. Isolation Data isolation is achieved using high-voltage capacitors that allow data transmission between the UART-side and the Profibus/RS-485 cable-side of the transceiver. Integrated LDO The devices include an internal low-dropout regulator with a set 5V (typ) output that is used to power the cable-side of the IC. The output of the LDO is VDDB. In addition to powering the transceiver, VDDB can source up to 10mA, allowing external termination resistors to be powered without the need for an external regulator. The LDO has a 300mA (typ) current limit. If the LDO is unused, connect VLDO to GNDB and apply +5V directly to VDDB. True Fail-Safe The MAX14941/MAX14942 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 -50mV and -200mV. If the differential receiver input voltage (VA – VB) is greater than or equal to -50mV, 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 MAX14941/MAX14942, 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 bus contention. The first, a foldback mode current limit on the output stage, provides immediate protection against short circuits over the entire common-mode voltage range. The second, a thermalshutdown circuit, forces the driver outputs into a high-impedance state if the die temperature exceeds +160°C (typ). Thermal Shutdown The devices are protected from overtemperature damage by integrated thermal shutdown circuitry. When the junction temperature (TJ) exceeds +160°C (typ), the driver outputs go high-impedance. The device resumes normal operation when TJ falls below +145°C (typ). Applications Information 128 Transceivers on the Bus The standard RS-485 receiver input impedance is one unit load. A standard driver can drive up to 32 unit-loads. The MAX14941/MAX14942 transceivers have a ¼-unit load receiver, which allows 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 MAX14941/MAX14942 transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figure 10 and Figure 11 show typical network application circuits. To minimize reflections, the bus should be terminated at both ends in its characteristics impedance, and stub lengths off the main line should be kept as short as possible. Maxim Integrated │ 15 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection RXD RE TXD DE A RS-485 TRANSCEIVER RS-485 TRANSCEIVER MAX14941/MAX14942 A 120Ω 120Ω B B B A B RS-485 TRANSCEIVER RXD RE TXD DE A RS-485 TRANSCEIVER MAX14941 MAX14942 INTEGRATED ISOLATION BARRIER DE TXD RE RXD DE TXD RE RXD Figure 10. Typical Isolated Half-Duplex RS-485 Application VLDO VLDO 0.1µF 1µF 0.1µF 1µF 1 2 LDO RXD RE TXD DE VDDB VDDB 2 2 A 220Ω B 2 1µF 3 390Ω 390Ω PROFIBUS A LINE 3 A 220Ω B PROFIBUS B LINE 390Ω 390Ω 2 1 0.1µF 0.1µF 1µF 3 LDO 0.1µF 3 MAX14941 MAX14942 RS-485 TRANSCEIVER 1 2 MAX14941 MAX14942 RS-485 TRANSCEIVER VDDA 1µF 3 VDDA 1µF 0.1µF RXD 4 4 RE TXD DE 3 4 Figure 11. Typical Isolated Profibus Application www.maximintegrated.com Maxim Integrated │ 16 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Profibus Termination These devices are designed for driving PROFIBUS DP terminated networks. The driver maintains 2.1V (min) when driving a worst-case loading condition of two standard 220Ω termination resistors with 390Ω pullups/ pulldowns. 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 will defeat 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. Route important signal lines close to the ground plane to minimize possible external influences. On the cable-side of the MAX14941/MAX14942, it is good practice to have the bus connectors and termination resistor as close as possible to the A and B pins. Extended ESD Protection 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 MAX14941/MAX14942 have extra protection against static electricity to both the UART-side and cable-side ground references. The ESD structures withstand high-ESD events during normal operation and when powered down. After an ESD event, the devices keep working without latch-up or damage. 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 12 shows the HBM test model, while Figure 13 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 into the test device through a 1.5kΩ resistor. 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 MAX14941/ MAX14942 help in designing equipment to meet IEC 61000-4-2 without the need for additional ESD protection components. 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 14 shows the IEC 61000-4-2 model and Figure 15 shows the current waveform for IEC 61000-4-2 ESD Contact Discharge Test. Bypass VDDA to GNDA and bypass VDDB and VLDO to GNDB with 0.1μF and 1μF capacitors to ensure maximum ESD protection. ESD protection can be tested in various ways. The transmitter outputs and receiver inputs of the MAX14941/ MAX14942 are characterized for protection to the cableside ground (GNDB) to the following limits: ●● ±35kV HBM ●● ±12kV using the Air-Gap Discharge method specified in IEC 61000-4-2 ●● ±10kV using the Contact Discharge method specified in IEC 61000-4-2 www.maximintegrated.com Maxim Integrated │ 17 MAX14941/MAX14942 RC 1MΩ CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection RD 1500Ω IP 100% 90% DISCHARGE RESISTANCE STORAGE CAPACITOR Ir AMPS DEVICE UNDER TEST 36.8% 10% 0 0 Figure 12. Human Body ESD Test Model CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 150pF TIME tDL CURRENT WAVEFORM Figure 13. Human Body Current Waveform RD 330Ω I 100% 90% DISCHARGE RESISTANCE STORAGE CAPACITOR tRL IPEAK RC 50MΩ TO 100MΩ PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) DEVICE UNDER TEST 10% tr = 0.7ns TO 1ns t 30ns 60ns Figure 14. IEC 61000-4-2 ESD Test Model www.maximintegrated.com Figure 15. IEC 61000-4-2 ESD Generator Current Waveform Maxim Integrated │ 18 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Typical Application Circuit VLDO VDDA (PV) SBA* MAX14941 MAX14942 VDDB LDO A RS-485 TRANSCEIVER RXD RE µC TXD DE B (DEM) GNDA () MAX14941 only * MAX14942 only www.maximintegrated.com GNDB ISOLATION BARRIER Maxim Integrated │ 19 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Ordering Information/Selector Guide DEM PV SBA TEMP RANGE PIN-PACKAGE MAX14941GWE+ √ √ - -40°C to +105°C 16 SOIC (W) MAX14941GWE+T √ √ - -40°C to +105°C 16 SOIC (W) MAX14942GWE+ - - √ -40°C to +105°C 16 SOIC (W) MAX14942GWE+T - - √ -40°C to +105°C 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+9 21-0042 90-0107 Maxim Integrated │ 20 MAX14941/MAX14942 5kV Isolated 20Mbps Half-Duplex PROFIBUS/ RS-485 Transceivers with ±35kV ESD Protection Revision History REVISION NUMBER REVISION DATE 0 11/15 DESCRIPTION Initial release PAGES CHANGED — 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. © 2015 Maxim Integrated Products, Inc. │ 21