MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers General Description Features The MAX13442E/MAX13444E are fault-protected RS-485 and J1708 transceivers that feature 80V protection from signal faults on communication bus lines. The MAX13442E/MAX13444E feature a reduced slew-rate driver that minimizes EMI and reflections, allowing errorfree transmission up to 250kbps. The MAX13443E driver can transmit up to 10Mbps. The high-speed MAX13443E RS-485 transceiver features 60V protection from signal faults on communication bus lines. These transceivers feature foldback current limit. Each device contains one differential line driver with three-state output and one differential line receiver with three-state input. The 1/4-unitload receiver input impedance allows up to 128 transceivers on a single bus. The devices operate from a 5V supply. True fail-safe inputs guarantee a logic-high receiver output when the receiver inputs are open, shorted, or connected to an idle data line. 15kV ESD Protection 80V Fault Protection (60V MAX13443E) Guaranteed 10Mbps Data Rate (MAX13443E) Hot-Swappable for Telecom Applications True Fail-Safe Receiver Inputs Enhanced Slew-Rate-Limiting Facilitates Error-Free Data Transmission (MAX13442E/MAX13444E) Allow Up to 128 Transceivers on the Bus -7V to +12V Common-Mode Input Range 6mA FoldBack Current Limit Industry-Standard Pinout Applications RS-422/RS-485 Communications Truck and Trailer Applications Industrial Networks Hot-swap circuitry eliminates false transitions on the data bus during circuit initialization or connection to a live backplane. Short-circuit current-limiting and thermal-shutdown circuitry protect the driver against excessive power dissipation, and on-chip 15kV ESD protection eliminates costly external protection devices. Ordering Information PART The MAX13442E/MAX13443E/MAX13444E are available in an 8-pin SO package and are specified over the automotive temperature range. MAX13442E RS-485 MAX13443E RS-485 10 60 MAX13444E J1708 0.25 80 8 SO MAX13443EASA+ -40C to +125C 8 SO MAX13444EASA/V+T -40C to +125C 8 SO RECEIVER/DRIVER ENABLE Yes TRANSCEIVERS ON BUS 128 Yes Yes 128 Yes Yes Yes 128 Yes (only RE) Pin Configurations and Typical Operating Circuits TOP VIEW RO 1 + R RE 2 DE 3 DI 4 D SO RO 1 8 VCC 7 B RE 2 6 A DE 5 GND + R 8 VCC 7 B RT 6 A 5 GND 3 DI 4 D SO DE MAX13442E MAX13443E Pin Configurations and Typical Operating Circuits continued at end of data sheet. 19-3898; Rev 3; 3/11 PIN-PACKAGE -40C to +125C DATA RATE FAULT LOW-POWER (Mbps) PROTECTION (V) SHUTDOWN 0.25 80 Yes TYPE TEMP RANGE MAX13442EASA+ +Denotes lead(Pb)-free/RoHS-compliant package. /V denotes an automotive qualified part. T = Tape and reel. Selector Guide PART Telecommunications Systems Automotive Applications HVAC Controls RT D B A DI RO R RE HOT SWAP Yes MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Absolute Maximum Ratings (Voltages referenced to GND.) VCC.........................................................................................+7V RE, DE, DE, DI, TXD................................ -0.3V to (VCC + 0.3V) A, B (Note 1) (MAX13442E/MAX13444E)...........................80V A, B (Note 1) (MAX13443E).................................................60V RO............................................................. -0.3V to (VCC + 0.3V) Short-Circuit Duration (RO, A, B)...............................Continuous Continuous Power Dissipation (TA = +70C) SO (derate 7.6mW/C above +70C)...........................606mW Operating Temperature Range.......................... -40C to +125C Storage Temperature Range............................. -65C to +150C Junction Temperature.......................................................+150C Lead Temperature (soldering, 10s).................................. +300C Soldering Temperature (reflow)........................................+260C Note 1: During normal operation, a termination resistor must be connected between A and B in order to guarantee overvoltage protection up to the absolute maximum rating of this device. When not in operation, these devices can withstand fault voltages up to the maximum rating without a termination resistor and will not be damaged. 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 2) SO Junction-to-Ambient Thermal Resistance (JA).........132C/W Junction-to-Case Thermal Resistance (JC)................38C/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 (VCC = +4.75V to +5.25V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DRIVER Differential Driver Output Change in Magnitude of Differential Output Voltage Driver Common-Mode Output Voltage Change in Magnitude of Common-Mode Voltage VOD VOD VOC DVOC Figure 1, RL = 100 2 VCC Figure 1, RL = 54 1.5 VCC Figure 1, RL = 100 or 54 (Note 3) Figure 1, RL = 100 or 54 VCC/2 Figure 1, RL = 100 or 54 (Note 3) (MAX13442E/MAX13443E) V 0.2 V 3 V 0.2 V DRIVER LOGIC Driver-Input High Voltage VDIH Driver-Input Low Voltage VDIL 0.8 V Driver-Input Current IDIN 2 A Driver Short-Circuit Output Current (Note 4) IOSD Driver Short-Circuit Foldback Output Current IOSDF Driver-Limit Short-Circuit Foldback Output Current IOSDL www.maximintegrated.com 2 0V VOUT +12V +350 -7V VOUT VCC -350 (VCC - 1V) VOUT +12V (Note 4) +25 -7V VOUT +1V (Note 4) VOUT +20V, RL = 100 VOUT -15V, RL = 100 V -25 +6 -6 mA mA mA Maxim Integrated 2 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers DC Electrical Characteristics (continued) (VCC = +4.75V to +5.25V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS RECEIVER Input Current Receiver-Differential Threshold Voltage Receiver-Input Hysteresis IA,B VTH A, B receive mode VCC = GND, VA, B = 12V 250 VA, B = -7V -150 VA, B = 80V -7V VCM +12V -200 VTH A 6 mA -50 mV 25 mV RECEIVER LOGIC Output-High Voltage VOH Figure 2, IOH = -1.6mA VCC - 0.6 V Output-Low Voltage VOL Figure 2, IOL = 1mA 0.4 V Three-State Output Current at Receiver IOZR 0V VA, B VCC 1 A Receiver Input Resistance RIN -7V VCM +12V Receiver Output Short-Circuit Current IOSR 0V VRO VCC VCIH DE, DE, RE 48 k 95 mA CONTROL Control-Input High Voltage Input-Current Latch During First Rising Edge IIN 2 DE, RE V 90 A SUPPLY CURRENT Normal Operation Supply Current in Shutdown Mode Supply Current with Output Shorted to 60V www.maximintegrated.com ICC ISHDN ISHRT No load, DI = VCC or GND DE = VCC, RE = GND (MAX13442E) (DE = RE = GND) (MAX13444E) 30 (DE = VCC, RE = GND) (MAX13443E) 10 mA DE = GND, RE = VCC (MAX13442E/MAX13443E) 20 DE = GND, RE = VCC, TA = +25C (MAX13442E/MAX13443E) 10 DE = RE = VCC (MAX13444E) 100 DE = RE = VCC, TA = +25C (MAX13444E) 10 DE = GND, RE = GND, no load output in three-state (MAX13443E) 15 A mA Maxim Integrated 3 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Protection Specifications (VCC = +4.75V to +5.25V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) PARAMETER SYMBOL CONDITIONS MAX13442E/ A, B; RSOURCE = 0, MAX13444E RL = 54 MAX13443E Overvoltage Protection ESD Protection A, B MIN TYP MAX 80 UNITS V 60 15 Human Body Model kV Switching Characteristics (MAX13442E/MAX13444E) (VCC = +4.75V to +5.25V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) PARAMETER SYMBOL CONDITIONS Driver Propagation Delay tPLHA, tPLHB Figure 3, RL = 54, CL = 50pF (MAX13442E) Driver Differential Propagation Delay tDPLH, tDPHL RL = 54, CL = 50pF, Figure 4 Driver Differential Output Transition Time tLH,tHL RL = 54, CL = 50pF, Figure 4 Driver Output Skew Differential Driver Output Skew MIN RDIFF = 60, CDIFF = 100pF (MAX13444E) 200 RL = 54, CL = 50pF, tSKEWAB, t = |tPLHA - tPHLB|, tSKEWBA SKEWAB tSKEWBA = |tPLHB - tPHLA| tDSKEW RL = 54, CL = 50pF, tDSKEW = |tDPLH - tDPHL| TYP MAX UNITS 2000 ns 2000 ns 2000 ns 350 ns 200 ns Maximum Data Rate fMAX 250 kbps Driver Enable Time to Output High tPDZH RL = 500, CL = 50pF, Figure 5 2000 ns Driver Disable Time from Output High tPDHZ RL = 500, CL = 50pF, Figure 5 2000 ns Driver Enable Time from Shutdown to Output High tPDHS RL = 500, CL = 50pF, Figure 5 4.2 s Driver Enable Time to Output Low tPDZL RL = 500, CL = 50pF, Figure 6 2000 ns Driver Disable Time from Output Low tPDLZ RL = 500, CL = 50pF, Figure 6 2000 ns Driver Enable Time from Shutdown to Output Low tPDLS RL = 500, CL = 50pF, Figure 6 4.2 s Driver Time to Shutdown tSHDN RL = 500, CL = 50pF 800 ns Receiver Propagation Delay tRPLH, tRPHL CL = 20pF, VID = 2V, VCM = 0V, Figure 7 2000 ns Receiver Output Skew tRSKEW CL = 20pF, tRSKEW = |tRPLH - tRPHL| 200 ns Receiver Enable Time to Output High tRPZH RL = 1k, CL = 20pF, Figure 8 2000 ns Receiver Disable Time from Output High tRPHZ RL = 1k, CL = 20pF, Figure 8 2000 ns 4.2 s Receiver Wake Time from Shutdown tRPWAKE RL = 1k, CL = 20pF, Figure 8 Receiver Enable Time to Output Low tRPZL RL = 1k, CL = 20pF, Figure 8 2000 ns Receiver Disable Time from Output Low tRPLZ RL = 1k, CL = 20pF, Figure 8 2000 ns Receiver Time to Shutdown tSHDN RL = 500, CL = 50pF 800 ns www.maximintegrated.com Maxim Integrated 4 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Switching Characteristics (MAX13443E) (VCC = +4.75V to +5.25V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) PARAMETER SYMBOL MAX UNITS RL = 27, CL = 50pF, Figure 3 60 ns tDPLH, tDPHL RL = 54, CL = 50pF, Figure 4 60 ns tLH,tHL RL = 54, CL = 50pF, Figure 4 25 ns 10 ns 10 ns Driver Propagation Delay tPLHA, tPLHB Driver Differential Propagation Delay Driver Differential Output Transition Time Driver Output Skew Differential Driver Output Skew CONDITIONS MIN R = 54, CL = 50pF, tSKEWAB, L t = |tPLHA - tPHLB|, tSKEWBA SKEWAB tSKEWBA = |tPLHB - tPHLA| tDSKEW RL = 54, CL = 50pF, tDSKEW = |tDPLH - tDPHL| TYP Maximum Data Rate fMAX Driver Enable Time to Output High tPDZH RL = 500, CL = 50pF, Figure 5 1200 ns Driver Disable Time from Output High tPDHZ RL = 500, CL = 50pF, Figure 5 1200 ns Driver Enable Time from Shutdown to Output High tPDHS RL = 500, CL = 50pF, Figure 5 4.2 s Driver Enable Time to Output Low tPDZL RL = 500, CL = 50pF, Figure 6 1200 ns Driver Disable Time from Output Low tPDLZ RL = 500, CL = 50pF, Figure 6 1200 ns Driver Enable Time from Shutdown to Output Low tPDLS RL = 500, CL = 50pF, Figure 6 4.2 Fs Driver Time to Shutdown tSHDN RL = 500, CL = 50pF, Figure 6 800 ns Receiver Propagation Delay tRPLH, tRPHL CL = 20pF, VID = 2V, VCM = 0V, Figure 7 85 ns CL = 20pF, tRSKEW = |tRPLH - tRPHL| 15 ns tRPZH RL = 1k, CL = 20pF, Figure 8 400 ns tRPHZ RL = 1k, CL = 20pF, Figure 8 400 ns tRPWAKE RL = 1k, CL = 20pF, Figure 8 4.2 s Receiver Output Skew Receiver Enable Time to Output High Receiver Disable Time from Output High Receiver Wake Time from Shutdown tRSKEW 10 Mbps Receiver Enable Wake Time from Shutdown tRPSH RL = 1k, CL = 20pF, Figure 8 400 ns Receiver Disable Time from Output Low tRPLZ RL = 1k, CL = 20pF, Figure 8 400 ns Receiver Time to Shutdown tSHDN RL = 500, CL = 50pF 800 ns Note 3: VOD and VOC are the changes in VOD and VOC, respectively, when the DI input changes state. Note 4: The short-circuit output current applies to peak current just before foldback current limiting. The short-circuit foldback output current applies during current limiting to allow a recovery from bus contention. www.maximintegrated.com Maxim Integrated 5 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Typical Operating Characteristics (VCC = +5V, TA = +25C, unless otherwise noted.) DRIVER DISABLED, RECEIVER ENABLED 2 16 12 1 8 4 MAX13443E 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 0 DRIVER DISABLED, RECEIVER ENABLED MAX13442E/MAX13444E 25 20 15 10 5 0 RECEIVER OUTPUT VOLTAGE (V) MAX13442-4E toc03 40 60 25 20 15 10 5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 OUTPUT LOW VOLTAGE (V) VOH, IOUT = 10mA 2.5 2.0 1.5 VOL, IOUT = -10mA -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C) www.maximintegrated.com 80 100 120 MAX13442-4E toc05 30 DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE 3.0 0 20 RECEIVER OUTPUT VOLTAGE vs. TEMPERATURE 3.5 0.5 0 OUTPUT LOW VOLTAGE (V) 4.5 1.0 -40 -20 35 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.0 4.0 0.00001 40 140 DRIVER OUTPUT CURRENT (mA) 0 0.0001 TEMPERATURE (C) RECEIVER OUTPUT CURRENT (mA) MAX13442-4E toc04 30 0.001 RECEIVER OUTPUT CURRENT vs. OUTPUT-HIGH VOLTAGE MAX13442-4E toc06 RECEIVER OUTPUT CURRENT (mA) 35 0.01 TEMPERATURE (C) RECEIVER OUTPUT CURRENT vs. OUTPUT-LOW VOLTAGE 40 MAX13442E DI = DE = GND RE = VCC 0.1 0.000001 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C) 1 RL = 54 MAX13442E DI = GND, DE = VCC, VOLTAGE APPLIED TO OUTPUT A 120 100 MAX13442-4E toc07 3 DRIVER AND RECEIVER ENABLED 10 SHUTDOWN SUPPLY CURRENT (A) 4 24 20 SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE NO-LOAD SUPPLY CURRENT vs. TEMPERATURE MAX13442-4E toc02 DRIVER AND RECEIVER ENABLED SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 5 MAX13442-4E toc01 6 NO-LOAD SUPPLY CURRENT vs. TEMPERATURE 80 60 40 20 0 10 20 30 40 50 60 70 80 DIFFERENTIAL OUTPUT VOLTAGE (V) Maxim Integrated 6 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Typical Operating Characteristics (continued) (VCC = +5V, TA = +25C, unless otherwise noted.) MAX13442E DI = GND, DE = VCC, VOLTAGE APPLIED TO OUTPUT B 70 60 50 40 30 20 10 0 -80 -65 -50 -35 -20 3.0 2.0 RL = 54 1.5 1.0 0.5 0 -5 RL = 100 2.5 MAX13442E -40 -25 -10 5 20 35 50 65 80 95 110 125 DIFFERENTIAL OUTPUT VOLTAGE (V) TEMPERATURE (C) DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE 3.0 MAX13442-4E toc10 RL = 100 2.5 2.0 A, B CURRENT (A) DIFFERENTIAL OUTPUT VOLTAGE (V) 3.5 RL = 54 1.5 1.0 0.5 0 MAX13443E -40 -25 -10 5 20 35 50 65 80 95 110 125 A, B CURRENT vs. A, B VOLTAGE (TO GROUND) 3200 2800 2400 2000 1600 1200 800 400 0 -400 -800 -1200 -1600 -2000 MAX13442-4E toc11 80 3.5 MAX13442-4E toc09 RL = 54 DIFFERENTIAL OUTPUT VOLTAGE (V) 90 MAX13442-4E toc08 DRIVER OUTPUT CURRENT (mA) 100 DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE DRIVER DISABLED, RECEIVER ENABLED NO LOAD RL = 54 MAX13442E -80 -60 TEMPERATURE (C) -40 -20 0 20 40 60 80 A, B VOLTAGE (V) 2000 1600 MAX13442-4E toc12 A, B CURRENT vs. A, B VOLTAGE (TO GROUND) DRIVER DISABLED, RECEIVER ENABLED A, B CURRENT (A) 1200 800 400 0 NO LOAD -400 -800 RL = 54 -1200 -1600 -2000 MAX13443E -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 A, B VOLTAGE (V) www.maximintegrated.com Maxim Integrated 7 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Test Circuits and Waveforms RL 2 A DI VOD D B RL VCC VOC 2 Figure 1. Driver VOD and VOC A VID RO R B 0 VOL IOL (+) VOH IOH (-) Figure 2. Receiver VOH and VOL 3V VOM A DI GENERATOR (NOTE 5) S1 B CL = 50pF (NOTE 6) VCC VOM = 1.5V 1.5V 0V tPLHA OUT D 50 DI RL 2 tPHLA VOH VOM A VOM VOL tPHLB VOH + VOL 1.5V 2 tPLHB VOH B VOM VOM VOL Figure 3. Driver Propagation Times 3V DI GENERATOR (NOTE 5) 50 A D RL B 0V OUT (A-B) CL = 50pF (NOTE 6) tDPHL tDPLH VCC CL 1.5V 1.5V DI CL 50% 10% tLH 90% 90% 2.0V 50% 10% -2.0V tHL Figure 4. Driver Differential Output Delay and Transition Times www.maximintegrated.com Maxim Integrated 8 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Test Circuits and Waveforms (continued) 0 OR 3V DI A DE GENERATOR (NOTE 5) 3V S1 A, B D B DE RL = 500 CL = 50pF (NOTE 6) 1.5V 1.5V tPDZH tPDHS 0V tPDHZ 50 A, B VOM = 0.25V VOM VOH + VOL 1.5V 2 VOH 0V Figure 5. Driver Enable and Disable Times VCC 0 OR 3V A DI GENERATOR (NOTE 5) RL = 500 S1 tPDLS B CL = 50pF (NOTE 6) 1.5V 1.5V tPDZL DE A, B D DE 3V 0V tPDLZ VCC A, B 50 VOM 0.25V VOL Figure 6. Driver Enable and Disable Times A GENERATOR (NOTE 5) VID 50W R B 2.0V RO (A-B) CL = 20pF (NOTE 6) 1.0V 1.0V 0V tRPLH tRPHL VCC 1.0V 0V RO VOM VOM 0V Figure 7. Receiver Propagation Delay www.maximintegrated.com Maxim Integrated 9 MAX13442E/MAX13443E/ MAX13444E S3 +1.5V 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers S1 A VID -1.5V R RO VCC 1k S2 B GENERATOR (NOTE 5) CL = 20pF (NOTE 6) 50 3V RE 1.5V 0V tRPZH tRPSH tRPWAKE RO S1 OPEN S2 CLOSED VS3 = 1.5V 3V RE 1.5V VOH VCC RO 1.5V 1.5V 0V 3V RE 1.5V 0V VOL S1 OPEN S2 CLOSED VS3 = 1.5V 3V RE 1.5V 0V tRPHZ RO 0.5V tRPLZ VOH RO 0V 0V tRPZL tRPSL S1 CLOSED S2 OPEN VS3 = -1.5V S1 CLOSED S2 OPEN VS3 = -1.5V VCC 0.5V VOL Figure 8. Receiver Enable and Disable Times Note 5: The input pulse is supplied by a generator with the following characteristics: f = 5MHz, 50% duty cycle; tr 6ns; Z0 = 50. Note 6: CL includes probe and stray capacitance. www.maximintegrated.com Maxim Integrated 10 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Pin Description PIN NAME FUNCTION 1 RO Receiver Output. If the receiver is enabled and (VA- VB) -50mV, RO = high; if (VA - VB) -200mV, RO = low. 2 2 RE Receiver Output Enable. Pull RE low to enable RO. 3 -- DE Driver Output Enable. Force DE high to enable driver. Pull DE low to three-state the driver output. Drive RE high and pull DE low to enter low-power shutdown mode. 4 -- DI Driver Input. A logic-low on DI forces the noninverting output low and the inverting output high. A logic-high on DI forces the noninverting output high and the inverting output low. 5 5 GND 6 6 A Noninverting Receiver Input/Driver Output 7 7 B Inverting Receiver Input/Driver Output 8 8 VCC Positive Supply, VCC = +4.75V to +5.25V. For normal operation, bypass VCC to GND with a 0.1F ceramic capacitor. For full ESD protection, bypass VCC to GND with 1F ceramic capacitor. -- 3 DE Driver Output Enable. Pull DE low to enable the outputs. Force DE high to three-state the outputs. Drive RE and DE high to enter lowpower shutdown mode. -- 4 TXD J1708 Input. A logic-low on TXD forces outputs A and B to the dominant state. A logic-high on TXD forces outputs A and B to the recessive state. MAX13442E MAX13443E MAX13444E 1 www.maximintegrated.com Ground Maxim Integrated 11 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Function Tables Table 1. MAX13442E/MAX13443E (RS-485/RS-422) Table 3. MAX13442E/MAX13443E (RS-485/RS-422) TRANSMITTING RECEIVING INPUTS RE OUTPUTS DE DI A B RE 0 0 X High-Z High-Z 0 1 0 0 0 1 1 1 1 0 X 1 1 1 1 INPUTS OUTPUTS DE (VA - VB) RO 0 X -0.05V 1 1 0 X -0.2V 0 0 0 X Open/shorted 1 Shutdown Shutdown 1 1 X High-Z 0 0 1 1 0 X Shutdown 1 1 0 X = Don't care. X = Don't care. Table 2. MAX13444E (J1708) Application Table 4. MAX13444E (RS-485/RS-422) TRANSMITTING INPUTS OUTPUTS RECEIVING CONDITIONS INPUTS OUTPUTS TXD DE A B -- RE DE (VA - VB) RO 0 1 High-Z High-Z -- 0 X -0.05V 1 1 1 High-Z High-Z -- 0 X -0.2V 0 0 0 0 1 Dominant state 0 X Open/shorted 1 1 0 High-Z High-Z Recessive state 1 0 X High-Z 1 1 X Shutdown X = Don't care. www.maximintegrated.com Maxim Integrated 12 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Detailed Description The MAX13442E/MAX13443E/MAX13444E fault-protected transceivers for RS-485/RS-422 and J1708 communication contain one driver and one receiver. These devices feature fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted, or when they are connected to a terminated transmission line with all drivers disabled (see the True Fail-Safe section). All devices have a hot-swap input structure that prevents disturbances on the differential signal lines when a circuit board is plugged into a hot backplane (see the Hot-Swap Capability section). The MAX13442E/MAX13444E feature a reduced slew-rate driver that minimizes EMI and reduces reflections caused by improperly terminated cables, allowing error-free data transmission up to 250kbps (see the Reduced EMI and Reflections section). The MAX13443E driver is not slewrate limited, allowing transmit speeds up to 10Mbps. Driver The driver accepts a single-ended, logic-level input (DI) and transfers it to a differential, RS-485/RS-422 level output (A and B). Deasserting the driver enable places the driver outputs (A and B) into a high-impedance state. Receiver The receiver accepts a differential, RS-485/RS-422 level input (A and B), and transfers it to a single-ended logiclevel output (RO). Deasserting the receiver enable places the receiver inputs (A and B) into a high-impedance state (see Table 1-Table 4). Low-Power Shutdown The MAX13442E/MAX13443E/MAX13444E offer a lowpower shutdown mode. Force DE low and RE high to shut down the MAX13442E/MAX13443E. Force DE and RE high to shut down the MAX13444E. A time delay of 50ns prevents the device from accidentally entering shutdown due to logic skews when switching between transmit and receive modes. Holding DE low and RE high for at least 800ns guarantees that the MAX13442E/MAX13443E enter shutdown. In shutdown, the devices consume a maximum 20A supply current. 80V Fault Protection The driver outputs/receiver inputs of RS-485 devices in industrial network applications often experience voltage faults resulting from shorts to the power grid that exceed the -7V to +12V range specified in the EIA/TIA-485 standard. In these applications, ordinary RS-485 devices (typical absolute maximum -8V to +12.5V) require costly external protection devices. To reduce system complexity and eliminate this need for external protection, the driver www.maximintegrated.com outputs/receiver inputs of the MAX13442E/MAX13444E withstand voltage faults up to 80V (60V for the MAX13443E) with respect to ground without damage. Protection is guaranteed regardless whether the device is active, shut down, or without power. True Fail-Safe The MAX13442E/MAX13443E/MAX13444E use a -50mV to -200mV differential input threshold to ensure true fail-safe receiver inputs. This threshold guarantees the receiver outputs a logic-high for shorted, open, or idle data lines. The -50mV to -200mV threshold complies with the 200mV threshold EIA/TIA-485 standard. 15kV ESD Protection As with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against ESD encountered during handling and assembly. The MAX13442E/ MAX13443E/MAX13444E receiver inputs/driver outputs (A, B) have extra protection against static electricity found in normal operation. Maxim's engineers have developed state-of-the-art structures to protect these pins against 15kV ESD without damage. After an ESD event, the MAX13442E/MAX13443E/MAX13444E continue working without latchup. ESD protection can be tested in several ways. The receiver inputs are characterized for protection to 15kV using the Human Body Model. ESD Test Conditions ESD performance depends on a number of conditions. Contact Maxim for a reliability report that documents test setup, methodology, and results. Human Body Model Figure 9a shows the Human Body Model, and Figure 9b shows the current waveform it generates when discharged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the device through a 1.5k resistor. Driver Output Protection Two mechanisms prevent excessive output current and power dissipation caused by faults or bus contention. The first, a foldback current limit on the driver output stage, provides immediate protection against short circuits over the whole 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. Normal operation resumes when the die temperature cools to +140C, resulting in a pulsed output during continuous short-circuit conditions. Maxim Integrated 13 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Hot-Swap Capability Hot-Swap Input Circuitry Hot-Swap Inputs Inserting circuit boards into a hot, or powered, backplane may cause voltage transients on DE, RE, and receiver inputs A and B that can lead to data errors. For example, upon initial circuit board insertion, the processor undergoes a power-up sequence. During this period, the highimpedance state of the output drivers makes them unable to drive the MAX13442E/MAX13443E/MAX13444E enable inputs to a defined logic level. Meanwhile, leakage currents of up to 10A from the high-impedance output, or capacitively coupled noise from VCC or GND, could cause an input to drift to an incorrect logic state. To prevent such a condition from occurring, the MAX13442E/MAX13443E/ MAX13444E feature hot-swap input circuitry on DE, and RE to guard against unwanted driver activation during hot-swap situations. The MAX13444E has hot-swap input circuitry only on RE. When VCC rises, an internal pulldown (or pullup for RE) circuit holds DE low for at least 10s, and until the current into DE exceeds 200A. After the initial power-up sequence, the pulldown circuit becomes transparent, resetting the hot-swap tolerable input. RC 1M CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF At the driver-enable input (DE), there are two NMOS devices, M1 and M2 (Figure 10). When VCC ramps from zero, an internal 15s timer turns on M2 and sets the SR latch, which also turns on M1. Transistors M2, a 2mA current sink, and M1, a 100A current sink, pull DE to GND through a 5.6k resistor. M2 pulls DE to the disabled state against an external parasitic capacitance up to 100pF that may drive DE high. After 15s, the timer deactivates M2 while M1 remains on, holding DE low against three-state leakage currents that may drive DE high. M1 remains on until an external current source overcomes the required input current. At this time, the SR latch resets M1 and turns off. When M1 turns off, DE reverts to a standard, high-impedance CMOS input. Whenever VCC drops below 1V, the input is reset. A complementary circuit for RE uses two PMOS devices to pull RE to VCC. RD 1.5k DISCHARGE RESISTANCE VCC DEVICE UNDER TEST STORAGE CAPACITOR 15s TIMER TIMER Figure 9a. Human Body ESD Test Model IP 100% 90% Ir PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) DE (HOT SWAP) 5.6k AMPERES 100A 36.8% 10% 0 M1 0 tRL M2 TIME tDL CURRENT WAVEFORM Figure 9b. Human Body Model Current Waveform www.maximintegrated.com 2mA Figure 10. Simplified Structure of the Driver Enable Pin (DE) Maxim Integrated 14 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Applications Information 128 Transceivers on the Bus The MAX13442E/MAX13443E/MAX13444E transceivers 1/4-unit-load receiver input impedance (48k) 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. Reduced EMI and Reflections The MAX13442E/MAX13444E are slew-rate limited, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 11 shows the driver output waveform and its Fourier analysis of a 125kHz signal transmitted by a MAX13443E. High-frequency harmonic components with large amplitudes are evident. Figure 12 shows the same signal displayed for the MAX13442E transmitting under the same conditions. Figure 12's high-frequency harmonic components are much lower in amplitude, compared with Figure 11's, and the potential for EMI is significantly reduced. 0 500kHz/div length = tRISE/(10 x 1.5ns/ft) where tRISE is the transmitter's rise time. For example, the MAX13442E's rise time is typically 800ns, which results in excellent waveforms with a stub length up to 53ft. A system can work well with longer unterminated stubs, even with severe reflections, if the waveform settles out before the UART samples them. RS-485 Applications The MAX13442E/MAX13443E/MAX13444E transceivers provide bidirectional data communications on multipoint bus transmission lines. Figure 13 shows a typical network application circuit. The RS-485 standard covers line lengths up to 4000ft. To minimize reflections and reduce data errors, terminate the signal line at both ends in its characteristic impedance, and keep stub lengths off the main line as short as possible. 20dB/div 20dB/div 2V/div 2V/div 5.00MHz Figure 11. Driver Output Waveform and FFT Plot of the MAX13443E Transmitting a 125kHz Signal www.maximintegrated.com In general, a transmitter's rise time relates directly to the length of an unterminated stub that can be driven with only minor waveform reflections. The following equation expresses this relationship conservatively: 0 500kHz/div 5.00MHz Figure 12. Driver Output Waveform and FFT Plot of the MAX13442E Transmitting a 125kHz Signal Maxim Integrated 15 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers J1708 Applications The MAX13444E is designed for J1708 applications. To configure the MAX13444E, connect DE and RE to GND. Connect the signal to be transmitted to TXD. Terminate the bus with the load circuit as shown in Figure 14. The drivers used by SAE J1708 are used in a dominant-mode application. DE is active low; a high input on DE places the outputs in high impedance. When the driver is disabled (TXD high or DE high), the bus is pulled high by external bias resistors R1 and R2. Therefore, a logic-level high is encoded as recessive. When all transceivers are idle in this configuration, all receivers output logic-high because of the pullup resistor on A and pulldown resistor on B. R1 and R2 provide the bias for the recessive state. C1 and C2 combine to form a lowpass filter, effective for reducing FM interference. R2, C1, R4, and C2 combine to form a 1.6MHz lowpass filter, effective for reducing AM interference. Because the bus is unterminated, at high frequencies, R3 and R4 perform a pseudotermination. This makes the implementation more flexible, as no specific termination nodes are required at the ends of the bus. 120 120 DE B B DI D D DI DE RO A B A B A A R R RO RE RE R R D D MAX13442E MAX13443E DI DE RO RE DI DE RO RE Figure 13. MAX13442E/MAX13443E Typical RS-485 Network www.maximintegrated.com Maxim Integrated 16 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Chip Information PROCESS: BiCMOS DE TX D TXD B R1 4.7k R3 47 C1 2.2nF A J1708 BUS R4 47 PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 8 SO S8+4 21-0041 90-0096 R2 4.7k R RO 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. C2 2.2nF MAX13444E RX Package Information VCC RE Figure 14. J1708 Application Circuit (See Tables 2 and 4) Pin Configurations and Typical Operating Circuits (continued) DE + + VCC RO 1 RE 2 7 B RE 2 7 B DE 3 6 A DE 3 6 5 GND TXD 4 R D SO www.maximintegrated.com TXD 4 MAX13444E 8 VCC 8 RO 1 R A 5 GND D SO RT D RT TXD B A RO R RE Maxim Integrated 17 MAX13442E/MAX13443E/ MAX13444E 15kV ESD-Protected, 80V Fault-Protected, Fail-Safe RS-485/J1708 Transceivers Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 10/05 Initial release 1 3/06 Corrected the part numbers in the conditions for VOC in the DC Electrical Characteristics table; corrected the A, B current units from mA to FA for the A, B Current vs. A, B Voltage (to Ground) graphs in the Typical Operating Characteristics section 2 11/10 Added lead(Pb)-free parts to the Ordering Information table; added the soldering temperature to the Absolute Maximum Ratings section; updated Table 2 outputs 3 3/11 Added an automotive qualified part to the Ordering Information; added the Package Thermal Characteristics section DESCRIPTION -- 2, 7 1, 2, 12 1, 2 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) 2011 Maxim Integrated Products, Inc. 18 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Maxim Integrated: MAX13442EASA+ MAX13443EASA+ MAX13442EASA+T MAX13443EASA+T MAX13444EASA+ MAX13444EASA+T