19-5254; Rev 0; 4/10 RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors The MAX13450E/MAX13451E are half-duplex and fullduplex RS-485/RS-422 transceivers. These devices feature internal 100I and 120I termination resistors. The resistor values are pin selectable. A logic supply input allows interfacing to logic levels down to +1.8V. The MAX13450E/MAX13451E feature strong drivers specified to drive low-impedance lines found when a fully loaded bus, based on today’s 100I characteristic impedance cable, is doubly terminated. Both devices allow slew-rate limiting of the driver output to reduce EMI and reflections for data rates up to 500kbps. The MAX13451E has a FAULT alarm indication output to signal to the system that an error condition exists in the driver. The MAX13451E also features a logic inversion function. The logic inversion allows phase reversal of the A-B signals in case these are inadvertently connected wrongly. The MAX13450E/MAX13451E have 1/8-unit load receiver input impedance, allowing up to 256 transceivers on the bus. All driver outputs are protected to Q30kV ESD using the Human Body Model (HBM). The MAX13450E/MAX13451E are available in a 14-pin TSSOP package and operate over the automotive -40NC to +125NC temperature range. Applications Features S 100I/120I Pin-Selectable Internal Termination Resistors S Driver Drives 100I Double Termination S 20Mbps (max) Data Rate S Pin-Selectable Slew-Rate Limiting S Logic Supply Input Allows Interfacing Down to 1.8V S Driver Fault-Indication Output (MAX13451E) S Inverting of A, B Line Polarity (MAX13451E) S High-Impedance Driver Output/Receiver Input When VCC Supply is Removed S Hot-Swap Input Structure on DE, RE, and TERM S Extended ESD Protection ±30kV Human Body Model ±15kV Air Gap Discharge per IEC 61000-4-2 ±7kV Contact Discharge per IEC 61000-4-2 S 1/8-Unit Load Allows Up to 256 Transceivers on the Bus S Thermal and Overcurrent Protected S Fail-Safe Receivers S +4.5V to +5.5V Supply Voltage Range Functional Diagram (MAX13451E) VL Industrial Control Systems Portable Industrial Equipment SRL Motor Control MAX13451E INV Security Networks D DI Medical Networks Ordering Information/ Selector Guide FAULT DE B TERM HALF/FULL DUPLEX PIN-PACKAGE MAX13450EAUD+ Full 14 TSSOP-EP* MAX13451EAUD+ Half 14 TSSOP-EP* PART VCC Note: All devices are specified over the -40°C to +125°C operating temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. LOGIC LOGIC-LEVEL TRANSLATION RE A RO TERM100 GND ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX13450E/MAX13451E General Description MAX13450E/MAX13451E RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND.) VCC, VL . ..................................................................-0.3V to +6V DE, RE, DI, RO, TERM, TERM100, SRL . .... -0.3V to (VL + 0.3V) INV, FAULT ................................................. -0.3V to (VL + 0.3V) A, B, Z, Y...................................................................-8V to +13V A to B (High-Z State) . ........................................................ +14V B to A (High-Z State) . ........................................................ +14V Short-Circuit Duration (RO, Y, Z) to GND................. Continuous Continuous Power Dissipation (TA = +70NC) 14-Pin TSSOP (derate 25.6mW/NC above +70NC)......2051mW Package Junction-to-Ambient Thermal Resistance (BJA) (Note 1) ............................................39NC/W Package Junction-to-Case Thermal Resistance (BJC) (Note 1)...............................................3NC/W Operating Temperature Range . ...................... -40NC to +125NC Storage Temperature Range ........................... -65NC to +150NC Junction Temperature .....................................................+150NC Lead Temperature (soldering, 10s) ................................+300NC Soldering Temperature (reflow).......................................+260NC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. 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. ELECTRICAL CHARACTERISTICS (VCC = +4.5V to +5.5V, VL = +1.62V to 4.2V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, VL = +1.8V, and TA = +25NC.) (Note 2) PARAMETER Supply Voltage Logic Supply Voltage Supply Current Logic Supply Current Shutdown Current SYMBOL CONDITIONS MIN VCC 4.5 VL 1.62 ICC IL ISHDN TYP 1.8 MAX UNITS 5.5 V 4.2 V DE = RE = high, TERM = high, no load 6 DE = RE = low, TERM = low, no load 12 Current into VL, no load on RO, device not switching, DE = RE = high 2 FA Current into VCC, DE = low, RE = TERM = high 30 FA Current into VCC, DE = low, RE = high, TERM = low 8 mA mA DRIVER Differential Driver Output Change in Magnitude of Differential Output Voltage VOD RDIFF = 100I, Figure 1 (Note 3) 2.0 VCC RDIFF = 46I, Figure 1 (Note 3) 1.5 VCC DVOD RDIFF = 100I or 46I, Figure 1 (Note 3) VOC RDIFF = 100I or 46I, Figure 1 (Note 3) Change In Magnitude of Common-Mode Voltage DVOC RDIFF = 100I or 46I, Figure 1 (Note 3) Driver Short-Circuit Output Current IOSD 0V P VOUT P +12V -7V P VOUT P 0V -250 Driver Short-Circuit Foldback Output Current IOSDF (VCC - 1V) P VOUT P +12V +15 Driver Common-Mode Output Voltage VCC/2 0.2 V 3 V 0.2 V +280 -7V P VOUT P 0V 2 _______________________________________________________________________________________ V -15 mA mA RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors (VCC = +4.5V to +5.5V, VL = +1.62V to 4.2V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, VL = +1.8V, and TA = +25NC.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS RECEIVER Input Current (A and B) IA, B DE = RE = GND; TERM = VL; VCC = GND or 5.5V Receiver Differential Threshold Voltage VTH -7V P VCM P +12V, DE = RE = GND; TERM = VL; VCC = GND Receiver Input Hysteresis DVTH VA or VB = +12V 125 VA or VB = -7V -100 VA or VB = +12V -200 VA + VB = 0V FA -50 15 mV mV LOGIC INTERFACE Input High Voltage VIH DI, DE, RE, TERM, SRL, TERM100, INV Input Low Voltage VIL DI, DE, RE, TERM, SRL, TERM100, INV Input Current IIN 2/3 x VL -1 Receiver Output High Voltage VROH DI, DE, RE, TERM, TERM100, SRL, INV IOUT = -1mA Receiver Output Low Voltage VROL IOUT = +1mA Three-State Output Current at Receiver IOZR 0V P VRO P VL -1 Receiver Output Short-Circuit Current IOSR 0V P VRO P VL Q1 Fault Output High Voltage (MAX13451E) VFAULTH Fault condition, IOUT = -1mA Fault Output Low Voltage (MAX13451E) VFAULTL Nonfault condition; IOUT = +1mA V 1/3 x VL V +1 FA VL - 0.6 V +0.01 0.4 V +1 FA Q80 mA VL - 0.6 V 0.4 V TERMINATION RESISTOR 100I Termination Resistor R100 TERM = low, TERM100 = high 85 100 115 I 120I Termination Resistor R120 TERM = low, TERM100 = low 101 120 139 I Single-Ended Input Capacitance vs. GND CIN f = 1MHz (MAX13451E only) 40 pF ESD PROTECTION ESD Protection (A, B, Y, Z) ESD Protection (All Other Pins) Human Body Model Q30 IEC 61000-4-2 Air Gap Discharge Q15 IEC 61000-4-2 Contact Discharge Q7 Human Body Model Q2 kV _______________________________________________________________________________________ 3 MAX13450E/MAX13451E ELECTRICAL CHARACTERISTICS (continued) MAX13450E/MAX13451E RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors SWITCHING CHARACTERISTICS—SRL = HIGH (VCC = +4.5V to +5.5V, VL = +1.62V to 4.2V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, VL = +1.8V and TA = +25NC.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DRIVER Driver Propagation Delay Differential Driver Output Skew |tDPLH - tDPHL| Driver Differential Output Rise or Fall Time Maximum Data Rate tDPLH tDPHL tDSKEW tHL tLH 800 RDIFF = 54I, CL = 50pF, Figures 2 and 3 800 100 RDIFF = 54I, CL = 50pF, Figure 3 RDIFF = 54I, CL = 50pF, Figures 2 and 3 DRMAX 100 600 100 600 500 ns ns ns kbps Driver Enable from Shutdown to Output High S2 closed, RL = 500I, CL = 100pF, tDZH(SHDN) Figures 4 and 5 4500 ns Driver Enable from Shutdown to Output Low tDZL(SHDN) S1 closed, RL = 500I, CL = 100pF, Figures 4 and 5 5200 ns Driver Disable Delay tDLZ, tDHZ Figures 4 and 5 100 ns Driver Enable Delay tDZL, tDZH Figures 4 and 5 2500 ns CL = 15pF, |VID| R 2.0V; tLH, tHL P 15ns, Figures 6 and 7 200 RECEIVER Receiver Propagation Delay tRPLH tRPHL Receiver Output Skew tRSKEW Maximum Data Rate DRMAX 200 CL = 15pF, Figures 6 and 7 30 500 ns ns kbps Receiver Enable to Output High tRZH S2 closed, CL = 100pF, RL = 500I, Figures 8 and 9 50 ns Receiver Enable to Output Low tRZL S1 closed, CL = 100pF, RL = 500I, Figures 8 and 9 50 ns Receiver Disable from High tRHZ Figures 8 and 9 50 ns Receiver Disable from Low tRLZ Figures 8 and 9 50 ns Receiver Enable from Shutdown to Output High tRZH(SHDN) Figures 8 and 9 5000 ns Receiver Enable from Shutdown to Output Low tRZL(SHDN) Figures 8 and 9 5000 ns TERMINATION RESISTOR Turn-Off Time tRTZ Figure 10 120 Fs Turn-On Time tRTEN Figure 10 1 Fs 4 _______________________________________________________________________________________ RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors (VCC = +4.5V to +5.5V, VL = +1.62V to 4.2V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, VL = +1.8V, and TA = +25NC.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DRIVER Driver Propagation Delay tDPLH tDPHL 50 RDIFF = 54I, CL = 50pF, Figures 2 and 3 50 ns Differential Driver Output Skew |tDPLH - tDPHL| tDSKEW RDIFF = 54I, CL = 50pF, Figure 3 6 ns Driver Differential Output Rise or Fall Time tHL, tLH RDIFF = 54I, CL = 50pF, Figures 2 and 3 15 ns Maximum Data Rate DRMAX 20 Mbps Driver Enable from Shutdown to Output High S2 closed, RL = 500I, CL = 100pF, tDZH(SHDN) Figures 4 and 5 2000 ns Driver Enable from Shutdown to Output Low tDZL(SHDN) S1 closed, RL = 500I, CL = 100pF, Figures 4 and 5 2000 ns Driver Disable Delay tDLZ, tDHZ Figures 4 and 5 100 ns Driver Enable Delay tDZL, tDZH Figures 4 and 5 100 ns CL = 15pF, |VID| R 2.0V; tLH, tHL P 15ns, Figures 6 and 7 50 RECEIVER Receiver Propagation Delay tRPLH tRPHL Receiver Output Skew tRSKEW Maximum Data Rate DRMAX 50 CL = 15pF, Figures 6 and 7 6 20 ns ns Mbps Receiver Enable to Output High tRZH S2 closed, CL = 100pF, RL = 500I, Figures 8 and 9 50 ns Receiver Enable to Output Low tRZL S1 closed, CL = 100pF, RL = 500I, Figures 8 and 9 50 ns Receiver Disable Time from High tRHZ Figures 8 and 9 50 ns Receiver Disable Time from Low tRLZ Figures 8 and 9 50 ns Receiver Enable from Shutdown to Output High tRZH(SHDN) Figures 8 and 9 2000 ns Receiver Enable from Shutdown to Output Low tRZL(SHDN) Figures 8 and 9 2000 ns TERMINATION RESISTOR Turn-Off Time tRTZ Figure 10 120 Fs Turn-On Time tRTEN Figure 10 1 Fs Note 2: All devices are 100% production tested at TA = +25°C. Limits over temperature are guaranteed by design. Note 3: Termination resistance is disabled (TERM = high). _______________________________________________________________________________________ 5 MAX13450E/MAX13451E SWITCHING CHARACTERISTICS—SRL = LOW Typical Operating Characteristics (VCC = +5V, VL = +1.8V, TA = +25NC, unless otherwise noted.) SHUTDOWN CURRENT vs. TEMPERATURE RL = 100Ω 30 20 6 5 4 3 1 10 2 1 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 100 0 10 20 30 40 50 60 TEMPERATURE (°C) OUTPUT CURRENT (mA) RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE RECEIVER PROPAGATION DELAY vs. TEMPERATURE 1.6 1.4 1.2 IOUT = 1mA 0.4 0.3 0.2 0.1 100 RECEIVER PROPAGATION DELAY (ns) 1.8 0.5 RECEIVER OUTPUT LOW VOLTAGE (V) IOUT = 1mA MAX13450E/51E toc05 DATA RATE (Mbps) MAX13450E/51E toc04 2.0 3 SINK 0 0 0.1 SOURCE 4 1 NO LOAD MAX13450E/51E toc03 7 2 10 0 1.0 INV = HIGH 80 60 70 INV = LOW 40 20 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) DRIVER DIFFERENTIAL OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE TRANSMITTER OUTPUT CURRENT vs. TRANSMITTER OUTPUT HIGH VOLTAGE TRANSMITTER OUTPUT CURRENT vs. TRANSMITTER OUTPUT LOW VOLTAGE 60 40 20 100 80 60 40 20 0 0 0 1 2 3 4 DRIVER DIFFERENTIAL OUTPUT VOLTAGE (V) 5 200 MAX13450E/51E toc09 80 120 TRANSMITTER OUTPUT CURRENT (mA) MAX13450E/51E toc07 100 TRANSMITTER OUTPUT CURRENT (mA) RECEIVER OUTPUT HIGH VOLTAGE (V) 8 5 MAX13450E/51E toc06 40 MAX13450E/51E toc02 RL = 54Ω 50 9 MAX13450E/51E toc08 SUPPLY CURRENT (mA) 60 10 SHUTDOWN CURRENT (µA) MAX13450E/51E toc01 70 RECEIVER OUTPUT VOLTAGE vs. OUTPUT CURRENT RECEIVER OUTPUT VOLTAGE (V) SUPPLY CURRENT vs. DATA RATE DRIVER DIFFERENTIAL OUTPUT CURRENT (mA) MAX13450E/MAX13451E RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors 180 160 140 120 100 80 60 40 20 0 -7 -2 3 TRANSMITTER OUTPUT HIGH VOLTAGE (V) -3 2 7 TRANSMITTER OUTPUT LOW VOLTAGE (V) 6 _______________________________________________________________________________________ 12 RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors RDIFF = 54Ω 3 2 100 80 -10 R100 MAGNITUDE 60 R100 PHASE -20 40 1 20 0 -30 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 0.1 10 100 FREQUENCY (MHz) 120Ω TERMINATION RESISTOR vs. FREQUENCY TERMINATION RESISTANCE vs. TEMPERATURE 0 120 80 60 R120 PHASE -20 40 20 -30 0 0.1 1 10 100 120 120Ω RESISTOR 110 100 100Ω RESISTOR 90 80 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) FREQUENCY (MHz) DRIVER PROPAGATION DELAY (250kbps) (MAX13451E) DRIVER ENABLE TIME FROM SHUTDOWN (MAX13451E) MAX13450E/51E toc14 SRL = HIGH DE = HIGH RE = HIGH PHASE (DEGREE) -10 R120 MAGNITUDE TERMINATION RESISTANCE (Ω) 130 MAX13450E/51E toc13 MAX13450E/51E toc12 100 1 TEMPERATURE (°C) 140 MAGNITUDE (Ω) 0 120 MAGNITUDE (Ω) 4 MAX13450E/51E toc11 140 MAX13450E/51E toc10 5 100Ω TERMINATION RESISTOR vs. FREQUENCY PHASE (DEGREE) DRIVER DIFFERENTIAL OUTPUT VOLTAGE (V) DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE MAX13450E/51E toc15 DE 2V/div DI 1V/div A 2V/div A 1V/div B 1V/div 1µs/div SRL = LOW RE = HIGH B 2V/div 200ns/div _______________________________________________________________________________________ 7 MAX13450E/MAX13451E Typical Operating Characteristics (continued) (VCC = +5V, VL = +1.8V, TA = +25NC, unless otherwise noted.) MAX13450E/MAX13451E RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors Test Circuits and Waveforms A/Y VL RDIFF DE 2 A DI VOD VID CL RDIFF B RDIFF VOC 2 B/Z Figure 1. Driver DC Test Load Figure 2. Driver Timing Test Circuit f = 1MHz, tLH ≤ 3ns, tHL ≤ 3ns VL DI VL/2 VL/2 0V 1/2 VO tDPHL tDPLH B A 1/2 VO VO VO VDD 90% 90% 0V 10% 10% -VO tHL tLH tDSKEW = |tDPLH - tDPHL| Figure 3. Driver Propagation Delays 8 _______________________________________________________________________________________ CL RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors VL DE VL/2 VL/2 0V tDLZ tDZL(SHDN),tDZL VCC (VCC + VOL)/2 A/Y, B/Z VOL VOL + 0.25V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH VOH VOH/2 A/Y, B/Z VOH - 0.25V 0V tDZH(SHDN),tDZH tDHZ Figure 4. Driver Enable and Disable Times 500Ω OUTPUT UNDER TEST S1 VCC B CL RECEIVER OUTPUT R VID ATE A S2 Figure 5. Driver-Enable and Disable-Timing Test Load Figure 6. Receiver Propagation Delay Test Circuit f = 1MHz, tLH ≤ 3ns, tHL ≤ 3ns A 1V B -1V tRPHL tRPLH VROH RO VL/2 VROL VL/2 tRSKEW = |tRPHL - tRPLH| Figure 7. Receiver Propagation Delays _______________________________________________________________________________________ 9 MAX13450E/MAX13451E Test Circuits and Waveforms (continued) MAX13450E/MAX13451E RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors Test Circuits and Waveforms (continued) VL RE VL/2 VL/2 0V tRZL(SHDN), tRZL tRHZ VL RO (VL + VROL)/2 VROL ROH + 0.25V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH VROH VROH/2 RO ROH - 0.25V 0V tRZH(SHDN), tRZH DI = 0V tRHZ Figure 8. Receiver Enable and Disable Times VCC S1 500Ω RO CL S2 Figure 9. Receiver Enable and Disable Times IA = VAB/RD VAB = VA - VB RD = R100 OR R200 A RO RECEIVER TERM VL VL/2 TERM 0V B tREN IA tREN 90% 10% Figure 10. Termination Resistor Turn-On/-Off Times 10 ������������������������������������������������������������������������������������� RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors TOP VIEW TOP VIEW + + DE 1 14 SRL DE 1 14 SRL RE 2 13 TERM100 RE 2 13 TERM100 DI 3 12 Z DI 3 12 B VCC 4 11 GND VCC 4 11 GND TERM 5 10 Y TERM 5 10 A VL 6 9 B VL 6 9 FAULT RO 7 8 A RO 7 8 INV MAX13450E EP TSSOP MAX13451E EP TSSOP Pin Description PIN NAME FUNCTION 1 DE Driver-Output Enable. Drive DE low to put the driver output in three-state. Drive DE high to enable the driver. DE is referenced to VL. 2 2 RE Receiver-Output Enable. Drive RE low to enable the RO. Drive RE high to disable the RO output and put the RO output in a high-impedance state. RE is referenced to VL. 3 3 DI Driver Input. Drive DI low to force the noninverting output low and the inverting output high. Drive DI high to force the noninverting output high and inverting output low. DI is referenced to VL. 4 4 VCC 5 5 TERM 6 6 VL Logic Supply Voltage. Bypass VL to GND with a 0.1FF ceramic capacitor placed as close as possible to the device. 7 — RO Receiver Output. When receiver is enabled and VA - VB R -50mV, RO is high. If VA - VB P -200mV, RO is low. RO is referenced to VL. — 7 RO Receiver Output. When INV is low, receiver is enabled and VA - VB R -50mV, RO is high. If VA - VB P -200mV, RO is low. When INV is high, receiver is enabled and VA - VB R -50mV, RO is low. If VA - VB P -200mV, RO is high. RO is referenced to VL. 8 — A Noninverting Receiver Input — 10 A If INV is low, A is a noninverting receiver input and a noninverting driver output. If INV is high, A is an inverting receiver input and an inverting driver output. 9 — B Inverting Receiver Input — 12 B If INV is low, B is an inverting receiver input and an inverting driver output. If INV is high, B is a noninverting receiver input and a noninverting driver output. MAX13450E MAX13451E 1 Power-Supply Voltage. Bypass VCC to GND with a 0.1FF ceramic capacitor placed as close as possible to the device. Active-Low Termination Resistor Enable. Drive TERM low to enable the internal termination resistor. TERM is referenced to VL. ______________________________________________________________________________________ 11 MAX13450E/MAX13451E Pin Configurations MAX13450E/MAX13451E RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors Pin Description (continued) PIN MAX13450E MAX13451E NAME FUNCTION 10 — Y 11 11 GND Noninverting Driver Output 12 — Z 13 13 TERM100 Termination Resistor Value Selection Input. Drive TERM100 low to select a 120I termination and high to select a 100I termination. The TERM100 input is referenced to VL. 14 14 SRL Slew-Rate Limiting-Enable Input. Drive SRL high to enable slew-rate limiting and low to disable slew-rate limiting. The SRL input is referenced to VL. — 8 INV Inversion Input. Drive INV high to internally swap RO logic level with respect to A and B signals. — 9 FAULT — — EP Ground Inverting Driver Output Fault Flag Output. FAULT asserts high in overcurrent conditions or if A/B are forced below GND or above VCC when the driver is enabled. FAULT is referenced to VL. Exposed Pad Function Tables Table 1. Termination Resistor Control (MAX13450E/MAX13451E) TERM Low DE RE X TERMINATION RESISTOR X High X X Not activated Activated RE High Low TERM High STATE Shutdown Table 3. Function Table for Transmitter (MAX13450E) INPUT Low DI Y Z Low X High-Z High-Z Low Low High High High Low OUTPUT A-B RO X High-Z R -50mV or Open High P -200mV Low Table 5. INV Input Function Table for Transmitter (MAX13451E) INPUT OUTPUT DE INV DI A B Low X X High-Z High-Z Low Low High High High Low Low High Low High Low High OUTPUT DE High INPUT RE High Table 2. Shutdown Control (MAX13450E/ MAX13451E) DE Table 4. Function Table for Receiver (MAX13450E) Low High High 12 ������������������������������������������������������������������������������������� RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors Table 6. INV Input Function Table for Receiver (MAX13451E) INPUT RE High A-B RO X X High-Z Low R -50mV or Short or Open High P -200mV Low R -50mV or Open Low P -200mV High High VL VCC SRL OUTPUT INV Low Functional Diagram (MAX13450E) Detailed Description The MAX13450E is a full-duplex, RS-485/RS-422compatible transceiver and the MAX13451E is a halfduplex, RS-485/RS-422-compatible transceiver. Both devices have an internal 100I/120I termination resistor. The MAX13450E/MAX13451E have a VL supply voltage input to support down to a +1.8V voltage logic interface. The MAX13450E/MAX13451E feature a 1/8-unit load receiver input impedance, allowing up to 256 transceivers on the bus. All line interface pins are protected to Q30kV ESD based on the HBM. These devices also include fail-safe circuitry, guaranteeing a defined logiclevel receiver output when the receiver inputs are open or shorted. The MAX13450E/MAX13451E allow slew-rate-limited driver outputs for lower data rates below 500kbps. The SRL reduces the slew rate, which reduces EMI emissions and reflections caused by improperly terminated cables. The MAX13451E has a FAULT output that indicates a fault condition on the driver. The MAX13451E also has an INV input that inverts the phase of A and B pins. Termination Resistor The MAX13450E/MAX13451E feature a selectable internal termination resistor. Drive the TERM input low to enable the internal termination resistor. Drive the TERM input high to disable the internal termination resistor. Z DI D Y DE MAX13450E TERM LOGIC-LEVEL TRANSLATION RE B RO A TERM100 GND Drive the TERM100 input high to select the 100I termination resistor. Drive TERM100 input low to select the 120I termination resistor. INV Input (MAX13451E) The INV input of the MAX13451E reverses the polarity of the RO receiver output (see Table 5 and 6). If the INV input is high then the RO output is low under fail-safe receiver conditions. This is the opposite polarity of normal fail-safe operations. Fault Condition (MAX13451E) The MAX13451E also has a FAULT output to indicate a fault condition. The FAULT output is active high when there is a short circuit at the driver’s output, an over/ undervoltage at the driver’s outputs, or the device’s temperature is higher than +150NC. ______________________________________________________________________________________ 13 MAX13450E/MAX13451E Function Tables (continued) MAX13450E/MAX13451E RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors Thermal Shutdown When the devices’ temperature goes over +150NC, the termination resistor turns off, and the transmitter shuts down while the receiver stays active. Fail Safe The MAX13450E guarantee a logic-high receiver output when the receiver inputs are shorted or open, or when they are connected to a terminated transmission line with all drivers disabled. This is done by setting the receiver input threshold between -50mV and -200mV. If the differential receiver input voltage (A - B) is greater than or equal to -50mV, RO is logic-high. If (A - B) is less than or equal to -200mV, RO is logic-low. In the case of a terminated bus with all transmitters disabled, the receiver’s differential input voltage is pulled to 0V by the termination resistor. With the receiver thresholds of the MAX13450E, this results in RO being logic-high. The MAX13451E has the same fail-safe receiver behavior as the MAX13450E when the INV input is low. When the INV input is high, RO is low under the fail-safe condition. ESD Protection As with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against electrostatic discharges encountered during handling and assembly. The driver outputs and receiver inputs of the MAX13450E/MAX13451E have extra protection against static electricity. The ESD structures withstand high ESD in all states: normal operation, shutdown, and powered down. After an ESD event, the MAX13450E/MAX13451E keep working without latchup or damage. ESD protection can be tested in various ways. The transmitter outputs and receiver inputs of the MAX13450E/ MAX13451E are characterized for protection to the following limits: • Q30kV using the Human Body Model • Q 15kV using the Air Gap Discharge Method specified in IEC 61000-4-2 • Q 7kV using the Contact Discharge Method specified in IEC 61000-4-2 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 Figure 11a shows the Human Body Model, and Figure 11b 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 test device through a 1.5kI 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 MAX13450E/ MAX13451E help equipment designs to meet IEC 610004-2, without the need for additional ESD-protection components. The major difference between tests done using the Human Body Model and IEC 61000-4-2 is higher peak current in IEC 61000-4-2 because series resistance is lower in the IEC 61000-4-2 model. Hence, the ESD withstand voltage measured to IEC 61000-4-2 is generally lower than that measured using the Human Body Model. Figure 11c shows the IEC 61000-4-2 model, and Figure 11d shows the current waveform for the IEC 61000-4-2 ESD Contact Discharge test. Applications Information Typical Applications The MAX13450E transceiver is designed for full-duplex, bidirectional data communications on point-to-point or multipoint bus transmission lines (Figure 12). The MAX13451E transceiver is designed for half-duplex, bidirectional data communications on point-to-point or multipoint bus transmission lines (Figure 13). 256 Transceivers on the Bus The standard RS-485 receiver input impedance is oneunit load, and the standard driver can drive up to 32-unit loads. The MAX13450E/MAX13451E have a 1/8-unit load receiver input impedance, allowing up to 256 transceivers to be connected in parallel on one communication line. Any combination of these devices, as well as other RS-485 transceivers with a total of 32-unit loads or fewer, can be connected to the line. Reduced EMI and Reflections The MAX13450E/MAX13451E feature reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission up to 500kbps. 14 ������������������������������������������������������������������������������������� RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors RD 1500Ω CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE CS 100pF RC 50MΩ TO 100MΩ DISCHARGE RESISTANCE CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE DEVICE UNDER TEST STORAGE CAPACITOR Figure 11a. Human Body ESD Test Model IP 100% 90% DISCHARGE RESISTANCE DEVICE UNDER TEST STORAGE CAPACITOR Figure 11c. IEC 61000-4-2 ESD Test Model I 100% 90% PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) IPEAK Ir CS 150pF RD 330Ω AMPS 36.8% 10% 0 10% 0 TIME tRL tr = 0.7ns TO 1ns tDL CURRENT WAVEFORM t 30ns 60ns Figure 11b. Human Body Current Waveform Figure 11d. IEC 61000-4-2 ESD Generator Current Waveform Typical Application Circuits Z B Y A B Z A Y D R R D MAX13450E MAX13450E MASTER END SLAVE R D R D SLAVE 1 R D SLAVE 2 SLAVE N Figure 12. Full-Duplex, Multidrop (MAX13450E) ______________________________________________________________________________________ 15 MAX13450E/MAX13451E RC 1MΩ MAX13450E/MAX13451E RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors Typical Application Circuits (continued) MAX13451E MAX13451E D D B B A A R R R D R R D SLAVE 1 D SLAVE 2 SLAVE N Figure 13. Half-Duplex, Multidrop, and Point-to-Point Systems (MAX13451E) Package Information Low-Power Shutdown Mode Drive RE high, DE low, and TERM high to enter lowpower shutdown mode (see Table 2). Chip Information PROCESS: BiCMOS For the latest package outline information and land patterns, go to www.maxim-ic.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 DOCUMENT NO. 14 TSSOP-EP U14E+3 21-0108 16 ������������������������������������������������������������������������������������� RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors REVISION NUMBER REVISION DATE 0 4/10 DESCRIPTION Initial release PAGES CHANGED — Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2010 Maxim Integrated Products 17 Maxim is a registered trademark of Maxim Integrated Products, Inc. MAX13450E/MAX13451E Revision History