19-1474; Rev 0; 4/99 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers Devices in the MAX3483E family (MAX3483E/MAX3485E/ MAX3486E/MAX3488E/MAX3490E/MAX3491E) are ±15kV ESD-protected, +3.3V, low-power transceivers for RS-485 and RS-422 communications. Each device contains one driver and one receiver. The MAX3483E and MAX3488E feature slew-rate-limited drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission at data rates up to 250kbps. The partially slew-rate-limited MAX3486E transmits up to 2.5Mbps. The MAX3485E, MAX3490E, and MAX3491E transmit at up to 12Mbps. All devices feature enhanced electrostatic discharge (ESD) protection. All transmitter outputs and receiver inputs are protected to ±15kV using IEC 1000-4-2 AirGap Discharge, ±8kV using IEC 1000-4-2 Contact Discharge, and ±15kV using the Human Body Model. Drivers are short-circuit current limited and are protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic-high output if both inputs are open circuit. The MAX3488E, MAX3490E, and MAX3491E feature full-duplex communication, while the MAX3483E, MAX3485E, and MAX3486E are designed for halfduplex communication. Features ♦ ESD Protection for RS-485 I/O Pins ±15kV—Human Body Model ±8kV—IEC 1000-4-2, Contact Discharge ±15kV—IEC 1000-4-2, Air-Gap Discharge ♦ Operate from a Single +3.3V Supply— No Charge Pump Required ♦ Interoperable with +5V Logic ♦ Guaranteed 12Mbps Data Rate (MAX3485E/MAX3490E/MAX3491E) ♦ Slew-Rate Limited for Errorless Data Transmission (MAX3483E/MAX3488E) ♦ 2nA Low-Current Shutdown Mode (MAX3483E/MAX3485E/MAX3486E/MAX3491E) ♦ -7V to +12V Common-Mode Input Voltage Range ♦ Full-Duplex and Half-Duplex Versions Available ♦ Industry-Standard 75176 Pinout (MAX3483E/MAX3485E/MAX3486E) ♦ Current-Limiting and Thermal Shutdown for Driver Overload Protection Ordering Information Applications PART TEMP. RANGE MAX3483ECSA 0°C to +70°C PIN-PACKAGE 8 SO MAX3483ECPA 0°C to +70°C 8 Plastic DIP Transceivers for EMI-Sensitive Applications MAX3483EESA MAX3483EEPA MAX3485ECSA -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO 8 Plastic DIP 8 SO Integrated Services Digital Networks MAX3485ECPA 0°C to +70°C 8 Plastic DIP Packet Switching MAX3485EESA MAX3485EEPA -40°C to +85°C -40°C to +85°C 8 SO 8 Plastic DIP Telecommunications Industrial-Control Local Area Networks Ordering Information continued at end of data sheet. Selector Guide PART NUMBER GUARANTEED SUPPLY DATA RATE VOLTAGE (Mbps) (V) DRIVER/ SHUTDOWN ±15kV HALF/FULL SLEW-RATE RECEIVER CURRENT ESD DUPLEX LIMITED ENABLE (nA) PROTECTION PIN COUNT MAX3483E 0.25 Half Yes Yes 2 Yes 8 MAX3485E 12 Half No Yes 2 Yes 8 Half Yes Yes 2 Yes 8 Full Yes No — Yes 8 MAX3486E 2.5 MAX3488E 0.25 MAX3490E 12 Full No No — Yes 8 MAX3491E 12 Full No Yes 2 Yes 14 3.0 to 3.6 ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E General Description MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC).............................................................+7V Control Input Voltage (RE, DE).................................-0.3V to +7V Driver Input Voltage (DI)...........................................-0.3V to +7V Driver Output Voltage (A, B, Y, Z) .......................-7.5V to +12.5V Receiver Input Voltage (A, B)..............................-7.5V to +12.5V Receiver Output Voltage (RO)....................-0.3V to (VCC + 0.3V) Continuous Power Dissipation (TA = +70°C) 8-Pin SO (derate 5.88mW/°C above +70°C)..................471mW 8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) .....727mW 14-Pin SO (derate 8.33mW/°C above +70°C)................667mW 14-Pin Plastic DIP (derate 10mW/°C above +70°C) ......800mW Operating Temperature Ranges MAX34_ _ EC_ _ ...................................................0°C to +70°C MAX34_ _ EE_ _.................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10sec) .............................+300°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. DC ELECTRICAL CHARACTERISTICS (VCC = +3.3V ±0.3V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Differential Driver Output SYMBOL VOD CONDITIONS RL = 100Ω (RS-422), Figure 4 RL = 54Ω (RS-485), Figure 4 RL = 60Ω (RS-485), VCC = 3.3V, Figure 5 MIN TYP MAX 2.0 1.5 1.5 UNITS V Change in Magnitude of Driver Differential Output Voltage for Complementary Output States (Note 1) ∆VOD RL = 54Ω or 100Ω, Figure 4 0.2 V Driver Common-Mode Output Voltage VOC RL = 54Ω or 100Ω, Figure 4 3 V ∆VOC RL = 54Ω or 100Ω, Figure 4 0.2 V Change in Magnitude of Common-Mode Output Voltage (Note 1) Input High Voltage VIH DE, DI, RE Input Low Voltage VIL DE, DI, RE Logic Input Current IIN1 IIN2 DE = 0, VCC = 0 or 3.6V Input Current (A, B) Output Leakage (Y, Z) IO Output Leakage (Y, Z) in Shutdown Mode IO Receiver Differential Threshold Voltage VTH 2.0 V 0.8 V DE, DI, RE ±2 µA VIN = 12V VIN = -7V VOUT = 12V DE = 0, RE = 0, VCC = 0 or 3.6V, MAX3491E VOUT = -7V VOUT = 12V DE = 0, RE = VCC, VCC = 0 or 3.6V, MAX3491E VOUT = -7V 1.0 -0.8 20 -20 1 -1 -7V ≤ VCM ≤ 12V -0.2 0.2 mA µA µA V Receiver Input Hysteresis ∆VTH VCM = 0 Receiver Output High Voltage VOH IOUT = -1.5mA, VID = 200mV, Figure 6 Receiver Output Low Voltage VOL IOUT = 2.5mA, VID = 200mV, Figure 6 0.4 V Three-State (High-Impedance) Output Current at Receiver IOZR VCC = 3.6V, 0 ≤ VOUT ≤ VCC ±1 µA Receiver Input Resistance RIN -7V ≤ VCM ≤ 12V Supply Voltage Range VCC Supply Current ICC Supply Current in Shutdown Mode 2 ISHDN 50 mV VCC - 0.4 V 12 kΩ 3.0 3.6 DE = VCC, RE = 0 or VCC 1.1 2.2 DE = 0, RE = 0 0.95 1.9 DE = 0, RE = VCC, DI = VCC or 0 0.002 1 No load, DI = 0 or VCC _______________________________________________________________________________________ V mA µA 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E DC ELECTRICAL CHARACTERISTICS (continued) (VCC = +3.3V ±0.3V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL Driver Short-Circuit Output Current IOSD Receiver Short-Circuit Output Current IOSR ESD Protection for Y, Z, A, B CONDITIONS VOUT = -7V VOUT = 12V 0 ≤ VRO ≤ VCC IEC 1000-4-2 Air Discharge MIN TYP ±8 MAX -250 250 ±60 UNITS mA mA ±15 IEC 1000-4-2 Contact Discharge (MAX3483E, MAX3485E, MAX3486E, MAX3491E) ±8 IEC 1000-4-2 Contact Discharge (MAX3490E, MAX3488E)* ±6 Human Body Model ±15 kV *MAX3488E and MAX3491E will be compliant to ±8kV per IEC 1000-4-2 Contact Discharge by September 1999. DRIVER SWITCHING CHARACTERISTICS—MAX3485E/MAX3490E/MAX3491E (VCC = +3.3V, TA = +25°C.) PARAMETER Maximum Data Rate Driver Differential Output Delay Driver Differential Output Transition Time Driver Propagation Delay, Low-to-High Level Driver Propagation Delay, High-to-Low Level |tPLH - tPHL| Driver Propagation-Delay Skew (Note 2) SYMBOL tDD tTD tPLH tPHL tPDS CONDITIONS RL = 60Ω, Figure 7 RL = 60Ω, Figure 7 RL = 27Ω, Figure 8 RL = 27Ω, Figure 8 RL = 27Ω, Figure 8 MIN TYP MAX UNITS 12 1 3 7 7 15 22 11 23 23 -1.4 35 25 35 35 ±8 Mbps ns ns ns ns ns 42 42 35 35 650 650 90 90 80 80 900 900 ns ns ns ns ns ns TYP MAX 42 28 42 42 -6 70 60 75 75 ±12 UNITS Mbps ns ns ns ns ns 52 52 40 40 700 700 100 100 80 80 1000 1000 ns ns ns ns ns ns DRIVER-OUTPUT ENABLE/DISABLE TIMES (MAX3485E/MAX3491E only) Driver-Output Enable Time to Low Level Driver-Output Enable Time to High Level Driver-Output Disable Time from High Level Driver-Output Disable Time from Low Level Driver-Output Enable Time from Shutdown to Low Level Driver-Output Enable Time from Shutdown to High Level tPZL tPZH tPHZ tPLZ tPSL tPSH RL = 110Ω, Figure 10 RL = 110Ω, Figure 9 RL = 110Ω, Figure 9 RL = 110Ω, Figure 10 RL = 110Ω, Figure 10 RL = 110Ω, Figure 9 DRIVER SWITCHING CHARACTERISTICS—MAX3486E (VCC = +3.3V, TA = +25°C.) PARAMETER Maximum Data Rate Driver Differential Output Delay Driver Differential Output Transition Time Driver Propagation Delay, Low-to-High Level Driver Propagation Delay, High-to-Low Level SYMBOL CONDITIONS |tPLH - tPHL| Driver Propagation-Delay Skew (Note 2) tDD tTD tPLH tPHL tPDS RL = 60Ω, Figure 7 RL = 60Ω, Figure 7 RL = 27Ω, Figure 8 RL = 27Ω, Figure 8 RL = 27Ω, Figure 8 DRIVER-OUTPUT ENABLE/DISABLE TIMES Driver-Output Enable Time to Low Level Driver-Output Enable Time to High Level Driver-Output Disable Time from High Level Driver-Output Disable Time from Low Level Driver-Output Enable Time from Shutdown to Low Level Driver-Output Enable Time from Shutdown to High Level tPZL tPZH tPHZ tPLZ tPSL tPSH RL = 110Ω, Figure 10 RL = 110Ω, Figure 9 RL = 110Ω, Figure 9 RL = 110Ω, Figure 10 RL = 110Ω, Figure 10 RL = 110Ω, Figure 9 MIN 2.5 20 15 20 20 _______________________________________________________________________________________ 3 MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers DRIVER SWITCHING CHARACTERISTICS—MAX3483E/MAX3488E (VCC = +3.3V, TA = +25°C.) PARAMETER SYMBOL CONDITIONS Maximum Data Rate MIN TYP MAX 250 UNITS kbps Driver Differential Output Delay tDD RL = 60Ω, Figure 7 600 900 1400 ns Driver Differential Output Transition Time tTD RL = 60Ω, Figure 7 400 740 1200 ns Driver Propagation Delay, Low-to-High Level tPLH RL = 27Ω, Figure 8 700 930 1500 ns Driver Propagation Delay, High-to-Low Level tPHL RL = 27Ω, Figure 8 700 930 1500 ns |tPLH - tPHL| Driver Propagation-Delay Skew (Note 2) tPDS RL = 27Ω, Figure 8 ±50 ns DRIVER-OUTPUT ENABLE/DISABLE TIMES (MAX3483E only) Driver-Output Enable Time to Low Level tPZL RL = 110Ω, Figure 10 900 1300 ns Driver-Output Enable Time to High Level tPZH RL = 110Ω, Figure 9 600 800 ns Driver-Output Disable Time from High Level tPHZ RL = 110Ω, Figure 9 50 80 ns Driver-Output Disable Time from Low Level tPLZ RL = 110Ω, Figure 10 50 80 ns Driver-Output Enable Time from Shutdown to Low Level tPSL RL = 110Ω, Figure 10 1.9 2.7 µs Driver-Output Enable Time from Shutdown to High Level tPSH RL = 110Ω, Figure 9 2.2 3.0 µs MIN TYP MAX MAX3483E/MAX3485E/MAX3486E/MAX3491E only (Note 3) 80 190 300 VID = 0 to 3.0V, CL = 15pF, Figure 11 25 62 90 MAX3483E/MAX3488E 25 75 120 VID = 0 to 3.0V, CL = 15pF, Figure 11 25 62 90 MAX3483E/MAX3488E 25 75 120 VID = 0 to 3.0V, CL = 15pF, Figure 11 6 ±10 MAX3483E/MAX3488E 12 ±20 RECEIVER SWITCHING CHARACTERISTICS (VCC = +3.3V, TA = +25°C.) PARAMETER SYMBOL Time to Shutdown tSHDN Receiver Propagation Delay, Low-to-High Level tRPLH Receiver Propagation Delay, High-to-Low Level tRPHL |tPLH - tPHL| Receiver tRPDS Propagation-Delay Skew CONDITIONS UNITS ns ns ns ns Receiver-Output Enable Time to Low Level tPRZL CL = 15pF, Figure 12, MAX3483E/85E/86E/91E only 25 50 ns Receiver-Output Enable Time to High Level tPRZH CL = 15pF, Figure 12, MAX3483E/85E/86E/91E only 25 50 ns Receiver-Output Disable Time from High Level tPRHZ CL = 15pF, Figure 12, MAX3483E/85E/86E/91E only 25 45 ns Receiver-Output Disable Time from Low Level tPRLZ CL = 15pF, Figure 12, MAX3483E/85E/86E/91E only 25 45 ns Receiver-Output Enable Time from Shutdown to Low Level tPRSL CL = 15pF, Figure 12, MAX3483E/85E/86E/91E only 720 1400 ns Receiver-Output Enable Time from Shutdown to High Level tPRSH CL = 15pF, Figure 12, MAX3483E/85E/86E/91E only 720 1400 ns Note 1: ∆VOD and ∆VOC are the changes in VOD and VOC, respectively, when the DI input changes state. Note 2: Measured on |tPLH (Y) - tPHL (Y)| and |tPLH (Z) - tPHL (Z)|. Note 3: The transceivers are put into shutdown by bringing RE high and DE low. If the inputs are in this state for less than 80ns, the devices are guaranteed not to enter shutdown. If the inputs are in this state for at least 300ns, the devices are guaranteed to have entered shutdown. See Low-Power Shutdown Mode section. 4 _______________________________________________________________________________________ 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers -18 OUTPUT CURRENT (mA) 15 10 3.30 -14 -12 -10 -8 -6 -4 5 IRO = 1.5mA 3.25 OUTPUT HIGH VOLTAGE (V) -16 20 OUTPUT CURRENT (mA) RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE MAX3483E-02 -20 MAX3483E-01 25 OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE MAX3483E-03 OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE 3.20 3.15 3.10 3.05 -2 0 0.5 1.0 1.5 2.0 2.5 3.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 -20 0 20 40 60 80 OUTPUT HIGH VOLTAGE (V) TEMPERATURE (°C) RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE 90 80 OUTPUT CURRENT (mA) 0.6 0.5 0.4 0.3 0.2 70 60 50 40 30 20 10 0 0 -20 0 20 40 60 80 1.0 1.5 2.0 2.5 3.0 3.5 DIFFERENTIAL OUTPUT VOLTAGE (V) 2.1 2.0 1.9 1.8 -40 -20 0 20 40 60 80 100 OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGE MAX3483E-07 -100 -80 OUTPUT CURRENT (mA) OUTPUT CURRENT (mA) 2.2 TEMPERATURE (°C) OUTPUT CURRENT vs. DRIVER OUTPUT LOW VOLTAGE 150 2.3 1.6 0.5 TEMPERATURE (°C) 175 2.4 1.7 0 100 R = 54Ω 2.5 100 MAX3483E-08 0.1 2.6 DIFFERENTIAL OUTPUT VOLTAGE (V) 0.7 100 MAX3483E-05 IRO = 2.5mA -40 -40 OUTPUT LOW VOLTAGE (V) 0.8 OUTPUT LOW VOLTAGE (V) 3.00 0 3.5 MAX3483E-04 0 MAX3483E-06 0 125 100 75 50 -60 -40 -20 25 0 0 0 2 4 6 8 OUTPUT LOW VOLTAGE (V) 10 12 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 OUTPUT HIGH VOLTAGE (V) 4 5 _______________________________________________________________________________________ 5 MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E Typical Operating Characteristics (VCC = +3.3V, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +3.3V, TA = +25°C, unless otherwise noted.) SHUTDOWN CURRENT vs. TEMPERATURE SUPPLY CURRENT vs. TEMPERATURE X = DON’T CARE 90 SHUTDOWN CURRENT (nA) 1.1 DE = VCC, RE = X 1.0 MAX3483E-10 100 MAX3483E-09 1.2 SUPPLY CURRENT (mA) MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers DE = 0, RE = 0 0.9 80 70 60 50 40 30 20 0.8 10 0.7 0 -40 -20 0 20 40 60 80 -40 100 -20 0 20 40 60 80 100 TEMPERATURE (°C) TEMPERATURE (°C) Pin Description PIN 6 MAX3483E MAX3485E MAX3486E MAX3488E MAX3490E MAX3491E 1 2 2 — NAME FUNCTION 2 RO Receiver Output. If A > B by 200mV, RO will be high; if A < B by 200mV, RO will be low. 3 RE Receiver Output Enable. RO is enabled when RE is low; RO is high impedance when RE is high. If RE is high and DE is low, the device will enter a low-power shutdown mode. 3 — 4 DE Driver Output Enable. The driver outputs are enabled by bringing DE high. They are high impedance when DE is low. If RE is high and DE is low, the device will enter a low-power shutdown mode. If the driver outputs are enabled, the parts function as line drivers. While they are high impedance, they function as line receivers if RE is low. 4 3 5 DI Driver Input. A low on DI forces output Y low and output Z high. Similarly, a high on DI forces output Y high and output Z low. 5 4 6, 7 GND — 5 9 Y Noninverting Driver Output — 6 10 Z Inverting Driver Output 6 — — A Noninverting Receiver Input and Noninverting Driver Output — 8 12 A Noninverting Receiver Input 7 — — B Inverting Receiver Input and Inverting Driver Output — 7 11 B Inverting Receiver Input 8 1 13, 14 VCC Positive Supply: 3.0V ≤ VCC ≤ 3.6V. Do not operate device with VCC > 3.6V. — — 1, 8 N.C. No Connection. Not internally connected. Ground _______________________________________________________________________________________ 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E TOP VIEW R 1 8 VCC RO RE 2 7 B RE 2 DE 3 6 A DE 3 5 GND DI 4 RO 1 DI 4 D R 8 VCC 7 B Rt 6 A 5 GND D DE MAX3483E MAX3485E MAX3486E D DI B Rt A RO R RE SO/DIP NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH. Figure 1. MAX3483E/MAX3485E/MAX3486E Pin Configuration and Typical Operating Circuit VCC VCC TOP VIEW MAX3488E MAX3490E 1 5 Y 8 A RO 2 7 B DI 3 6 Z VCC 1 GND 4 R 5 D DI 3 Rt D 6 Z R RO 8 A RO Y 2 Rt R D 7 DI B SO/DIP 4 GND GND Figure 2. MAX3488E/MAX3490E Pin Configuration and Typical Operating Circuit TOP VIEW DE VCC 4 N.C. 1 RO 2 14 VCC R 13 VCC RE 3 12 A DE 4 11 B DI 5 GND 6 10 Z D GND 7 SO/DIP 9 Y 8 N.C. VCC RE 9 DI 5 MAX3491E 13, 14 Y Rt D 10 RO R Z 12 RO 2 R A Rt D 11 DI B N.C. 1, 8 3 6, 7 RE GND GND DE Figure 3. MAX3491E Pin Configuration and Typical Operating Circuit _______________________________________________________________________________________ 7 MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers 375Ω RL 2 VOD D D RL VCC 2 VOC VCC Figure 4. Driver VOD and VOC VID VCM = -7V to +12V RL VOD 375Ω Figure 5. Driver VOD with Varying Common-Mode Voltage R 0 VOL IOL (+) VOH IOH (-) Figure 6. Receiver VOH and VOL 3V IN 1.5V 1.5V CL D GENERATOR (NOTE 4) 0 RL = 60Ω OUT tDD tDD ≈ 2.0V 50Ω 90% VCC OUT CL CL = 15pF (NOTE 5) 50% 10% 90% 50% 10% tTD Figure 7. Driver Differential Output Delay and Transition Times 8 _______________________________________________________________________________________ tTD ≈ -2.0V 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3V VOM IN 1.5V 1.5V RL = 27Ω 0V S1 GENERATOR (NOTE 4) tPLH OUT D 50Ω CL = 15pF (NOTE 5) VCC tPHL VOH Y OUT VOM VOM VOL VOM = VOH + VOL 2 tPHL ≈ 1.5V tPLH VOH Z OUT VOM VOM VOL Figure 8. Driver Propagation Times 3V S1 0 OR 3V OUT D IN 1.5V 1.5V 0 GENERATOR (NOTE 4) RL = 110Ω CL = 50pF (NOTE 5) tPZH tPHZ 50Ω 0.25V OUT VOM = VOH + VOL 2 VOH VOM ≈ 1.5V 0 Figure 9. Driver Enable and Disable Times (tPZH, tPSH, tPHZ) VCC 3V RL = 110Ω S1 0 OR 3V IN 1.5V 1.5V 0 OUT D tPSL tPLZ CL = 50pF (NOTE 5) GENERATOR (NOTE 4) VCC OUT 50Ω VOM 0.25V VOL Figure 10. Driver Enable and Disable Times (tPZL, tPSL, tPLZ) _______________________________________________________________________________________ 9 MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers 3.0V GENERATOR (NOTE 4) VID OUT R IN 50Ω 1.5V 1.5V CL = 15pF (NOTE 5) 0 tRPLH tRPHL VCC 1.5V VOM = 0 VOM OUT VCC 2 VOM 0 Figure 11. Receiver Propagation Delay S1 S3 1.5V VCC 1k -1.5V VID R S2 CL (NOTE 5) GENERATOR (NOTE 4) 50Ω 3V IN 1.5V 0 3V S1 OPEN S2 CLOSED S3 = 1.5V IN 1.5V 0 tPRZH tPRSH tPRZL tPRSL VOH OUT VCC OUT 1.5V 1.5V 0 VOL 3V IN 1.5V 0 3V S1 OPEN S2 CLOSED S3 = 1.5V IN 1.5V 0 tPRHZ OUT 0.25V S1 CLOSED S2 OPEN S3 = -1.5V S1 CLOSED S2 OPEN S3 = -1.5V tPRLZ VOH VCC OUT 0 0.25V VOL Figure 12. Receiver Enable and Disable Times Note 4: The input pulse is supplied by a generator with the following characteristics: f = 250kHz, 50% duty cycle, t r ≤ 6.0ns, ZO = 50Ω. Note 5: CL includes probe and stray capacitance. 10 ______________________________________________________________________________________ 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers ___________Applications Information Devices with Receiver/Driver Enable (MAX3483E/MAX3485E/MAX3486E/MAX3491E) The MAX3483E/MAX3485E/MAX3486E/MAX3488E/ MAX3490E/MAX3491E are low-power transceivers for RS-485 and RS-422 communications. The MAX3483E and MAX3488E can transmit and receive at data rates up to 250kbps, the MAX3486E at up to 2.5Mbps, and the MAX3485E/MAX3490E/MAX3491E at up to 12Mbps. The MAX3488E/MAX3490E/MAX3491E are full-duplex transceivers, while the MAX3483E/MAX3485E/MAX3486E are half-duplex. Driver Enable (DE) and Receiver Enable (RE) pins are included on the MAX3483E/MAX3485E/ MAX3486E/MAX3491E. When disabled, the driver and receiver outputs are high impedance. Table 1. Transmitting INPUTS OUTPUTS MODE RE DE DI B* A* X 1 1 0 1 Normal X 1 0 1 0 Normal 0 0 X High-Z High-Z Normal 1 0 X High-Z High-Z Shutdown * B and A outputs are Z and Y, respectively, for full-duplex part (MAX3491E). X = Don’t care; High-Z = High impedance Table 2. Receiving INPUTS OUTPUTS MODE RE DE A, B RO 0 0* ≥ +0.2V 1 Normal 0 0* ≤ -0.2V 0 Normal 0 0* Inputs Open 1 Normal 1 0 X High-Z Shutdown * DE is a “don’t care” (x) for the full-duplex part (MAX3491E). X = Don’t care; High-Z = High impedance Devices without Receiver/Driver Enable (MAX3488E/MAX3490E) Table 3. Transmitting INPUT Table 4. Receiving INPUTS OUTPUT DI OUTPUTS Z Y A, B RO 1 0 1 ≥ +0.2V 1 0 1 0 ≤ -0.2V 0 Inputs Open 1 10dB/div Reduced EMI and Reflections (MAX3483E/MAX3486E/MAX3488E) The MAX3483E/MAX3488E are slew-rate limited, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 13 shows the driver output waveform of a MAX3485E/MAX3490E/MAX3491E transmitting a 125kHz signal, as well as the Fourier analysis of that waveform. High-frequency harmonics with large amplitudes are evident. Figure 14 shows the same information, but for the slew-rate-limited MAX3483E/MAX3488E transmitting the same signal. The high-frequency harmonics have much lower amplitudes, and the potential for EMI is significantly reduced. Low-Power Shutdown Mode (MAX3483E/MAX3485E/MAX3486E/MAX3491E) A low-power shutdown mode is initiated by bringing both RE high and DE low. The devices will not shut down unless both the driver and receiver are disabled (high impedance). In shutdown, the devices typically draw only 2nA of supply current. For these devices, the t PSH and t PSL enable times assume the part was in the low-power shutdown mode; the tPZH and tPZL enable times assume the receiver or driver was disabled, but the part was not shut down. 10dB/div 0 500kHz/div 5MHz Figure 13. Driver Output Waveform and FFT Plot of MAX3485E/ MAX3490E/MAX3491E Transmitting a 125kHz Signal 0 500kHz/div 5MHz Figure 14. Driver Output Waveform and FFT Plot of MAX3483E/ MAX3488E Transmitting a 125kHz Signal ______________________________________________________________________________________ 11 MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E _____________________Function Tables MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers B 1V/div DI 2V/div A 1V/div Z 1V/div RO 2V/div Y 1V/div 20ns/div Figure 15. MAX3485E/MAX3490E/MAX3491E Driver Propagation Delay 20ns/div Figure 16. MAX3485E/MAX3490E/MAX3491E Receiver Propagation Delay Driven by External RS-485 Device B 1V/div DI 2V/div A 1V/div Z 1V/div Y 1V/div RO 2V/div 1µs/div 1µs/div Figure 17. MAX3483E/MAX3488E Driver Propagation Delay DI 5V/div DI 5V/div VY - VZ 2V/div VY - VZ 2V/div RO 5V/div RO 5V/div 2µs/div Figure 19. MAX3483E/MAX3488E System Differential Voltage at 125kHz Driving 4000 Feet of Cable 12 Figure 18. MAX3483E/MAX3488E Receiver Propagation Delay 2µs/div Figure 20. MAX3485E/MAX3490E/MAX3491E System Differential Voltage at 125kHz Driving 4000 Feet of Cable ______________________________________________________________________________________ 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers ±15kV 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 MAX3483E family of devices have extra protection against static electricity. Maxim’s engineers have developed state-ofthe-art structures to protect these pins against ESD of ±15kV without damage. The ESD structures withstand high ESD in all states: normal operation, shutdown, and powered down. After an ESD event, Maxim’s E versions keep working without latchup or damage. ESD protection can be tested in various ways; the transmitter outputs and receiver inputs of this product family are characterized for protection to the following limits: 1) ±15kV using the Human Body Model Propagation Delay Figures 15–18 show the typical propagation delays. Skew time is simply the difference between the low-to-high and high-to-low propagation delay. Small driver/receiver skew times help maintain a symmetrical mark-space ratio (50% duty cycle). The receiver skew time, |tPRLH - tPRHL|, is under 10ns (20ns for the MAX3483E/MAX3488E). The driver skew times are 8ns for the MAX3485E/MAX3490E/MAX3491E, 12ns for the MAX3486E, and typically under 50ns for the MAX3483E/MAX3488E. Line Length vs. Data Rate The RS-485/RS-422 standard covers line lengths up to 4000 feet. For line lengths greater than 4000 feet, see Figure 21 for an example of a line repeater. Figures 19 and 20 show the system differential voltage for parts driving 4000 feet of 26AWG twisted-pair wire at 125kHz into 120Ω loads. For faster data rate transmission, please consult the factory. MAX3488E MAX3490E MAX3491E A RO RE DE R 120Ω B DATA IN Z DI D 120Ω Y DATA OUT NOTE: RE AND DE ON MAX3491E ONLY. Figure 21. Line Repeater for MAX3488E/MAX3490E/MAX3491E 2) ±8kV using the Contact-Discharge method specified in IEC 1000-4-2 3) ±15kV using IEC 1000-4-2’s Air-Gap method. 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 22a shows the Human Body Model and Figure 22b 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 1.5kΩ resistor. IEC 1000-4-2 The IEC 1000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically refer to integrated circuits. The MAX3483E family of devices helps you design equipment that meets Level 4 (the highest level) of IEC 1000-4-2, without the need for additional ESD-protection components. The major difference between tests done using the Human Body Model and IEC 1000-4-2 is higher peak current in IEC 1000-4-2, because series resistance is lower in the IEC 1000-4-2 model. Hence, the ESD withstand voltage measured to IEC 1000-4-2 is generally lower than that measured using the Human Body Model. Figure 23a shows the IEC 1000-4-2 model, and Figure 23b shows the current waveform for the ±8kV IEC 1000-4-2, Level 4 ESD contact-discharge test. ______________________________________________________________________________________ 13 MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E Driver-Output Protection Excessive output current and power dissipation caused by faults or by bus contention are prevented by two mechanisms. A foldback current limit on the output stage provides immediate protection against short circuits over the whole common-mode voltage range (see Typical Operating Characteristics). In addition, a thermal shutdown circuit forces the driver outputs into a high-impedance state if the die temperature rises excessively. RC 1M CHARGE-CURRENT LIMIT RESISTOR RD 1500Ω IP 100% 90% DISCHARGE RESISTANCE Ir PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) AMPERES HIGHVOLTAGE DC SOURCE Cs 100pF STORAGE CAPACITOR DEVICE UNDER TEST 36.8% 10% 0 0 tDL CURRENT WAVEFORM Figure 22b. Human Body Current Waveform Figure 22a. Human Body ESD Test Model RC 50M to 100M TIME tRL RD 330Ω I 100% CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 150pF DISCHARGE RESISTANCE STORAGE CAPACITOR 90% DEVICE UNDER TEST I PEAK MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers 10% Figure 23a. IEC 1000-4-2 ESD Test Model t r = 0.7ns to 1ns t 30ns 60ns Figure 23b. IEC 1000-4-2 ESD Generator Current Waveform The air-gap test involves approaching the device with a charged probe. The contact-discharge method connects the probe to the device before the probe is energized. Machine Model The Machine Model for ESD tests all pins using a 200pF storage capacitor and zero discharge resistance. Its objective is to emulate the stress caused when I/O pins are contacted by handling equipment during test and assembly. Of course, all pins require this protection, not just RS-485 inputs and outputs. 14 Typical Applications The MAX3483E/MAX3485E/MAX3486E/MAX3488E/ MAX3490E/MAX3491E transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figures 24 and 25 show typical network applications circuits. These parts can also be used as line repeaters, with cable lengths longer than 4000 feet, as shown in Figure 21. To minimize reflections, the line should be terminated at both ends in its characteristic impedance, and stub lengths off the main line should be kept as short as possible. The slew-rate-limited MAX3483E/MAX3488E and the partially slew-rate-limited MAX3486E are more tolerant of imperfect termination. ______________________________________________________________________________________ 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers DI MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 120Ω 120Ω DE B B D D DI DE B A A B A A R R RO RE RO RE R R D D MAX3483E MAX3485E MAX3486E DE DI RO RE DI RO RE DE Figure 24. MAX3483E/MAX3485E/MAX3486E Typical RS-485 Network A R RO RE Y 120Ω 120Ω D B Z Z B DE DI DI DE 120Ω D Y 120Ω Z Y B A Y Z R A DE RE RO A R D D DI B R RE RO DI MAX3488E MAX3490E MAX3491E DE RE RO NOTE: RE AND DE ON MAX3491E ONLY. Figure 25. MAX3488E/MAX3490E/MAX3491E Full-Duplex RS-485 Network ______________________________________________________________________________________ 15 MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3.3V-Powered, ±15kV ESD-Protected, 12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers Ordering Information (continued) PART TEMP. RANGE MAX3486ECSA 0°C to +70°C 8 SO PIN-PACKAGE MAX3486ECPA 0°C to +70°C 8 Plastic DIP MAX3486EESA MAX3486EEPA MAX3488ECSA -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO 8 Plastic DIP 8 SO MAX3488ECPA 0°C to +70°C 8 Plastic DIP MAX3488EESA MAX3488EEPA MAX3490ECSA -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO 8 Plastic DIP 8 SO MAX3490ECPA 0°C to +70°C 8 Plastic DIP MAX3490EESA MAX3490EEPA MAX3491ECSD -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO 8 Plastic DIP 14 SO MAX3491ECPD 0°C to +70°C 14 Plastic DIP MAX3491EESD MAX3491EEPD -40°C to +85°C -40°C to +85°C 14 SO 14 Plastic DIP Chip Information TRANSISTOR COUNT: 761 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. 16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.