19-0333; Rev 0; 12/94 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers The MAX3483, MAX3485, MAX3486, MAX3488, MAX3490, and MAX3491 are 3.3V, low-power transceivers for RS-485 and RS-422 communication. Each part contains one driver and one receiver. The MAX3483 and MAX3488 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 MAX3486 transmits up to 2.5Mbps. The MAX3485, MAX3490, and MAX3491 transmit at up to 10Mbps. 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 MAX3488, MAX3490, and MAX3491 feature fullduplex communication, while the MAX3483, MAX3485, and MAX3486 are designed for half-duplex communication. ____________________________Features ♦ Operate from a Single 3.3V Supply— No Charge Pump! ♦ Interoperable with +5V Logic ♦ 8ns Max Skew (MAX3485/MAX3490/MAX3491) ♦ Slew-Rate Limited for Errorless Data Transmission (MAX3483/MAX3488) ♦ 2nA Low-Current Shutdown Mode (MAX3483/MAX3485/MAX3486/MAX3491) ♦ -7V to +12V Common-Mode Input Voltage Range ♦ Allows up to 32 Transceivers on the Bus ♦ Full-Duplex and Half-Duplex Versions Available ♦ Industry Standard 75176 Pinout (MAX3483/MAX3485/MAX3486) ♦ Current-Limiting and Thermal Shutdown for Driver Overload Protection ______________Ordering Information ________________________Applications Low-Power RS-485/RS-422 Transceivers Telecommunications Transceivers for EMI-Sensitive Applications Industrial-Control Local Area Networks PART TEMP. RANGE MAX3483CPA 0°C to +70°C 8 Plastic DIP PIN-PACKAGE MAX3483CSA MAX3483C/D MAX3483EPA MAX3483ESA MAX3485CPA 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO Dice* 8 Plastic DIP 8 SO 8 Plastic DIP MAX3485CSA MAX3485C/D MAX3485EPA MAX3485ESA 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 8 SO Dice* 8 Plastic DIP 8 SO Ordering Information continued at end of data sheet. * Contact factory for for dice specifications. ______________________________________________________________Selection Table PART NUMBER GUARANTEED DATA RATE (Mbps) MAX3483 MAX3485 SUPPLY VOLTAGE (V) HALF/FULL DUPLEX SLEW-RATE LIMITED DRIVER/ RECEIVER ENABLE SHUTDOWN CURRENT (nA) PIN COUNT 0.25 Half Yes Yes 2 8 10 Half No Yes 2 8 Half Yes Yes 2 8 Full Yes No — 8 MAX3486 2.5 MAX3488 0.25 MAX3490 10 Full No No — 8 MAX3491 10 Full No Yes 2 14 3.0 to 3.6 ________________________________________________________________ Maxim Integrated Products Call toll free 1-800-998-8800 for free samples or literature. 1 MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 _______________General Description MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 3.3V-Powered, 10Mbps 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 Plastic DIP (derate 9.09mW/°C above +70°C) .....727mW 8-Pin SO (derate 5.88mW/°C above +70°C)..................471mW 14-Pin Plastic DIP (derate 10mW/°C above +70°C) ......800mW 14-Pin SO (derate 8.33mW/°C above +70°C)................667mW Operating Temperature Ranges MAX34_ _C_ _.......................................................0°C to +70°C MAX34_ _E_ _ ....................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +160°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 MIN RL = 100Ω (RS-422), Figure 4 2.0 RL = 54Ω (RS-485), Figure 4 1.5 RL = 60Ω (RS-485), VCC = 3.3V, Figure 5 1.5 TYP MAX 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 2.0 0.8 V V Logic Input Current IIN1 DE, DI, RE ±2 µA Input Current (A, B) IIN2 DE = 0V, VCC = 0V or 3.6V VIN = 12V 1.0 VIN = -7V -0.8 Output Leakage (Y, Z) IO VOUT = 12V DE = 0V, RE = 0V, VCC = 0V or 3.6V, MAX3491 VOUT = -7V -20 Output Leakage (Y, Z) in Shutdown Mode IO VOUT = 12V DE = 0V, RE = VCC, VCC = 0V or 3.6V, MAX3491 VOUT = -7V -1 Receiver Differential Threshold Voltage VTH -7V ≤ VCM ≤ 12V 20 1 -0.2 0.2 mA µA µA V Receiver Input Hysteresis ∆VTH VCM = 0V 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, 0V ≤ VOUT ≤ VCC ±1 µA Receiver Input Resistance RIN -7V ≤ VCM ≤ 12V 2 50 mV VCC - 0.4 12 _______________________________________________________________________________________ V kΩ 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 DC ELECTRICAL CHARACTERISTICS (continued) (VCC = 3.3V ±0.3V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C) PARAMETER Supply Current SYMBOL ICC Supply Current in Shutdown Mode ISHDN Driver Short-Circuit Output Current IOSD Receiver Short-Circuit Output Current IOSR CONDITIONS No load, DI = 0V or VCC MIN TYP MAX DE = VCC, RE = 0V or VCC 1.1 2.2 DE = 0V, RE = 0V 0.95 mA DE = 0V, RE = VCC, DI = VCC or 0V 0.002 1.9 1 VOUT = -7V -250 VOUT = 12V 250 0V ≤ VRO ≤ VCC UNITS ±8 ±60 µA mA mA DRIVER SWITCHING CHARACTERISTICS—MAX3485, MAX3490, and MAX3491 (VCC = 3.3V, TA = +25°C) MIN TYP MAX Driver Differential Output Delay PARAMETER SYMBOL tDD RL = 60Ω, Figure 7 CONDITIONS 1 22 35 ns Driver Differential Output Transition Time tTD RL = 60Ω, Figure 7 3 8 25 ns Driver Propagation Delay, Low-to-High Level tPLH RL = 27Ω, Figure 8 7 22 35 ns Driver Propagation Delay, High-to-Low Level tPHL RL = 27Ω, Figure 8 7 22 35 ns 8 ns tPDS RL = 27Ω, Figure 8 |tPLH - tPHL| Driver Propagation Delay Skew (Note 2) DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3485/MAX3491 only) UNITS Driver Output Enable Time to Low Level tPZL RL = 110Ω, Figure 10 45 90 ns Driver Output Enable Time to High Level tPZH RL = 110Ω, Figure 9 45 90 ns Driver Output Disable Time from High Level tPHZ RL = 110Ω, Figure 9 40 80 ns Driver Output Disable Time from Low Level tPLZ RL = 110Ω, Figure 10 40 80 ns Driver Output Enable Time from Shutdown to Low Level tPSL RL = 110Ω, Figure 10 650 900 ns Driver Output Enable Time from Shutdown to High Level tPSH RL = 110Ω, Figure 9 650 900 ns DRIVER SWITCHING CHARACTERISTICS—MAX3486 (VCC = 3.3V, TA = +25°C) MIN TYP MAX Driver Differential Output Delay PARAMETER SYMBOL tDD RL = 60Ω, Figure 7 CONDITIONS 24 48 70 UNITS ns Driver Differential Output Transition Time tTD RL = 60Ω, Figure 7 15 35 60 ns Driver Propagation Delay, Low-to-High Level tPLH RL = 27Ω, Figure 8 20 48 70 ns Driver Propagation Delay, High-to-Low Level tPHL RL = 27Ω, Figure 8 20 48 |tPLH - tPHL| Driver Propagation Delay Skew (Note 2) tPDS RL = 27Ω, Figure 8 Driver Output Enable Time to Low Level tPZL RL = 110Ω, Figure 10 Driver Output Enable Time to High Level tPZH Driver Output Disable Time from High Level Driver Output Disable Time from Low Level 70 ns 11 ns 55 100 ns RL = 110Ω, Figure 9 55 100 ns tPHZ RL = 110Ω, Figure 9 45 80 ns tPLZ RL = 110Ω, Figure 10 45 80 ns Driver Output Enable Time from Shutdown to Low Level tPSL RL = 110Ω, Figure 10 700 1000 ns Driver Output Enable Time from Shutdown to High Level tPSH RL = 110Ω, Figure 9 700 1000 ns _______________________________________________________________________________________ 3 MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers DRIVER SWITCHING CHARACTERISTICS—MAX3483 and MAX3488 (VCC = 3.3V, TA = +25°C) MIN TYP Driver Differential Output Delay PARAMETER SYMBOL tDD RL = 60Ω, Figure 7 CONDITIONS 600 900 MAX 1400 UNITS ns Driver Differential Output Transition Time tTD RL = 60Ω, Figure 7 400 700 1200 ns Driver Propagation Delay, Low-to-High Level tPLH RL = 27Ω, Figure 8 700 1000 1500 ns Driver Propagation Delay, High-to-Low Level tPHL RL = 27Ω, Figure 8 700 1000 1500 ns tPDS |tPLH - tPHL| Driver Propagation Delay Skew (Note 2) DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3483 only) RL = 27Ω, Figure 8 100 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 MAX3483/MAX3485/MAX3486/MAX3491 only (Note 3) 80 190 300 VID = 0V to 3.0V, CL = 15pF, Figure 11 25 65 90 MAX3483/MAX3488 25 75 120 VID = 0V to 3.0V, CL = 15pF, Figure 11 25 65 90 MAX3483/MAX3488 25 75 120 ns RECEIVER SWITCHING CHARACTERISTICS (VCC = 3.3V, TA = +25°C) PARAMETER SYMBOL CONDITIONS UNITS Time to Shutdown tSHDN Receiver Propagation Delay, Low-to-High Level tRPLH Receiver Propagation Delay, High-to-Low Level tRPHL |tPLH - tPHL| Receiver Propagation Delay Skew tRPDS Receiver Output Enable Time to Low Level tPRZL CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only 25 50 ns Receiver Output Enable Time to High Level tPRZH CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only 25 50 ns Receiver Output Disable Time from High Level tPRHZ CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only 25 45 ns Receiver Output Disable Time from Low Level tPRLZ CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only 25 45 ns Receiver Output Enable Time from Shutdown to Low Level tPRSL CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only 720 1400 ns Receiver Output Enable Time from Shutdown to High Level tPRSH CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only 720 1400 ns VID = 0V to 3.0V, CL = 15pF, Figure 11 10 MAX3483/MAX3488 20 ns ns ns 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 parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 300ns, the parts are guaranteed to have entered shutdown. See Low-Power Shutdown Mode section. 4 _______________________________________________________________________________________ 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers 15 10 OUTPUT HIGH VOLTAGE (V) -18 OUTPUT CURRENT (mA) 20 -16 -14 -12 -10 -8 -6 -4 5 3.30 MAX3483-02 -20 MAX3483-01 25 OUTPUT CURRENT (mA) RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE IRO = 1.5mA MAX3483-03 OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE 3.25 3.20 3.15 3.10 3.05 -2 0 1.0 1.5 2.0 2.5 3.0 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT HIGH VOLTAGE (V) RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE 100 90 OUTPUT CURRENT (mA) 0.7 0.6 0.5 0.4 0.3 0.2 80 70 60 50 40 30 20 0.1 10 0 0 0 20 40 60 80 100 0.5 TEMPERATURE (°C) 1.0 1.5 2.0 2.5 3.0 DIFFERENTIAL OUTPUT VOLTAGE (V) OUTPUT CURRENT vs. DRIVER OUTPUT LOW VOLTAGE 20 40 60 80 100 2.6 R = 54Ω 2.5 2.4 2.3 2.2 2.1 2.0 1.9 1.8 1.7 3.5 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGE -100 MAX3483-07 OUTPUT CURRENT (mA) 150 0 1.6 0 175 -20 125 100 75 50 MAX3483-08 -20 OUTPUT CURRENT (mA) -40 -40 DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs.TEMPERATURE MAX3483-05 IRO = 2.5mA 3.5 TEMPERATURE (°C) OUTPUT LOW VOLTAGE (V) 0.8 OUTPUT LOW VOLTAGE (V) 3.00 0 3.5 MAX3483-06 0.5 MAX3483-04 0 DIFFERENTIAL OUTPUT VOLTAGE (V) 0 -80 -60 -40 -20 25 0 0 0 2 4 6 8 10 OUTPUT LOW VOLTAGE (V) 12 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 OUTPUT HIGH VOLTAGE (V) 4 5 _______________________________________________________________________________________ 5 MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 __________________________________________Typical Operating Characteristics (VCC = 3.3V, TA = +25°C, unless otherwise noted.) _____________________________Typical Operating Characteristics (continued) SHUTDOWN CURRENT vs. TEMPERATURE SUPPLY CURRENT vs. TEMPERATURE 90 1.1 DE = VCC, RE = X 1.0 MAX3483-10 100 SHUTDOWN CURRENT (nA) X = DON’T CARE MAX3483-09 1.2 SUPPLY CURRENT (mA) MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers DE = 0, RE = 0 0.9 0.8 80 70 60 50 40 30 20 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 MAX3483/ MAX3485/ MAX3486 MAX3488/ MAX3490 MAX3491 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 — — 1, 8 N.C. No Connect—not internally connected Ground _______________________________________________________________________________________ 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 TOP VIEW RO 1 RE 2 DE 3 DI 4 R D 1 VCC RO 7 B RE 2 6 A DE 3 5 GND DI 4 8 R 8 VCC 7 B Rt 6 A 5 GND D DE MAX3483 MAX3485 MAX3486 D DI B Rt A RO R RE DIP/SO NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH. Figure 1. MAX3483/MAX3485/MAX3486 Pin Configuration and Typical Operating Circuit VCC VCC TOP VIEW MAX3488 MAX3490 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 R Rt D 7 DI B DIP/SO 4 GND GND Figure 2. MAX3488/MAX3490 Pin Configuration and Typical Operating Circuit TOP VIEW DE 4 N.C. 1 RO 2 14 V CC R 13 V CC RE 3 12 A DE 4 11 B DI 5 GND 6 GND 7 10 Z D 5 MAX3491 Y Rt D 10 RO R Z 12 RO 2 R 9 Y 8 N.C. DIP/SO 9 DI VCC RE VCC 13, 14 A Rt D 11 DI B N.C. 1, 8 3 6, 7 RE GND GND DE Figure 3. MAX3491 Pin Configuration and Typical Operating Circuit _______________________________________________________________________________________ 7 MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers 375Ω RL 2 VCM = -7V to +12V VOD D D RL 2 VCC VOD RL VOC VCC Figure 4. Driver VOD and VOC VID 375Ω Figure 5. Driver VOD with Varying Common-Mode Voltage R 0V VOL IOL (+) VOH IOH (-) Figure 6. Receiver VOH and VOL 3V IN 1.5V 1.5V CL D GENERATOR (NOTE 4) 0V RL = 60Ω OUT tDO tDO ≈ 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 ≈ -2.0V 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 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 0V OR 3V OUT D IN 1.5V 1.5V 0V GENERATOR (NOTE 4) RL = 110Ω CL = 50pF (NOTE 5) tPZH tPHZ 50Ω 0.25V OUT VOH + VOL VOM = 2 VOH VOM ≈ 1.5V 0V Figure 9. Driver Enable and Disable Times (tPZH, tPSH, tPHZ) VCC 3V RL = 110Ω S1 0V OR 3V IN 1.5V 1.5V 0V OUT D tPSL GENERATOR (NOTE 4) CL = 50pF (NOTE 5) 50Ω tPLZ VCC OUT VOM 0.25V VOL Figure 10. Driver Enable and Disable Times (tPZL, tPSL, tPLZ) _______________________________________________________________________________________ 9 MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 3.3V-Powered, 10Mbps 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) 0V tRPLH tRPHL VCC 1.5V VOM = 0V VOM OUT VCC 2 VOM 0V Figure 11. Receiver Propagation Delay S1 S3 1.5V 1k -1.5V VID VCC R S2 CL (NOTE 5) GENERATOR (NOTE 4) 50Ω 3V IN 1.5V 0V 3V S1 OPEN S2 CLOSED S3 = 1.5V IN 1.5V 0V tPRZH tPRSH tPRZL tPRSL VOH OUT VCC OUT 1.5V 1.5V 0V VOL 3V IN S1 CLOSED S2 OPEN S3 = -1.5V 1.5V 0V 3V S1 OPEN S2 CLOSED S3 = 1.5V IN 1.5V 0V S1 CLOSED S2 OPEN S3 = -1.5V tPRHZ OUT 0.25V tPRLZ VOH OUT VCC 0.25V 0V VOL Figure 12. Receiver Enable and Disable Times Note 4: The input pulse is supplied by a generator with the following characteristics: PRR = 250kHz, 50% duty cycle, tr ≤ 6.0ns, ZO = 50Ω. Note 5: CL includes probe and stray capacitance. 10 ______________________________________________________________________________________ 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers Devices with Receiver/Driver Enable (MAX3483/MAX3485/MAX3486/MAX3491) 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 __________Applications Information The MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/ MAX3491 are low-power transceivers for RS-485 and RS-422 communications. The MAX3483 and MAX3488 can transmit and receive at data rates up to 250kbps, the MAX3486 at up to 2.5Mbps, and the MAX3485/ MAX3490/MAX3491 at up to 10Mbps. The MAX3488/ MAX3490/MAX3491 are full-duplex transceivers, while the MAX3483/MAX3485/MAX3486 are half-duplex. Driver Enable (DE) and Receiver Enable (RE) pins are included on the MAX3483/MAX3485/MAX3486/ MAX3491. When disabled, the driver and receiver outputs are high impedance. * B and A outputs are Z and Y, respectively, for full-duplex part (MAX3491). 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 (MAX3491). X = Don’t care; High-Z = High impedance Devices without Receiver/Driver Enable (MAX3488/MAX3490) Table 3. Transmitting INPUT Table 4. Receiving OUTPUTS INPUTS OUTPUT DI Z Y A, B RO 1 0 1 ≥ +0.2V 1 0 1 0 ≤ -0.2V 0 Inputs Open 1 10dB/div 0Hz Reduced EMI and Reflections (MAX3483/MAX3486/MAX3488) The MAX3483/MAX3488 are slew-rate limited, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 13 shows both the driver output waveform of a MAX3485/MAX3490/MAX3491 transmitting a 125kHz signal and 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 MAX3483/MAX3488 transmitting the same signal. The high-frequency harmonics have much lower amplitudes, and the potential for EMI is significantly reduced. Low-Power Shutdown Mode (MAX3483/MAX3485/MAX3486/MAX3491) 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 500kHz/div 5MHz Figure 13. Driver Output Waveform and FFT Plot of MAX3485/ MAX3490/MAX3491 Transmitting a 125kHz Signal 0Hz 500kHz/div 5MHz Figure 14. Driver Output Waveform and FFT Plot of MAX3483/ MAX3488 Transmitting a 125kHz Signal ______________________________________________________________________________________ 11 MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 ____________________Function Tables MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 3.3V-Powered, 10Mbps 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 20ns/div Figure 15. MAX3485/MAX3490/MAX3491 Driver Propagation Delay Figure 16. MAX3485/MAX3490/MAX3491 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. MAX3483/MAX3488 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. MAX3483/MAX3488 System Differential Voltage at 125kHz Driving 4000 ft of Cable 12 Figure 18. MAX3483/MAX3488 Receiver Propagation Delay 2µs/div Figure 20. MAX3485/MAX3490/MAX3491 System Differential Voltage at 125kHz Driving 4000 ft of Cable ______________________________________________________________________________________ 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers 120Ω DI DE B D D DI DE RO RE A B A B A A R R RO RE R R D D MAX3483 MAX3485 MAX3486 DI DE RO RE DI DE RO RE Figure 21. MAX3483/MAX3485/MAX3486 Typical RS-485 Network Driver Output Protection Line Length vs. Data Rate 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. The RS-485/RS-422 standard covers line lengths up to 4000 feet. For line lengths greater than 4000 feet, see Figure 23. Figures 19 and 20 show the system differential voltage for parts driving 4000 feet of 26AWG twisted-pair wire at 125kHz into 120Ω loads. 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 MAX3483/MAX3488). The driver skew times are 8ns for the MAX3485/MAX3490/MAX3491, 11ns for the MAX3486, and typically under 100ns for the MAX3483/MAX3488. Typical Applications The MAX3483, MAX3485, MAX3486, MAX3488, MAX3490, and MAX3491 transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figures 21 and 22 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 23. 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 MAX3483/MAX3488 and the partially slew-rate-limited MAX3486 are more tolerant of imperfect termination. ______________________________________________________________________________________ 13 MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 120Ω B MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers A R RO RE Y 120Ω 120Ω D B Z Z B DE DE DI 120Ω D Y 120Ω Z Y B A Y Z R DI B A DE RE RO R A R D D DI MAX3488 MAX3490 MAX3491 DE RE RO NOTE: RE AND DE ON MAX3491 ONLY. Figure 22. MAX3488/MAX3490/MAX3491 Full-Duplex RS-485 Network MAX3488 MAX3490 MAX3491 A RO RE R 120Ω B DATA IN DE Z DI D 120Ω Y DATA OUT NOTE: RE AND DE ON MAX3491 ONLY. Figure 23. Line Repeater for MAX3488/MAX3490/MAX3491 14 DI ______________________________________________________________________________________ RE RO 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers PART TEMP. RANGE MAX3486CPA 0°C to +70°C 8 Plastic DIP MAX3486CSA MAX3486C/D MAX3486EPA MAX3486ESA MAX3488CPA 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO Dice* 8 Plastic DIP 8 SO 8 Plastic DIP MAX3488CSA MAX3488C/D MAX3488EPA MAX3488ESA MAX3490CPA 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO Dice* 8 Plastic DIP 8 SO 8 Plastic DIP MAX3490CSA MAX3490C/D MAX3490EPA MAX3490ESA MAX3491CPD 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO Dice* 8 Plastic DIP 8 SO 14 Plastic DIP MAX3491CSD MAX3491C/D MAX3491EPD MAX3491ESD 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 14 SO Dice* 14 Plastic DIP 14 SO __________________ Chip Topography V CC PIN-PACKAGE RO A RE B Z/B 0.146" (3.71mm) DE DI Y/A GND * Contact factory for for dice specifications. GND 0.086" (2.18mm) TRANSISTOR COUNT: 810 SUBSTRATE CONNECTED TO GROUND ______________________________________________________________________________________ 15 MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 _Ordering Information (continued) MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers ________________________________________________________Package Information DIM D 0°-8° A 0.101mm 0.004in. e B A1 C E L SO SMALL OUTLINE PACKAGE (0.150 in.) H A A1 B C E e H L INCHES MAX MIN 0.069 0.053 0.010 0.004 0.019 0.014 0.010 0.007 0.157 0.150 0.050 0.244 0.228 0.050 0.016 DIM PINS D D D 8 14 16 MILLIMETERS MIN MAX 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 3.80 4.00 1.27 5.80 6.20 0.40 1.27 INCHES MILLIMETERS MIN MAX MIN MAX 0.189 0.197 4.80 5.00 0.337 0.344 8.55 8.75 0.386 0.394 9.80 10.00 21-0041A D E DIM E1 A A1 A2 A3 B B1 C D1 E E1 e eA eB L A3 A A2 L A1 0° - 15° C e B1 B eA eB D1 Plastic DIP PLASTIC DUAL-IN-LINE PACKAGE (0.300 in.) INCHES MAX MIN 0.200 – – 0.015 0.175 0.125 0.080 0.055 0.022 0.016 0.065 0.045 0.012 0.008 0.080 0.005 0.325 0.300 0.310 0.240 – 0.100 – 0.300 0.400 – 0.150 0.115 DIM PINS D D D D D D 8 14 16 18 20 24 INCHES MIN MAX 0.348 0.390 0.735 0.765 0.745 0.765 0.885 0.915 1.015 1.045 1.14 1.265 MILLIMETERS MIN MAX – 5.08 0.38 – 3.18 4.45 1.40 2.03 0.41 0.56 1.14 1.65 0.20 0.30 0.13 2.03 7.62 8.26 6.10 7.87 2.54 – 7.62 – – 10.16 2.92 3.81 MILLIMETERS MIN MAX 8.84 9.91 18.67 19.43 18.92 19.43 22.48 23.24 25.78 26.54 28.96 32.13 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 © 1994 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.