MAX1487EPA

19-0122; Rev 8; 10/03 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers General Description The MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 are low-power transceivers for RS-485 and RS422 communication. Each part contains one driver and one receiver. The MAX483, MAX487, MAX488, and MAX489 feature reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, thus allowing error-free data transmission up to 250kbps. The driver slew rates of the MAX481, MAX485, MAX490, MAX491, and MAX1487 are not limited, allowing them to transmit up to 2.5Mbps. These transceivers draw between 120µA and 500µA of supply current when unloaded or fully loaded with disabled drivers. Additionally, the MAX481, MAX483, and MAX487 have a low-current shutdown mode in which they consume only 0.1µA. All parts operate from a single 5V supply. 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 the input is open circuit. The MAX487 and MAX1487 feature quarter-unit-load receiver input impedance, allowing up to 128 MAX487/ MAX1487 transceivers on the bus. Full-duplex communications are obtained using the MAX488–MAX491, while the MAX481, MAX483, MAX485, MAX487, and MAX1487 are designed for half-duplex applications. __Next Generation Device Features ♦ For Fault-Tolerant Applications MAX3430: ±80V Fault-Protected, Fail-Safe, 1/4 Unit Load, +3.3V, RS-485 Transceiver MAX3440E–MAX3444E: ±15kV ESD-Protected, ±60V Fault-Protected, 10Mbps, Fail-Safe, RS-485/J1708 Transceivers ♦ For Space-Constrained Applications MAX3460–MAX3464: +5V, Fail-Safe, 20Mbps, Profibus RS-485/RS-422 Transceivers MAX3362: +3.3V, High-Speed, RS-485/RS-422 Transceiver in a SOT23 Package MAX3280E–MAX3284E: ±15kV ESD-Protected, 52Mbps, +3V to +5.5V, SOT23, RS-485/RS-422, True Fail-Safe Receivers MAX3293/MAX3294/MAX3295: 20Mbps, +3.3V, SOT23, RS-855/RS-422 Transmitters ♦ For Multiple Transceiver Applications MAX3030E–MAX3033E: ±15kV ESD-Protected, +3.3V, Quad RS-422 Transmitters ♦ For Fail-Safe Applications MAX3080–MAX3089: Fail-Safe, High-Speed (10Mbps), Slew-Rate-Limited RS-485/RS-422 Transceivers ♦ For Low-Voltage Applications MAX3483E/MAX3485E/MAX3486E/MAX3488E/ MAX3490E/MAX3491E: +3.3V Powered, ±15kV ESD-Protected, 12Mbps, Slew-Rate-Limited, True RS-485/RS-422 Transceivers Ordering Information appears at end of data sheet. MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 ________________________Applications Low-Power RS-485 Transceivers Low-Power RS-422 Transceivers Level Translators Transceivers for EMI-Sensitive Applications Industrial-Control Local Area Networks ______________________________________________________________Selection Table PART NUMBER MAX481 MAX483 MAX485 MAX487 MAX488 MAX489 MAX490 MAX491 MAX1487 HALF/FULL DUPLEX Half Half Half Half Full Full Full Full Half DATA RATE (Mbps) 2.5 0.25 2.5 0.25 0.25 0.25 2.5 2.5 2.5 SLEW-RATE LIMITED No Yes No Yes Yes Yes No No No LOW-POWER SHUTDOWN Yes Yes No Yes No No No No No RECEIVER/ DRIVER ENABLE Yes Yes Yes Yes No Yes No Yes Yes QUIESCENT CURRENT (µA) 300 120 300 120 120 120 300 300 230 NUMBER OF TRANSMITTERS ON BUS 32 32 32 128 32 32 32 32 128 PIN COUNT 8 8 8 8 8 14 8 14 8 ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC) .............................................................12V Control Input Voltage (RE, DE)...................-0.5V to (VCC + 0.5V) Driver Input Voltage (DI).............................-0.5V to (VCC + 0.5V) Driver Output Voltage (A, B)...................................-8V to +12.5V Receiver Input Voltage (A, B).................................-8V to +12.5V Receiver Output Voltage (RO).....................-0.5V to (VCC +0.5V) Continuous Power Dissipation (TA = +70°C) 8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ....727mW 14-Pin Plastic DIP (derate 10.00mW/°C above +70°C) ..800mW 8-Pin SO (derate 5.88mW/°C above +70°C).................471mW 14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW 8-Pin µMAX (derate 4.1mW/°C above +70°C) ..............830mW 8-Pin CERDIP (derate 8.00mW/°C above +70°C).........640mW 14-Pin CERDIP (derate 9.09mW/°C above +70°C).......727mW Operating Temperature Ranges MAX4_ _C_ _/MAX1487C_ A ...............................0°C to +70°C MAX4_ _E_ _/MAX1487E_ A .............................-40°C to +85°C MAX4_ _MJ_/MAX1487MJA ...........................-55°C to +125°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 = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2) PARAMETER Differential Driver Output (no load) Differential Driver Output (with load) Change in Magnitude of Driver Differential Output Voltage for Complementary Output States Driver Common-Mode Output Voltage Change in Magnitude of Driver Common-Mode Output Voltage for Complementary Output States Input High Voltage Input Low Voltage Input Current SYMBOL VOD1 VOD2 R = 50Ω (RS-422) R = 27Ω (RS-485), Figure 4 R = 27Ω or 50Ω, Figure 4 R = 27Ω or 50Ω, Figure 4 R = 27Ω or 50Ω, Figure 4 DE, DI, RE DE, DI, RE DE, DI, RE DE = 0V; VCC = 0V or 5.25V, all devices except MAX487/MAX1487 MAX487/MAX1487, DE = 0V, VCC = 0V or 5.25V Receiver Differential Threshold Voltage Receiver Input Hysteresis Receiver Output High Voltage Receiver Output Low Voltage Three-State (high impedance) Output Current at Receiver VTH ∆VTH VOH VOL IOZR -7V ≤ VCM ≤ 12V VCM = 0V IO = -4mA, VID = 200mV IO = 4mA, VID = -200mV 0.4V ≤ VO ≤ 2.4V -7V ≤ VCM ≤ 12V, all devices except MAX487/MAX1487 Receiver Input Resistance RIN -7V ≤ VCM ≤ 12V, MAX487/MAX1487 48 kΩ 12 3.5 0.4 ±1 VIN = 12V VIN = -7V VIN = 12V VIN = -7V -0.2 70 2.0 0.8 ±2 1.0 mA -0.8 0.25 -0.2 0.2 mA V mV V V µA kΩ 2 1.5 5 0.2 3 0.2 CONDITIONS MIN TYP MAX 5 UNITS V V ∆VOD VOC ∆VOD VIH VIL IIN1 V V V V V µA Input Current (A, B) IIN2 2 _______________________________________________________________________________________ Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers DC ELECTRICAL CHARACTERISTICS (continued) (VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS MAX488/MAX489, DE, DI, RE = 0V or VCC MAX490/MAX491, DE, DI, RE = 0V or VCC No-Load Supply Current (Note 3) ICC MAX481/MAX485, RE = 0V or VCC MAX1487, RE = 0V or VCC MAX483/MAX487, RE = 0V or VCC Supply Current in Shutdown Driver Short-Circuit Current, VO = High Driver Short-Circuit Current, VO = Low Receiver Short-Circuit Current ISHDN IOSD1 IOSD2 IOSR DE = VCC DE = 0V DE = VCC DE = 0V DE = 5V MAX483 MAX487 MIN TYP 120 300 500 300 300 230 350 250 120 0.1 35 35 7 MAX 250 500 900 500 500 400 650 400 250 10 250 250 95 µA UNITS MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 DE = 0V MAX481/483/487, DE = 0V, RE = VCC -7V ≤ VO ≤12V (Note 4) -7V ≤ VO ≤12V (Note 4) 0V ≤ VO ≤ VCC µA mA mA mA SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487 (VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2) PARAMETER Driver Input to Output Driver Output Skew to Output Driver Rise or Fall Time Driver Enable to Output High Driver Enable to Output Low Driver Disable Time from Low Driver Disable Time from High Receiver Input to Output SYMBOL CONDITIONS tPLH Figures 6 and 8, RDIFF = 54Ω, CL1 = CL2 = 100pF tPHL tSKEW Figures 6 and 8, RDIFF = 54Ω, CL1 = CL2 = 100pF MAX481, MAX485, MAX1487 Figures 6 and 8, RDIFF = 54Ω, tR, tF MAX490C/E, MAX491C/E CL1 = CL2 = 100pF MAX490M, MAX491M tZH Figures 7 and 9, CL = 100pF, S2 closed tZL Figures 7 and 9, CL = 100pF, S1 closed tLZ Figures 7 and 9, CL = 15pF, S1 closed tHZ Figures 7 and 9, CL = 15pF, S2 closed Figures 6 and 10, MAX481, MAX485, MAX1487 tPLH, tPHL RDIFF = 54Ω, MAX490C/E, MAX491C/E CL1 = CL2 = 100pF MAX490M, MAX491M tSKD tZL tZH tLZ tHZ fMAX tSHDN Figures 6 and 10, RDIFF = 54Ω, CL1 = CL2 = 100pF Figures 5 and 11, CRL = 15pF, S1 closed Figures 5 and 11, CRL = 15pF, S2 closed Figures 5 and 11, CRL = 15pF, S1 closed Figures 5 and 11, CRL = 15pF, S2 closed MAX481 (Note 5) 2.5 50 MIN 10 10 3 5 3 TYP 30 30 5 15 15 15 40 40 40 40 90 90 90 13 20 20 20 20 200 50 50 50 50 600 MAX 60 60 10 40 25 40 70 70 70 70 200 150 200 UNITS ns ns ns ns ns ns ns ns 20 20 20 | tPLH - tPHL | Differential Receiver Skew Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable Time from Low Receiver Disable Time from High Maximum Data Rate Time to Shutdown ns ns ns ns ns Mbps ns _______________________________________________________________________________________ 3 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487 (continued) (VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS Figures 7 and 9, CL = 100pF, S2 closed Figures 7 and 9, CL = 100pF, S1 closed Figures 5 and 11, CL = 15pF, S2 closed, A - B = 2V Figures 5 and 11, CL = 15pF, S1 closed, B - A = 2V MIN TYP 40 40 300 300 MAX 100 100 1000 1000 UNITS ns ns ns ns Driver Enable from Shutdown to tZH(SHDN) Output High (MAX481) Driver Enable from Shutdown to tZL(SHDN) Output Low (MAX481) Receiver Enable from Shutdown tZH(SHDN) to Output High (MAX481) Receiver Enable from Shutdown tZL(SHDN) to Output Low (MAX481) SWITCHING CHARACTERISTICS—MAX483, MAX487/MAX488/MAX489 (VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2) PARAMETER Driver Input to Output Driver Output Skew to Output Driver Rise or Fall Time Driver Enable to Output High Driver Enable to Output Low Driver Disable Time from Low Driver Disable Time from High Receiver Input to Output SYMBOL tPLH tPHL tSKEW tR, tF tZH tZL tLZ tHZ tPLH tPHL tSKD tZL tZH tLZ tHZ fMAX tSHDN tZH(SHDN) tZL(SHDN) tZH(SHDN) tZL(SHDN) CONDITIONS Figures 6 and 8, RDIFF = 54Ω, CL1 = CL2 = 100pF Figures 6 and 8, RDIFF = 54Ω, CL1 = CL2 = 100pF Figures 6 and 8, RDIFF = 54Ω, CL1 = CL2 = 100pF Figures 7 and 9, CL = 100pF, S2 closed Figures 7 and 9, CL = 100pF, S1 closed Figures 7 and 9, CL = 15pF, S1 closed Figures 7 and 9, CL = 15pF, S2 closed Figures 6 and 10, RDIFF = 54Ω, CL1 = CL2 = 100pF Figures 6 and 10, RDIFF = 54Ω, CL1 = CL2 = 100pF Figures 5 and 11, CRL = 15pF, S1 closed Figures 5 and 11, CRL = 15pF, S2 closed Figures 5 and 11, CRL = 15pF, S1 closed Figures 5 and 11, CRL = 15pF, S2 closed tPLH, tPHL < 50% of data period MAX483/MAX487 (Note 5) MAX483/MAX487, Figures 7 and 9, CL = 100pF, S2 closed MAX483/MAX487, Figures 7 and 9, CL = 100pF, S1 closed MAX483/MAX487, Figures 5 and 11, CL = 15pF, S2 closed MAX483/MAX487, Figures 5 and 11, CL = 15pF, S1 closed 250 50 200 600 2000 2000 2500 2500 250 250 250 300 300 250 250 100 20 20 20 20 50 50 50 50 MIN 250 250 TYP 800 800 100 MAX 2000 2000 800 2000 2000 2000 3000 3000 2000 2000 UNITS ns ns ns ns ns ns ns ns ns ns ns ns ns kbps ns ns ns ns ns I tPLH - tPHL I Differential Receiver Skew Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable Time from Low Receiver Disable Time from High Maximum Data Rate Time to Shutdown Driver Enable from Shutdown to Output High Driver Enable from Shutdown to Output Low Receiver Enable from Shutdown to Output High Receiver Enable from Shutdown to Output Low 4 _______________________________________________________________________________________ Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICS Note 1: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise specified. Note 2: All typical specifications are given for VCC = 5V and TA = +25°C. Note 3: Supply current specification is valid for loaded transmitters when DE = 0V. Note 4: Applies to peak current. See Typical Operating Characteristics. Note 5: The MAX481/MAX483/MAX487 are put into shutdown by bringing RE high and DE low. If the inputs are in this state for less than 50ns, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 600ns, the parts are guaranteed to have entered shutdown. See Low-Power Shutdown Mode section. MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 __________________________________________Typical Operating Characteristics (VCC = 5V, TA = +25°C, unless otherwise noted.) OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE MAX481-01 OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE MAX481-02 RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE 4.6 OUTPUT HIGH VOLTAGE (V) 4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 IRO = 8mA MAX481-03 45 40 OUTPUT CURRENT (mA) 35 30 25 20 15 10 5 0 0 0.5 1.0 1.5 2.0 -20 -18 OUTPUT CURRENT (mA) -16 -14 -12 -10 -8 -6 -4 -2 0 4.8 2.5 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 -50 -25 0 25 50 75 100 125 OUTPUT LOW VOLTAGE (V) OUTPUT HIGH VOLTAGE (V) TEMPERATURE (°C) RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE MAX481-04 DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE MAX481-05 DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE DIFFERENTIAL OUTPUT VOLTAGE (V) 2.3 2.2 2.1 2.0 1.9 1.8 1.7 1.6 1.5 -50 -25 0 25 50 75 100 125 R = 54Ω MAX481-06 0.9 0.8 OUTPUT LOW VOLTAGE (V) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -50 -25 0 25 50 75 100 IRO = 8mA 90 80 OUTPUT CURRENT (mA) 70 60 50 40 30 20 10 0 2.4 125 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 DIFFERENTIAL OUTPUT VOLTAGE (V) TEMPERATURE (°C) TEMPERATURE (°C) _______________________________________________________________________________________ 5 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 ____________________________Typical Operating Characteristics (continued) (VCC = 5V, TA = +25°C, unless otherwise noted.) OUTPUT CURRENT vs. DRIVER OUTPUT LOW VOLTAGE MAX481-07 OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGE MAX481-08 MAX481/MAX485/MAX490/MAX491 SUPPLY CURRENT vs. TEMPERATURE MAX481/MAX485; DE = VCC, RE = X MAX481-11 140 120 OUTPUT CURRENT (mA) 100 80 60 40 20 0 0 2 4 6 8 10 -120 -100 OUTPUT CURRENT (mA) -80 -60 -40 -20 0 600 500 SUPPLY CURRENT (µA) 400 300 200 100 MAX481; DE = 0, RE = VCC MAX485; DE = 0, RE = X, MAX481; DE = RE = 0 MAX490/MAX491; DE = RE = X 0 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 45 -50 -25 0 25 50 75 100 125 OUTPUT HIGH VOLTAGE (V) TEMPERATURE (°C) 12 OUTPUT LOW VOLTAGE (V) MAX483/MAX487–MAX489 SUPPLY CURRENT vs. TEMPERATURE MAX481-12 MAX1487 SUPPLY CURRENT vs. TEMPERATURE MAX481-13 600 500 SUPPLY CURRENT (µA) 400 300 MAX487; DE = VCC, RE = X MAX483; DE = VCC, RE = X 600 500 SUPPLY CURRENT (µA) 400 300 200 MAX1487; DE = 0V, RE = X MAX1487; DE = VCC, RE = X 200 100 MAX483/MAX487; DE = RE = 0, MAX488/MAX489; DE = RE = X 100 MAX483/MAX487; DE = 0, RE = VCC 0 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) 0 -60 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) 6 _______________________________________________________________________________________ Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers ______________________________________________________________Pin Description PIN MAX481/MAX483/ MAX485/MAX487/ MAX1487 DIP/SO 1 2 µMAX 3 4 MAX488/ MAX490 DIP/SO 2 — µMAX 4 — MAX489/ MAX491 DIP/SO 2 3 RO RE Receiver Output: If A > B by 200mV, RO will be high; If A < B by 200mV, RO will be low. Receiver Output Enable. RO is enabled when RE is low; RO is high impedance when RE is high. Driver Output Enable. The driver outputs, Y and Z, are enabled by bringing DE high. They are high impedance when DE is low. 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. 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. Ground Noninverting Driver Output Inverting Driver Output Noninverting Receiver Input and Noninverting Driver Output Noninverting Receiver Input Inverting Receiver Input and Inverting Driver Output Inverting Receiver Input Positive Supply: 4.75V ≤ VCC ≤ 5.25V No Connect—not internally connected NAME NAME FUNCTION FUNCTION MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 3 5 — — 4 DE 4 5 — — 6 — 7 — 8 — TOP VIEW 6 7 — — 8 — 1 — 2 — 3 4 5 6 — 8 — 7 1 — 5 6 7 8 — 2 — 1 3 — 5 6, 7 9 10 — 12 — 11 14 1, 8, 13 DI GND Y Z A A B B VCC N.C. RO 1 R 8 7 6 VCC B A GND RO 1 R 8 VCC 7B Rt 6 A 5 GND RE 2 DE 3 DI 4 D MAX481 MAX483 MAX485 MAX487 MAX1487 B Rt A R DE D DI 5 DIP/SO B VCC RO 1 2 3 8 A GND DI DE RE 2 DE 3 DI 4 D RO RE 4 MAX481 MAX483 MAX485 MAX487 MAX1487 µMAX 7 6 5 RE NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH. TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE. Figure 1. MAX481/MAX483/MAX485/MAX487/MAX1487 Pin Configuration and Typical Operating Circuit _______________________________________________________________________________________ 7 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 TOP VIEW VCC 1 RO 2 DI 3 GND 4 D R 8 7 6 5 A B Z Y DI 3 5Y VCC 1 VCC MAX488 MAX490 D Rt 6Z R RO DIP/SO 8A B A VCC RO 1 2 3 4 8 Z Y GND DI 4 GND NOTE: TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE. GND RO 2 R Rt 7 B D DI MAX488 MAX490 7 6 5 µMAX Figure 2. MAX488/MAX490 Pin Configuration and Typical Operating Circuit TOP VIEW DE 4 VCC 14 9 Y Rt 10 Z 12 A Rt 11 B VCC RE MAX489 MAX491 N.C. RO RE DE DI GND GND 1 2 3 4 5 6 7 D R 14 V CC 13 N.C. 12 A 11 B 10 Z 9 8 Y N.C. NC 1, 8, 13 3 RO 2 DI 5 D R RO R D DI DIP/SO 6, 7 RE GND GND DE Figure 3. MAX489/MAX491 Pin Configuration and Typical Operating Circuit __________Applications Information The MAX481/MAX483/MAX485/MAX487–MAX491 and MAX1487 are low-power transceivers for RS-485 and RS422 communications. The MAX481, MAX485, MAX490, MAX491, and MAX1487 can transmit and receive at data rates up to 2.5Mbps, while the MAX483, MAX487, MAX488, and MAX489 are specified for data rates up to 250kbps. The MAX488–MAX491 are full-duplex transceivers while the MAX481, MAX483, MAX485, MAX487, and MAX1487 are half-duplex. In addition, Driver Enable (DE) and Receiver Enable (RE) pins are included on the MAX481, MAX483, MAX485, MAX487, MAX489, MAX491, and MAX1487. When disabled, the driver and receiver outputs are high impedance. 8 MAX487/MAX1487: 128 Transceivers on the Bus The 48kΩ, 1/4-unit-load receiver input impedance of the MAX487 and MAX1487 allows up to 128 transceivers on a bus, compared to the 1-unit load (12k Ω input impedance) of standard RS-485 drivers (32 transceivers maximum). Any combination of MAX487/ MAX1487 and other RS-485 transceivers with a total of 32 unit loads or less can be put on the bus. The MAX481/MAX483/MAX485 and MAX488–MAX491 have standard 12kΩ Receiver Input impedance. _______________________________________________________________________________________ Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 _________________________________________________________________Test Circuits Y R VOD R Z VOC S2 TEST POINT RECEIVER OUTPUT CRL 15pF 1kΩ VCC S1 1kΩ Figure 4. Driver DC Test Load Figure 5. Receiver Timing Test Load 3V DE DI Y VID Z CL1 RDIFF A RO B RE OUTPUT UNDER TEST CL 500Ω S1 VCC S2 CL2 Figure 6. Driver/Receiver Timing Test Circuit Figure 7. Driver Timing Test Load MAX483/MAX487/MAX488/MAX489: Reduced EMI and Reflections The MAX483 and MAX487–MAX489 are slew-rate limited, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 12 shows the driver output waveform and its Fourier analysis of a 150kHz signal transmitted by a MAX481, MAX485, MAX490, MAX491, or MAX1487. High-frequency har- monics with large amplitudes are evident. Figure 13 shows the same information displayed for a MAX483, MAX487, MAX488, or MAX489 transmitting under the same conditions. Figure 13’s high-frequency harmonics have much lower amplitudes, and the potential for EMI is significantly reduced. _______________________________________________________________________________________ 9 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 _______________________________________________________Switching Waveforms 3V DI 0V 1.5V tPLH tPHL 1.5V 1/2 VO tZL(SHDN), tZL Y, Z VO Y 1/2 VO VO VDIFF 0V -VO 10% tR tSKEW = | tPLH - tPHL | VDIFF = V (Y) - V (Z) 90% 90% tF 10% VOL Y, Z 2.3V 0V tZH(SHDN), tZH tHZ 2.3V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH VOH -0.5V VOL +0.5V tLZ DE 0V 3V 1.5V 1.5V Z Figure 8. Driver Propagation Delays Figure 9. Driver Enable and Disable Times (except MAX488 and MAX490) 3V RE 0V RO VOH VOL VID -VID 0V 1.5V tPHL INPUT OUTPUT tPLH 0V RO 0V tZH(SHDN), tZH tHZ 1.5V 1.5V VCC RO tZL(SHDN), tZL tLZ VOL + 0.5V 1.5V 1.5V 1.5V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH A-B VOH - 0.5V Figure 10. Receiver Propagation Delays Figure 11. Receiver Enable and Disable Times (except MAX488 and MAX490) _________________Function Tables (MAX481/MAX483/MAX485/MAX487/MAX1487) Table 1. Transmitting INPUTS RE X X 0 1 DE 1 1 0 0 DI 1 0 X X Z 0 1 High-Z High-Z* OUTPUTS Y 1 0 High-Z High-Z* RE 0 0 0 1 Table 2. Receiving INPUTS DE 0 0 0 0 A-B > +0.2V < -0.2V Inputs open X OUTPUT RO 1 0 1 High-Z* X = Don't care High-Z = High impedance * Shutdown mode for MAX481/MAX483/MAX487 X = Don't care High-Z = High impedance * Shutdown mode for MAX481/MAX483/MAX487 10 ______________________________________________________________________________________ Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 10dB/div 10dB/div 0Hz 500kHz/div 5MHz 0Hz 500kHz/div 5MHz Figure 12. Driver Output Waveform and FFT Plot of MAX481/ MAX485/MAX490/MAX491/MAX1487 Transmitting a 150kHz Signal Figure 13. Driver Output Waveform and FFT Plot of MAX483/ MAX487–MAX489 Transmitting a 150kHz Signal Low-Power Shutdown Mode (MAX481/MAX483/MAX487) 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. In shutdown, the devices typically draw only 0.1µA of supply current. RE and DE may be driven simultaneously; the parts are guaranteed not to enter shutdown if RE is high and DE is low for less than 50ns. If the inputs are in this state for at least 600ns, the parts are guaranteed to enter shutdown. For the MAX481, MAX483, and MAX487, the tZH and tZL enable times assume the part was not in the lowpower shutdown state (the MAX485/MAX488–MAX491 and MAX1487 can not be shut down). The tZH(SHDN) and tZL(SHDN) enable times assume the parts were shut down (see Electrical Characteristics). It takes the drivers and receivers longer to become enabled from the low-power shutdown state (tZH(SHDN), tZL(SHDN)) than from the operating mode –– — (tZH, tZL). (The parts are in operating mode if the RE , DE inputs equal a logical 0,1 or 1,1 or 0, 0.) 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. Propagation Delay Many digital encoding schemes depend on the difference between the driver and receiver propagation delay times. Typical propagation delays are shown in Figures 15–18 using Figure 14’s test circuit. The difference in receiver delay times, | tPLH - tPHL |, is typically under 13ns for the MAX481, MAX485, MAX490, MAX491, and MAX1487 and is typically less than 100ns for the MAX483 and MAX487–MAX489. The driver skew times are typically 5ns (10ns max) for the MAX481, MAX485, MAX490, MAX491, and MAX1487, and are typically 100ns (800ns max) for the MAX483 and MAX487–MAX489. ______________________________________________________________________________________ 11 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 100pF Z TTL IN tR, tF < 6ns D Y R = 54Ω A B R RECEIVER OUT 100pF Figure 14. Receiver Propagation Delay Test Circuit A 500mV/div VCC = 5V TA = +25°C B 500mV/div VCC = 5V TA = +25°C B RO A 2V/div 2V/div RO 20ns/div 20ns/div Figure 15. MAX481/MAX485/MAX490/MAX491/MAX1487 Receiver tPHL Figure 16. MAX481/MAX485/MAX490/MAX491/MAX1487 Receiver tPLH A 500mV/div VCC = 5V TA = +25°C B 500mV/div VCC = 5V TA = +25°C B RO 2V/div A 2V/div RO 400ns/div 400ns/div Figure 17. MAX483, MAX487–MAX489 Receiver tPHL Figure 18. MAX483, MAX487–MAX489 Receiver tPLH 12 ______________________________________________________________________________________ Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 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 23. Figures 19 and 20 show the system differential voltage for the parts driving 4000 feet of 26AWG twisted-pair wire at 110kHz into 120Ω loads. 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 MAX483 and MAX487–MAX489 are more tolerant of imperfect termination. MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 Typical Applications The MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 transceivers are designed for bidirectional data communications on multipoint bus transmission lines. DI 5V 0V DI 5V 0V 1V VY-VZ 0V -1V VY-VZ 1V 0V -1V RO 5V 0V RO 5V 0V 2µs/div 2µs/div Figure 19. MAX481/MAX485/MAX490/MAX491/MAX1487 System Differential Voltage at 110kHz Driving 4000ft of Cable Figure 20. MAX483, MAX487–MAX489 System Differential Voltage at 110kHz Driving 4000ft of Cable 120Ω DI B 120Ω B DE D DE RO RE A B A B A A D DI R R RO RE R MAX481 MAX483 MAX485 MAX487 MAX1487 D D R DI DE RO RE DI DE RO RE Figure 21. MAX481/MAX483/MAX485/MAX487/MAX1487 Typical Half-Duplex RS-485 Network ______________________________________________________________________________________ 13 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 A RO RE DE Z DI Y 120Ω 120Ω Z DE B 120Ω 120Ω Y Z B A Y Z B A A RE RO R B D DI D Y R R D D R MAX489 MAX491 DE RE RO DI DE RE RO DI NOTE: RE AND DE ON MAX489/MAX491 ONLY. Figure 22. MAX488–MAX491 Full-Duplex RS-485 Network Isolated RS-485 MAX488–MAX491 A RO RE DE DI For isolated RS-485 applications, see the MAX253 and MAX1480 data sheets. R B 120Ω DATA IN Z D 120Ω Y DATA OUT NOTE: RE AND DE ON MAX489/MAX491 ONLY. Figure 23. Line Repeater for MAX488–MAX491 14 ______________________________________________________________________________________ Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 _______________Ordering Information PART MAX481CPA MAX481CSA MAX481CUA MAX481C/D MAX481EPA MAX481ESA MAX481MJA MAX483CPA MAX483CSA MAX483CUA MAX483C/D MAX483EPA MAX483ESA MAX483MJA MAX485CPA MAX485CSA MAX485CUA MAX485C/D MAX485EPA MAX485ESA MAX485MJA MAX487CPA MAX487CSA MAX487CUA MAX487C/D MAX487EPA MAX487ESA MAX487MJA MAX488CPA MAX488CSA MAX488CUA MAX488C/D MAX488EPA MAX488ESA MAX488MJA MAX489CPD MAX489CSD MAX489C/D MAX489EPD MAX489ESD MAX489MJD TEMP. RANGE 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C PIN-PACKAGE 8 Plastic DIP 8 SO 8 µMAX Dice* 8 Plastic DIP 8 SO 8 CERDIP 8 Plastic DIP 8 SO 8 µMAX Dice* 8 Plastic DIP 8 SO 8 CERDIP 8 Plastic DIP 8 SO 8 µMAX Dice* 8 Plastic DIP 8 SO 8 CERDIP 8 Plastic DIP 8 SO 8 µMAX Dice* 8 Plastic DIP 8 SO 8 CERDIP 8 Plastic DIP 8 SO 8 µMAX Dice* 8 Plastic DIP 8 SO 8 CERDIP 14 Plastic DIP 14 SO Dice* 14 Plastic DIP 14 SO 14 CERDIP __Ordering Information (continued) PART MAX490CPA MAX490CSA MAX490CUA MAX490C/D MAX490EPA MAX490ESA MAX490MJA MAX491CPD MAX491CSD MAX491C/D MAX491EPD MAX491ESD MAX491MJD MAX1487CPA MAX1487CSA MAX1487CUA MAX1487C/D MAX1487EPA MAX1487ESA MAX1487MJA TEMP. RANGE 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C PIN-PACKAGE 8 Plastic DIP 8 SO 8 µMAX Dice* 8 Plastic DIP 8 SO 8 CERDIP 14 Plastic DIP 14 SO Dice* 14 Plastic DIP 14 SO 14 CERDIP 8 Plastic DIP 8 SO 8 µMAX Dice* 8 Plastic DIP 8 SO 8 CERDIP * Contact factory for dice specifications. _________________Chip Topographies MAX481/MAX483/MAX485/MAX487/MAX1487 V CC RO RE DE DI GND 0.080" (2.032mm) A N.C. N.C. B 0.054" (1.372mm) ______________________________________________________________________________________ 15 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 _____________________________________________Chip Topographies (continued) MAX488/MAX490 V CC RO N .C. N .C. DI GND 0.080" (2.032mm) Y A B 0.054" Z (1.372mm) RO RE DE DI GND 0.080" (2.032mm) Y MAX489/MAX491 V CC A B Z 0.054" (1.372mm) TRANSISTOR COUNT: 248 SUBSTRATE CONNECTED TO GND 16 ______________________________________________________________________________________ Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) SOICN .EPS INCHES DIM A A1 B C e E H L MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050 MILLIMETERS MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 1.27 N E H VARIATIONS: 1 INCHES MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.00 N MS012 8 AA 14 AB 16 AC TOP VIEW DIM D D D MIN 0.189 0.337 0.386 MAX 0.197 0.344 0.394 D A e B A1 L C 0∞-8∞ FRONT VIEW SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, .150" SOIC APPROVAL DOCUMENT CONTROL NO. REV. 21-0041 B 1 1 ______________________________________________________________________________________ 17 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 8LUMAXD.EPS 8 4X S 8 INCHES DIM A A1 A2 b c D e E H MIN 0.002 0.030 MAX 0.043 0.006 0.037 MILLIMETERS MAX MIN 0.05 0.75 1.10 0.15 0.95 ÿ 0.50±0.1 0.6±0.1 E H 1 0.6±0.1 1 D L α S BOTTOM VIEW 0.014 0.010 0.007 0.005 0.120 0.116 0.0256 BSC 0.120 0.116 0.198 0.188 0.026 0.016 0∞ 6∞ 0.0207 BSC 0.25 0.36 0.13 0.18 2.95 3.05 0.65 BSC 2.95 3.05 4.78 5.03 0.41 0.66 0∞ 6∞ 0.5250 BSC TOP VIEW A2 A1 A e c b L α SIDE VIEW FRONT VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, 8L uMAX/uSOP APPROVAL DOCUMENT CONTROL NO. REV. 21-0036 J 1 1 18 ______________________________________________________________________________________ Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) PDIPN.EPS MAX481/MAX483/MAX485/MAX487–MAX491 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 ____________________ 19 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.