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Part: MAX491M
Category:
Communication
-> Transeivers
Description: -
Company: Maxim Integrated Products
Datasheet: Download MAX491M datasheet File size : 687 kB
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Datasheet text preview:
19-0122; Rev 7; 6/03
Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers
General Description
The MAX481, MAX483, MAX485, MAX487MAX491, 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. T h e 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 MAX488MAX491, while the MAX481, MAX483, MAX485, MAX487, and MAX1487 are designed for half-duplex applications.
____________________________Features
o In µMAX Package: Smallest 8-Pin SO o Slew-Rate Limited for Error-Free Data Transmission (MAX483/487/488/489) o 0.1µALow-Current Shutdown Mode (MAX481/483/487) o Low Quiescent Current: 120µA (MAX483/487/488/489) 230µA (MAX1487) 300µA (MAX481/485/490/491) o -7V to +12V Common-Mode Input Voltage Range o Three-State Outputs o 30ns Propagation Delays, 5ns Skew (MAX481/485/490/491/1487) o Full-Duplex and Half-Duplex Versions Available o Operate from a Single 5V Supply o Allows up to 128 Transceivers on the Bus (MAX487/MAX1487) o Current-Limiting and Thermal Shutdown for Driver Overload Protection
MAX481/MAX483/MAX485/MAX487MAX491/MAX1487
________________________Applications
Low-Power RS-485 Transceivers Low-Power RS-422 Transceivers Level Translators Transceivers for EMI-Sensitive Applications Industrial-Control Local Area Networks
PART MAX481CPA MAX481CSA MAX481CUA MAX481C/D
Ordering Information
TEMP RANGE 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C PIN-PACKAGE 8 Plastic DIP 8 SO 8 µMAX Dice*
Ordering Information continued at end of data sheet. *Contact factory for dice specifications.
______________________________________________________________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
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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/MAX487MAX491/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 VOD VOC VOD VIH VIL IIN1 R = 50 (RS-422) R = 27 (RS-485), Figure 4 R = 27 or 50, Figure 4 R = 27 or 50, Figure 4 R = 27 or 50, 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 k 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 k 2 1.5 5 0.2 3 0.2 CONDITIONS MIN TYP MAX 5 UNITS V V
V V V V V µA
Input Current (A, B)
IIN2
2
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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 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/MAX487MAX491/MAX1487
MAX487 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 = 54, CL1 = CL2 = 100pF tPHL tSKEW Figures 6 and 8, RDIFF = 54, CL1 = CL2 = 100pF MAX481, MAX485, MAX1487 Figures 6 and 8, RDIFF = 54, 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 MAX490C/E, MAX491C/E tPLH, tPHL RDIFF = 54, CL1 = CL2 = 100pF MAX490M, MAX491M tR, tF tSKD tZL tZH tLZ tHZ fMAX tSHDN Figures 6 and 10, RDIFF = 54, 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
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