1326555919 22364 ft52908 sumant khalateimplementing rs458 on avr
DESCRIPTION
GeneralTRANSCRIPT
Contents
I Content 2
1 Introduction 31.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.4 Handshaking . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.5 Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.6 Pin labeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.7 RS485 in Real World . . . . . . . . . . . . . . . . . . . . . . . 61.8 Waveform example . . . . . . . . . . . . . . . . . . . . . . . . 61.9 Differences between RS232 and RS485 . . . . . . . . . . . . . 7
2 Characteristics of RS485 8
3 MAX485 IC 9
4 Hardware 114.1 Single Master and Slave . . . . . . . . . . . . . . . . . . . . . 114.2 Multi Master and Slave . . . . . . . . . . . . . . . . . . . . . . 13
II Datasheet 15MAX485 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
I
List of Figures
1.1 Waveform of 0xD3 transmitted on RS485 . . . . . . . . . . . 7
3.1 Pinout diagram of MAX485 and its connection . . . . . . . . 10
4.1 Simple RS485 Communication . . . . . . . . . . . . . . . . . . 124.2 Multi Master-Slave RS485 Communication . . . . . . . . . . . 13
1
Part I
Content
2
Chapter 1
Introduction
RS485 is the physical layer for many higher-level protocols, includingModbus1, Profibus2 and other Fieldbus3 systems, SCSI-2, SCSI-3, and BitBus. Unlike RS232, which has a transmit wire and a receive wire, RS485has a transmit wire pair. Typically one wire is labelled A and the other islabelled B, and the wires are twisted together (twisted pair). This allowsRS485 to transmit over much longer distances, using equivalent wires andequivalent transmitters and receivers, than RS232. Many RS485 implemen-tations use 2 wires (1 pair). At all times, at most one device is transmitting onthe pair, and all the other devices on the network are listening (half-duplex).It is the responsibility of user software to ensure that several different devicesdon’t try to transmit at the same time, this can be a tricky coordination task.
1.1 Overview
RS485 only specifies electrical characteristics of the driver and the receiver.It does not specify or recommend any communications protocol. RS485 en-ables the configuration of inexpensive local networks and multi-drop com-munications links. It offers data transmission speeds of 35 Mbit/s up to 10m and 100 kbit/s at 1200 m. Since it uses a differential balanced line overtwisted pair (like RS422), it can span relatively large distances (up to 4,000feet (1,200 m)). A rule of thumb is that the speed in bit/s multiplied by thelength in meters should not exceed 108. Thus a 50 meter cable should notsignal faster than 2 Mbit/s.
1It is a protocol developed by Modicom.2It is another protocol developed by BMBF (German department of education and research)3Protocol developed by
3
1.2. REQUIREMENTS
The recommended arrangement of the wires is as a connected seriesof point-to-point (multi-dropped) nodes, a line or bus, not a star, ring, ormultiply connected network. Ideally, the two ends of the cable will have atermination resistor connected across the two wires. Without terminationresistors, reflections of fast driver edges can cause multiple data edges thatcan cause data corruption. Termination resistors also reduce electrical noisesensitivity due to the lower impedance, and bias resistors are required. Thevalue of each termination resistor should be equal to the cable impedance(typically, 100 ohms for twisted pairs).
1.2 Requirements
A full-duplex RS485 system requires 3 twisted pairs, 2 twisted pairs for sig-nalling, and another conductor for ground. This so-called four-wire RS485system requires 5 wires. A half-duplex system only requires 2 twisted pairsone twisted pair for signalling, and another conductor for ground. This so-called two-wire RS485 system requires 3 wires.
The ground conductor can be eliminated in some cases, but it is safe tostick to Three wire system.
1.3 Limitations
Standard RS485 is limited to a maximum speed of 35 Mbps with a networklength of 12 meters, and 100 Kbps with a network length of 1200 meters.With interface devices that exceed standards and careful network design,higher throughput over longer cables is possible.
With the use of Shielded twisted pair(STP) or Foiled twisted pair(FTP)cable the throughput can be increased even more.
1.4 Handshaking
There is no hardware handshaking in RS485. If handshaking is requiredfor RS485 it can be done using X-On / X-Off handshaking protocol. TheRS485 standard originally used half-duplex communication and handshakingsignals such as RTS / CTS to control the direction of data flow. Many USBto serial converters come with ADDC (Automatic Data Direction Control)to automatically sense and control data direction, making the handshakingsignal method obsolete.
4
1.5. TERMINATION
1.5 Termination
Perhaps the most controversial part of RS485 is what to do at the end ofthe line. There are a wide variety of popular techniques, each of which worksgreat under one narrow range of conditions.
• Unterminated: This is the simplest system, but only works if boththe data rate and length are low enough. A good guideline for when itcan be used is to keep the product of the data rate (in baud) and thelongest end-to-end cable length below four hundred thousand. Numberof transmitters / receivers aren’t important (just keep them withinRS485 specification). This is the only case where a star bus topologyworks reliably.
• One-way resistor termination: Only works if there is only onetransmitter, which must be at the opposite end (from the resistor)of a linear bus.
• Two-way resistor termination: Only works with a linear bus, butallows transmitters only at the endpoints of the bus.
• AC termination: While AC termination may work well on back-planes, others discourage its use on RS485 lines: ”In practice, I havenever seen it”
1.6 Pin labeling
The EIA-485 differential line consists of two pins:
• A aka – aka TxD–/RxD– aka inverting pin
• B aka + aka TxD+/RxD+ aka non-inverting pin
• SC aka G aka reference pin
The SC line is the optional voltage reference connection. This is thereference potential used by the transceiver to measure the A and B voltages.The B line is positive (compared to A) when the line is idle (i.e, data is 1).In addition to the A and B connections, the EIA standard also specifies athird interconnection point called C, which is the common signal referenceground. These names are all in use on various equipment, but the actualstandard released by EIA only uses the names A and B.
5
1.7. RS485 IN REAL WORLD
However, despite the unambiguous standard, there is much confusionabout which is which, The EIA-485 signaling specification states that signalA is the inverting or ′−′ pin and signal B is the non− inverting or ′+′ pin.This is in conflict with the A/B naming used by a number of differentialtransceiver manufacturers, including, among others.
• Texas Instruments, as seen in their application handbook on EIA-422/485 communications (A=non-inverting, B=inverting).
• Intersil, as seen in their data sheet for the ISL4489 transceiver.
• Maxim, as seen in their data sheet for the MAX485 transceiver
These manufacturers are incorrect, but their practice is in widespreaduse. Therefore, care must be taken when using A/B naming.
1.7 RS485 in Real World
Now being used commonly in the pro audio industry to control digital audioand signal processors such as the DBX driverack and other manufacturersequivalent products. Preferred to RS232 due to cheaper cabling run costsand the common availability of cables (similar to RJ-45 ). When wiring aRS485 network, always connect A to A, B to B, and G to G
Many people recommend writing prototype software as if it will be con-nected to a half-duplex RS485 network. Then the software will work un-changed when connected to a full-duplex RS485 network, a RS232 network,and a variety of other communication media.
Many people recommend wiring things up on a prototype with Category-5cable connected as point-to-point full-duplex RS485. The CAT-5 cable allowsyou to relatively quickly switch to half-duplex RS485, or the 3 wires of RS232,or a variety of other communication protocols without pulling any new cables.The point-to-point full-duplex RS485 network allows you to get the completeprototype system fully operational quickly, since it is easier to debug andmore immune to certain common problems on other systems (noise problemson RS232, turn-around problems on half-duplex RS485, etc.).
1.8 Waveform example
The image below shows potentials of the ′+′ and ′−′ pins of an EIA-485line during transmission of one byte (0xD3, least significant bit first) of datausing an asynchronous start-stop method.
6
1.9. DIFFERENCES BETWEEN RS232 AND RS485
Figure 1.1: Waveform of 0xD3 transmitted on RS485
1.9 Differences between RS232 and RS485
• RS232 signal levels are typically -12 V to +12 V relative to the signalground.
• RS485 signal levels are typically 0 to +5 V relative to the signal ground.
• RS232 uses point-to-point unidirectional signal wires: There are onlytwo devices connected to a RS232 cable. The TxD output of a firstdevice connected to the RxD input of a second device, and the TxDoutput of the second device connected to the RxD input of the firstdevice. In a RS232 cable, data always flows in only one direction onany particular wire, from TxD to RxD.
• RS485 typically uses a linear network with bidirectional signal wires:There are typically many devices along a RS485 shared cable. TheA output of each device is connected to the A output of every otherdevice. In a RS485 cable, data typically flows in both directions alongany particular wire, sometimes from the A of the first device to theA of the second device, and at a later time from the A of the seconddevice to the A of the first device.
7
Chapter 2
Characteristics of RS485
Description RS485
Mode DifferentialMax number of drivers 32
Max number of receivers 32Mode of operation Full Duplex or Half DuplexNetwork topology Multi-Drop
Max distance (acc. standard) 1200m (4000ft)Max speed at 12 m 35 Mbs
Max speed at 1200 m 100 kbsReceiver input resistance ≥ 12ΩDriver load impedance 54Ω
Receiver input sensitivity ± 200mVReceiver input range -7...12V
Max driver output voltage -7...12VMin driver output voltage (with load) 1.5V
8
Chapter 3
MAX485 IC
The MAX485 IC are low-power transceivers for RS-485 and RS- 422communication. Each part contains one driver and one receiver. The driverslew rates of the IC are not limited, allowing them to transmit up to 2.5Mbps.
These transceiver draw between 120µA and 500µA of supply current whenunloaded or fully loaded with disabled drivers. Drivers are short circuitedprotected against excessive power dissipation by thermal shut-down circuitrythat places the driver output into High-impedance state. The receiver inputhas a fail-safe feature that guarantees a logic-high output if the input is opencircuit.
The serial data on DI pin is transmitted on the bus and the data on busis received on RO pin. The direction of data on bus is controlled by RE andDE pins, these pins are connected together and eventually connected to thecontrol device.
• When RE and DE is low, data on the bus is received on RO.
• When they are high the data on DI, is transmitted on bus.
9
MAX 485
MAX 485
Figure 3.1: Pinout diagram of MAX485 and its connection
10
Chapter 4
Hardware
To build the hardware you will require the following things.
1. ATmega32 (AVR Family Micro-controller)
2. MAX-485
3. Twisted Pair Cable
4.1 Single Master and Slave
First we will build a simple hardware with one master and one slave,following are the instructions to building the hardware.
• First connect the RO pin of MAX485 to RxD pin of ATmega32, thenfollowed by DI pin to TxD pin.
• Connect the RE & DE pins of MAX485 to anyone i/o pin of ATmega32.
• Build the same hardware, as stated above and connect it to other side(i.e slave) side.
11
4.1. SINGLE MASTER AND SLAVE
The following schematic shows you how to build thehardware1
100E 100E
Figure 4.1: Simple RS485 Communication
1The RO and DI pins MAX-485 pins are TTL compatible and not RS232
12
4.2. MULTI MASTER AND SLAVE
4.2 Multi Master and Slave
After you have done with simple point-to-point system, you can try com-plex systems with multi master and slave. In this section I have providedan example for two master and two slaves.
.
.
.
.
1 2
_1 _2
100E 100E
Figure 4.2: Multi Master-Slave RS485 Communication
13
Reference
• Wikipedia
Powred by: LATEX 2εAuthor: Khalate Sumant
14
Part II
Datasheet
15
MAX 485
16
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.
General DescriptionThe MAX481, MAX483, MAX485, MAX487–MAX491, andMAX1487 are low-power transceivers for RS-485 and RS-422 communication. Each part contains one driver and onereceiver. The MAX483, MAX487, MAX488, and MAX489feature reduced slew-rate drivers that minimize EMI andreduce 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 totransmit up to 2.5Mbps.These transceivers draw between 120µA and 500µA ofsupply current when unloaded or fully loaded with disableddrivers. Additionally, the MAX481, MAX483, and MAX487have a low-current shutdown mode in which they consumeonly 0.1µA. All parts operate from a single 5V supply.Drivers are short-circuit current limited and are protectedagainst excessive power dissipation by thermal shutdowncircuitry that places the driver outputs into a high-imped-ance state. The receiver input has a fail-safe feature thatguarantees a logic-high output if the input is open circuit.The MAX487 and MAX1487 feature quarter-unit-loadreceiver input impedance, allowing up to 128 MAX487/MAX1487 transceivers on the bus. Full-duplex communi-cations are obtained using the MAX488–MAX491, whilethe MAX481, MAX483, MAX485, MAX487, and MAX1487are designed for half-duplex applications.
________________________ApplicationsLow-Power RS-485 Transceivers
Low-Power RS-422 Transceivers
Level Translators
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
____________________________Features In µMAX Package: Smallest 8-Pin SO
Slew-Rate Limited for Error-Free DataTransmission (MAX483/487/488/489)
0.1µALow-Current Shutdown Mode(MAX481/483/487)
Low Quiescent Current:120µA (MAX483/487/488/489)230µA (MAX1487)300µA (MAX481/485/490/491)
-7V to +12V Common-Mode Input Voltage Range
Three-State Outputs
30ns Propagation Delays, 5ns Skew (MAX481/485/490/491/1487)
Full-Duplex and Half-Duplex Versions Available
Operate from a Single 5V Supply
Allows up to 128 Transceivers on the Bus(MAX487/MAX1487)
Current-Limiting and Thermal Shutdown forDriver Overload Protection
Ordering Information
Ordering Information continued at end of data sheet.*Contact factory for dice specifications.
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
________________________________________________________________ Maxim Integrated Products 1
______________________________________________________________Selection Table
19-0122; Rev 7; 6/03
PART TEMP RANGE PIN-PACKAGE
MAX481CPA 0°C to +70°C 8 Plastic DIP
MAX481CSA 0°C to +70°C 8 SO
MAX481CUA 0°C to +70°C 8 µMAXMAX481C/D 0°C to +70°C Dice*
MAX481
MAX483
MAX485
MAX487
MAX488
MAX489
MAX490
MAX491
MAX1487
PARTNUMBER
HALF/FULLDUPLEX
DATA RATE(Mbps)
SLEW-RATELIMITED
LOW-POWERSHUTDOWN
RECEIVER/DRIVERENABLE
QUIESCENTCURRENT
(µA)
NUMBER OFTRANSMITTERS
ON BUS
PINCOUNT
Half
Half
Half
Half
Full
Full
Full
Full
Half
2.5
0.25
2.5
0.25
0.25
0.25
2.5
2.5
2.5
No
Yes
No
Yes
Yes
Yes
No
No
No
Yes
Yes
No
Yes
No
No
No
No
No
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Yes
300
120
300
120
120
120
300
300
230
32
32
32
128
32
32
32
32
128
8
8
8
8
8
14
8
14
8
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGSSupply Voltage (VCC).............................................................12VControl 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 +12.5VReceiver Input Voltage (A, B).................................-8V to +12.5VReceiver 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) ....727mW14-Pin Plastic DIP (derate 10.00mW/°C above +70°C) ..800mW8-Pin SO (derate 5.88mW/°C above +70°C).................471mW
14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW8-Pin µMAX (derate 4.1mW/°C above +70°C) ..............830mW8-Pin CERDIP (derate 8.00mW/°C above +70°C).........640mW14-Pin CERDIP (derate 9.09mW/°C above +70°C).......727mW
Operating Temperature RangesMAX4_ _C_ _/MAX1487C_ A ...............................0°C to +70°CMAX4_ _E_ _/MAX1487E_ A.............................-40°C to +85°CMAX4_ _MJ_/MAX1487MJA ...........................-55°C to +125°C
Storage Temperature Range .............................-65°C to +160°CLead Temperature (soldering, 10sec) .............................+300°C
DC ELECTRICAL CHARACTERISTICS(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.
V
VIN = -7V
VIN = 12V
VIN = -7V
VIN = 12V
Input Current(A, B)
IIN2
VTH
kΩ48-7V ≤ VCM ≤ 12V, MAX487/MAX1487
RINReceiver Input Resistance
-7V ≤ VCM ≤ 12V, all devices exceptMAX487/MAX1487
R = 27Ω (RS-485), Figure 4
0.4V ≤ VO ≤ 2.4V
R = 50Ω (RS-422)
IO = 4mA, VID = -200mV
IO = -4mA, VID = 200mV
VCM = 0V
-7V ≤ VCM ≤ 12V
DE, DI, RE
DE, DI, RE
MAX487/MAX1487, DE = 0V, VCC = 0V or 5.25V
DE, DI, RE
R = 27Ω or 50Ω, Figure 4
R = 27Ω or 50Ω, Figure 4
R = 27Ω or 50Ω, Figure 4
DE = 0V;VCC = 0V or 5.25V,all devices exceptMAX487/MAX1487
CONDITIONS
kΩ12
µA±1IOZRThree-State (high impedance)Output Current at Receiver
V
0.4VOLReceiver Output Low Voltage
3.5VOHReceiver Output High Voltage
mV70∆VTHReceiver Input Hysteresis
V-0.2 0.2Receiver Differential ThresholdVoltage
-0.2mA
0.25
mA-0.8
1.0
1.5 5VOD2
Differential Driver Output(with load)
V2
V5VOD1Differential Driver Output (no load)
µA±2IIN1Input Current
V0.8VILInput Low Voltage
V2.0VIHInput High Voltage
V0.2∆VOD
Change in Magnitude of DriverCommon-Mode Output Voltagefor Complementary Output States
V0.2∆VOD
Change in Magnitude of DriverDifferential Output Voltage forComplementary Output States
V3VOCDriver Common-Mode OutputVoltage
UNITSMIN TYP MAXSYMBOLPARAMETER
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
_______________________________________________________________________________________ 3
SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
DC ELECTRICAL CHARACTERISTICS (continued)(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
mA7 950V ≤ VO ≤ VCCIOSRReceiver Short-Circuit Current
mA35 250-7V ≤ VO ≤12V (Note 4)IOSD2Driver Short-Circuit Current,VO = Low
mA35 250-7V ≤ VO ≤12V (Note 4)IOSD1Driver Short-Circuit Current,VO = High
MAX1487,RE = 0V or VCC
250 400
350 650
ns
10 30 60tPHL
Driver Rise or Fall Time
Figures 6 and 8, RDIFF = 54Ω, CL1 = CL2 = 100pF
ns
MAX490M, MAX491MMAX490C/E, MAX491C/E 20 90 150MAX481, MAX485, MAX1487
MAX490M, MAX491MMAX490C/E, MAX491C/EMAX481, MAX485, MAX1487
Figures 6 and 8, RDIFF = 54Ω,CL1 = CL2 = 100pF
MAX481 (Note 5)
Figures 5 and 11, CRL = 15pF, S2 closedFigures 5 and 11, CRL = 15pF, S1 closedFigures 5 and 11, CRL = 15pF, S2 closedFigures 5 and 11, CRL = 15pF, S1 closed
Figures 6 and 10, RDIFF = 54Ω,CL1 = CL2 = 100pF
Figures 6 and 8,RDIFF = 54Ω,CL1 = CL2 = 100pF
Figures 6 and 10,RDIFF = 54Ω,CL1 = CL2 = 100pF
CONDITIONS
ns
5 10tSKEW
ns50 200 600tSHDNTime to ShutdownMbps2.5fMAXMaximum Data Rate
ns20 50tHZReceiver Disable Time from Highns
10 30 60tPLH
20 50tLZReceiver Disable Time from Lowns20 50tZH
Driver Input to Output
Receiver Enable to Output Highns20 50tZLReceiver Enable to Output Low
20 90 200
ns
ns
13
40 70tHZ
tSKD
Driver Disable Time from High
| tPLH - tPHL | DifferentialReceiver Skew
ns40 70tLZDriver Disable Time from Low
ns40 70tZLDriver Enable to Output Low
3 15 40
ns
5 15 25 ns3 15 40
tR, tF
20 90 200
Driver Output Skew to Output
tPLH, tPHLReceiver Input to Output
40 70tZHDriver Enable to Output High
UNITSMIN TYP MAXSYMBOLPARAMETER
CONDITIONS UNITSMIN TYP MAXSYMBOLPARAMETER
230 400
300 500
MAX481/MAX485,RE = 0V or VCC
500 900
MAX490/MAX491,DE, DI, RE = 0V or VCC
300 500
MAX488/MAX489,DE, DI, RE = 0V or VCC
120 250
DE = VCC
300 500DE = 0V
DE = VCC
DE = 0V
µAMAX481/483/487, DE = 0V, RE = VCC 0.1 10ISHDNSupply Current in Shutdown 120 250
ICCNo-Load Supply Current(Note 3)
DE = 5V
DE = 0V
MAX483
MAX487MAX483/MAX487,RE = 0V or VCC
Figures 7 and 9, CL = 100pF, S2 closedFigures 7 and 9, CL = 100pF, S1 closedFigures 7 and 9, CL = 15pF, S1 closedFigures 7 and 9, CL = 15pF, S2 closed
µA
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
4 _______________________________________________________________________________________
SWITCHING CHARACTERISTICS—MAX483, MAX487/MAX488/MAX489(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487 (continued)(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
300 1000
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
CONDITIONS
ns40 100tZH(SHDN)Driver Enable from Shutdown toOutput High (MAX481)
nsFigures 5 and 11, CL = 15pF, S1 closed,B - A = 2V
tZL(SHDN)Receiver Enable from Shutdownto Output Low (MAX481)
ns40 100tZL(SHDN)Driver Enable from Shutdown toOutput Low (MAX481)
ns300 1000tZH(SHDN)Receiver Enable from Shutdownto Output High (MAX481)
UNITSMIN TYP MAXSYMBOLPARAMETER
tPLH
tSKEWFigures 6 and 8, RDIFF = 54Ω,CL1 = CL2 = 100pF
tPHL
Figures 6 and 8, RDIFF = 54Ω,CL1 = CL2 = 100pF
Driver Input to Output
Driver Output Skew to Output ns100 800
ns
ns2000MAX483/MAX487, Figures 7 and 9,CL = 100pF, S2 closed
tZH(SHDN)Driver Enable from Shutdown toOutput High
250 2000
ns2500MAX483/MAX487, Figures 5 and 11,CL = 15pF, S1 closed
tZL(SHDN)Receiver Enable from Shutdownto Output Low
ns2500MAX483/MAX487, Figures 5 and 11,CL = 15pF, S2 closed
tZH(SHDN)Receiver Enable from Shutdownto Output High
ns2000MAX483/MAX487, Figures 7 and 9,CL = 100pF, S1 closed
tZL(SHDN)Driver Enable from Shutdown toOutput Low
ns50 200 600MAX483/MAX487 (Note 5) tSHDNTime to Shutdown
tPHL
tPLH, tPHL < 50% of data period
Figures 5 and 11, CRL = 15pF, S2 closed
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 7 and 9, CL = 15pF, S2 closed
Figures 6 and 10, RDIFF = 54Ω,CL1 = CL2 = 100pF
Figures 7 and 9, CL = 15pF, S1 closed
Figures 7 and 9, CL = 100pF, S1 closed
Figures 7 and 9, CL = 100pF, S2 closed
CONDITIONS
kbps250fMAX
250 800 2000
Maximum Data Rate
ns20 50tHZReceiver Disable Time from High
ns
250 800 2000
20 50tLZReceiver Disable Time from Low
ns20 50tZHReceiver Enable to Output High
ns20 50tZLReceiver Enable to Output Low
ns
ns
100
300 3000tHZ
tSKD
Driver Disable Time from High
I tPLH - tPHL I DifferentialReceiver Skew
Figures 6 and 10, RDIFF = 54Ω,CL1 = CL2 = 100pF
ns300 3000tLZDriver Disable Time from Low
ns250 2000tZLDriver Enable to Output Low
ns
Figures 6 and 8, RDIFF = 54Ω,CL1 = CL2 = 100pF
ns250 2000tR, tF
250 2000
Driver Rise or Fall Time
ns
tPLHReceiver Input to Output
250 2000tZHDriver Enable to Output High
UNITSMIN TYP MAXSYMBOLPARAMETER
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
_______________________________________________________________________________________ 5
30
00 2.5
OUTPUT CURRENT vs.RECEIVER OUTPUT LOW VOLTAGE
5
25
MAX
481-
01
OUTPUT LOW VOLTAGE (V)
OUTP
UT C
URRE
NT (m
A)
1.5
15
10
0.5 1.0 2.0
20
35
40
45
0.9
0.1
-50 -25 25 75
RECEIVER OUTPUT LOW VOLTAGE vs.TEMPERATURE
0.3
0.7
TEMPERATURE (°C)
OUTP
UT L
OW V
OLTA
GE (V
)
0 50
0.5
0.8
0.2
0.6
0.4
0100 125
MAX
481-
04
IRO = 8mA
-20
-4
1.5 2.0 3.0 5.0
OUTPUT CURRENT vs.RECEIVER OUTPUT HIGH VOLTAGE
-8
-16
MAX
481-
02
OUTPUT HIGH VOLTAGE (V)
OUTP
UT C
URRE
NT (m
A)
2.5 4.0
-12
-18
-6
-14
-10
-2
03.5 4.5
4.8
3.2
-50 -25 25 75
RECEIVER OUTPUT HIGH VOLTAGE vs.TEMPERATURE
3.6
4.4
TEMPERATURE (°C)
OUTP
UT H
IGH
VOLT
AGE
(V)
0 50
4.0
4.6
3.4
4.2
3.8
3.0100 125
MAX
481-
03
IRO = 8mA
90
00 1.0 3.0 4.5
DRIVER OUTPUT CURRENT vs.DIFFERENTIAL OUTPUT VOLTAGE
10
70
MAX
481-
05
DIFFERENTIAL OUTPUT VOLTAGE (V)
OUTP
UT C
URRE
NT (m
A)
2.0 4.0
50
30
80
60
40
20
0.5 1.5 2.5 3.5
2.3
1.5-50 -25 25 125
DRIVER DIFFERENTIAL OUTPUT VOLTAGEvs. TEMPERATURE
1.7
2.1
MAX
481-
06
TEMPERATURE (°C)
DIFF
EREN
TIAL
OUT
PUT
VOLT
AGE
(V)
0 75
1.9
2.2
1.6
2.0
1.8
10050
2.4
R = 54Ω
__________________________________________Typical Operating Characteristics(VCC = 5V, TA = +25°C, unless otherwise noted.)
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 areguaranteed to have entered shutdown. See Low-Power Shutdown Mode section.
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
6 _______________________________________________________________________________________
____________________________Typical Operating Characteristics (continued)(VCC = 5V, TA = +25°C, unless otherwise noted.)
120
00 8
OUTPUT CURRENT vs.DRIVER OUTPUT LOW VOLTAGE
20
100
MAX
481-
07
OUTPUT LOW VOLTAGE (V)
OUTP
UT C
URRE
NT (m
A)
6
60
40
2 4
80
10 12
140 -120
0-7 -5 -1 5
OUTPUT CURRENT vs.DRIVER OUTPUT HIGH VOLTAGE
-20
-80
MAX
481-
08
OUTPUT HIGH VOLTAGE (V)
OUTP
UT C
URRE
NT (m
A)
-3 1
-60
3-6 -4 -2 0 2 4
-100
-40
100
-40-60 -20 40 100 120
MAX1487SUPPLY CURRENT vs. TEMPERATURE
300M
AX48
1-13
TEMPERATURE (°C)
SUPP
LY C
URRE
NT (µ
A)
20 60 80
500
200
600
400
00 140
MAX1487; DE = VCC, RE = X
MAX1487; DE = 0V, RE = X
100
-50 -25 50 100
MAX481/MAX485/MAX490/MAX491SUPPLY CURRENT vs. TEMPERATURE
300
MAX
481-
11
TEMPERATURE (°C)
SUPP
LY C
URRE
NT (µ
A)
25 75
500
200
600
400
00 125
MAX481/MAX485; DE = VCC, RE = X
MAX485; DE = 0, RE = X,MAX481; DE = RE = 0MAX490/MAX491; DE = RE = X
MAX481; DE = 0, RE = VCC
100
-50 -25 50 100
MAX483/MAX487–MAX489SUPPLY CURRENT vs. TEMPERATURE
300
MAX
481-
12
TEMPERATURE (°C)
SUPP
LY C
URRE
NT (µ
A)
25 75
500
200
600
400
00 125
MAX483; DE = VCC, RE = X
MAX487; DE = VCC, RE = X
MAX483/MAX487; DE = 0, RE = VCC
MAX483/MAX487; DE = RE = 0,MAX488/MAX489; DE = RE = X
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
_______________________________________________________________________________________ 7
______________________________________________________________Pin Description
MAX481MAX483MAX485MAX487MAX1487
TOP VIEW
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.
1
2
3
4
8
5
VCC
GND DI
DE
RE
RO R
D
RtRt7
6
D
R
DE
RE
DI
ROA
B
1
2
3
4
8
7
6
5
VCC
B
A
GND DI
DE
RE
RO
DIP/SO
R
D
1
2
3
4
8
7
6
5
VCC
A
GND
DERE
B
RO
µMAX
B
A
DI
MAX481MAX483MAX485MAX487MAX1487
Figure 1. MAX481/MAX483/MAX485/MAX487/MAX1487 Pin Configuration and Typical Operating Circuit
µMAX
—
—
5
6
7
8
—
2
—
1
3
—
µMAX
4
5
6
7
—
—
8
—
1
—
2
—
DIP/SO DIP/SO
2 3Receiver Output Enable. RO is enabled when RE is low; RO ishigh impedance when RE is high.
3 4
Driver Output Enable. The driver outputs, Y and Z, are enabledby bringing DE high. They are high impedance when DE is low. Ifthe driver outputs are enabled, the parts function as line drivers.While they are high impedance, they function as line receivers ifRE is low.
DIP/SO
—
4 5Driver 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 6, 7 Ground
— 9 Noninverting Driver Output
— 10 Inverting Driver Output
—
3
4
6 — Noninverting Receiver Input and Noninverting Driver Output
— 12 Noninverting Receiver Input
5
6
—
8
RE
DE
DI
GND
Y
Z
A
A
7 — — B Inverting Receiver Input and Inverting Driver Output
— 7 11 B Inverting Receiver Input
8 1 14 VCC Positive Supply: 4.75V ≤ VCC ≤ 5.25V
— — 1, 8, 13 N.C. No Connect—not internally connected
FUNCTIONNAME
431 2Receiver Output: If A > B by 200mV, RO will be high;If A < B by 200mV, RO will be low.
2 RO
PIN
FUNCTIONNAMEMAX481/MAX483/MAX485/MAX487/
MAX1487
MAX488/MAX490
MAX489/MAX491
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
__________Applications InformationThe MAX481/MAX483/MAX485/MAX487–MAX491 andMAX1487 are low-power transceivers for RS-485 and RS-422 communications. The MAX481, MAX485, MAX490,MAX491, and MAX1487 can transmit and receive at datarates up to 2.5Mbps, while the MAX483, MAX487,MAX488, and MAX489 are specified for data rates up to250kbps. The MAX488–MAX491 are full-duplex trans-ceivers while the MAX481, MAX483, MAX485, MAX487,and MAX1487 are half-duplex. In addition, Driver Enable(DE) and Receiver Enable (RE) pins are included on theMAX481, MAX483, MAX485, MAX487, MAX489,MAX491, and MAX1487. When disabled, the driver andreceiver outputs are high impedance.
MAX487/MAX1487:128 Transceivers on the Bus
The 48kΩ, 1/4-unit-load receiver input impedance of theMAX487 and MAX1487 allows up to 128 transceiverson a bus, compared to the 1-unit load (12kΩ inputimpedance) of standard RS-485 drivers (32 trans-ceivers maximum). Any combination of MAX487/MAX1487 and other RS-485 transceivers with a total of32 unit loads or less can be put on the bus. TheMAX481/MAX483/MAX485 and MAX488–MAX491 havestandard 12kΩ Receiver Input impedance.
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
8 _______________________________________________________________________________________
MAX488MAX490
TOP VIEW
1
2
3
4
RO
DI
GND
8
7
6
5
A
B
Z
Y
VCC
DIP/SO
R
DRt
Rt
VCC
5
6
7
8
RO
DI
GND
4
GND
DI
RO
3
2A
B
Y
Z
VCC
D R
R D
1
3VCC
4RO
2A
1
6
5
7
8
GND
DI
Y
ZB
µMAX
MAX488MAX490
NOTE: TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.
MAX489MAX491
DIP/SO
TOP VIEW
Rt
Rt
DE VCC
RE GND
VCC RE
GND DE
RO
DI
9
10
12
11B
A
Z
Y5
RO
NC
DI
2
1, 8, 13
3 6, 7
144
1
2
3
4
5
6
7
14
13
12
11
10
9
8
VCC
N.C.
N.C.
A
B
Z
Y
N.C.
RO
RE
DE
DI
GND
GND
R
D
D
R D
R
Figure 2. MAX488/MAX490 Pin Configuration and Typical Operating Circuit
Figure 3. MAX489/MAX491 Pin Configuration and Typical Operating Circuit
MAX483/MAX487/MAX488/MAX489:Reduced EMI and Reflections
The MAX483 and MAX487–MAX489 are slew-rate limit-ed, minimizing EMI and reducing reflections caused byimproperly terminated cables. Figure 12 shows the dri-ver output waveform and its Fourier analysis of a150kHz signal transmitted by a MAX481, MAX485,MAX490, MAX491, or MAX1487. High-frequency har-
monics with large amplitudes are evident. Figure 13shows the same information displayed for a MAX483,MAX487, MAX488, or MAX489 transmitting under thesame conditions. Figure 13’s high-frequency harmonicshave much lower amplitudes, and the potential for EMIis significantly reduced.
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
_______________________________________________________________________________________ 9
R
R
Y
Z
VOD
VOC
RECEIVEROUTPUT
TEST POINT
1kΩ
1kΩ
S1
S2
VCC
CRL15pF
DI
DE3V
Y
Z
CL1
CL2
A
B
RO
RE
RDIFFVID
OUTPUTUNDER TEST
500Ω S1
S2
VCC
CL
_________________________________________________________________Test Circuits
Figure 4. Driver DC Test Load Figure 5. Receiver Timing Test Load
Figure 6. Driver/Receiver Timing Test Circuit Figure 7. Driver Timing Test Load
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
10 ______________________________________________________________________________________
_______________________________________________________Switching Waveforms
DI3V
0V
Z
Y
VO0V
-VO
VO
1.5V
tPLH
1/2 VO
10%
tR
90% 90%
tPHL
1.5V
1/2 VO
10%
tF
VDIFF = V (Y) - V (Z)
VDIFF
tSKEW = | tPLH - tPHL |
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0V
Y, Z
VOL
Y, Z
0V
1.5V 1.5V
VOL +0.5V
VOH -0.5V2.3V
2.3V
tZL(SHDN), tZL tLZ
tZH(SHDN), tZH tHZ
DE
VOH
VOL
VID
-VID
1.5V
0V
1.5VOUTPUT
INPUT 0V
RO
A-BtPLHtPHL
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0V
VCCRO
RO0V
1.5V 1.5V
VOL + 0.5V
VOH - 0.5V1.5V
1.5V
tZL(SHDN), tZL tLZ
tZH(SHDN), tZH tHZ
RE
_________________Function Tables (MAX481/MAX483/MAX485/MAX487/MAX1487)
Figure 8. Driver Propagation Delays Figure 9. Driver Enable and Disable Times (except MAX488 andMAX490)
Figure 10. Receiver Propagation Delays Figure 11. Receiver Enable and Disable Times (except MAX488and MAX490)
Table 1. Transmitting Table 2. Receiving
INPUTS OUTPUT
RE DE A-B RO
0
0
0
1
0
0
0
0
> +0.2V
< -0.2V
Inputs open
X
1
0
1
High-Z*X = Don't careHigh-Z = High impedance
* Shutdown mode for MAX481/MAX483/MAX487
INPUTS OUTPUTS
RE DE DI Z Y
X
X
0
1
1
1
0
0
1
0
X
X
0
1
High-Z
High-Z*
1
0
High-Z
High-Z*X = Don't careHigh-Z = High impedance
* Shutdown mode for MAX481/MAX483/MAX487
Low-Power Shutdown Mode(MAX481/MAX483/MAX487)
A low-power shutdown mode is initiated by bringingboth RE high and DE low. The devices will not shutdown unless both the driver and receiver are disabled.In shutdown, the devices typically draw only 0.1µA ofsupply current.
RE and DE may be driven simultaneously; the parts areguaranteed not to enter shutdown if RE is high and DEis low for less than 50ns. If the inputs are in this statefor at least 600ns, the parts are guaranteed to entershutdown.
For the MAX481, MAX483, and MAX487, the tZH andtZL enable times assume the part was not in the low-power shutdown state (the MAX485/MAX488–MAX491and MAX1487 can not be shut down). The tZH(SHDN)and tZL(SHDN) enable times assume the parts were shutdown (see Electrical Characteristics).
It takes the drivers and receivers longer to becomeenabled 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
–R—E–
,DE inputs equal a logical 0,1 or 1,1 or 0, 0.)
Driver Output Protection Excessive output current and power dissipation causedby faults or by bus contention are prevented by twomechanisms. A foldback current limit on the outputstage provides immediate protection against short cir-cuits over the whole common-mode voltage range (seeTypical Operating Characteristics). In addition, a ther-mal shutdown circuit forces the driver outputs into ahigh-impedance state if the die temperature risesexcessively.
Propagation DelayMany digital encoding schemes depend on the differ-ence between the driver and receiver propagationdelay times. Typical propagation delays are shown inFigures 15–18 using Figure 14’s test circuit.
The difference in receiver delay times, | tPLH - tPHL |, istypically under 13ns for the MAX481, MAX485,MAX490, MAX491, and MAX1487 and is typically lessthan 100ns for the MAX483 and MAX487–MAX489.
The driver skew times are typically 5ns (10ns max) forthe MAX481, MAX485, MAX490, MAX491, andMAX1487, and are typically 100ns (800ns max) for theMAX483 and MAX487–MAX489.
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
______________________________________________________________________________________ 11
10dB/div
0Hz 5MHz500kHz/div
10dB/div
0Hz 5MHz500kHz/div
Figure 12. Driver Output Waveform and FFT Plot of MAX481/MAX485/MAX490/MAX491/MAX1487 Transmitting a 150kHzSignal
Figure 13. Driver Output Waveform and FFT Plot of MAX483/MAX487–MAX489 Transmitting a 150kHz Signal
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
12 ______________________________________________________________________________________
TTL INtR, tF < 6ns D R
100pF
B
100pF
A
RECEIVEROUT
R = 54Ω
Z
Y
500mV/div
20ns/div
A
B
RO
2V/div
VCC = 5VTA = +25°C 500mV/div
20ns/div
A
B
RO
2V/div
VCC = 5VTA = +25°C
500mV/div
400ns/div
A
B
RO
2V/div
VCC = 5VTA = +25°C
500mV/div
400ns/div
A
B
RO
2V/div
VCC = 5VTA = +25°C
Figure 14. Receiver Propagation Delay Test Circuit
Figure 15. MAX481/MAX485/MAX490/MAX491/MAX1487Receiver tPHL
Figure 16. MAX481/MAX485/MAX490/MAX491/MAX1487Receiver tPLH
Figure 17. MAX483, MAX487–MAX489 Receiver tPHL Figure 18. MAX483, MAX487–MAX489 Receiver tPLH
Line Length vs. Data RateThe RS-485/RS-422 standard covers line lengths up to4000 feet. For line lengths greater than 4000 feet, seeFigure 23.
Figures 19 and 20 show the system differential voltagefor the parts driving 4000 feet of 26AWG twisted-pairwire at 110kHz into 120Ω loads.
Typical ApplicationsThe MAX481, MAX483, MAX485, MAX487–MAX491, andMAX1487 transceivers are designed for bidirectional datacommunications on multipoint bus transmission lines.
Figures 21 and 22 show typical network applicationscircuits. These parts can also be used as l inerepeaters, with cable lengths longer than 4000 feet, asshown in Figure 23.
To minimize reflections, the line should be terminated atboth ends in its characteristic impedance, and stublengths off the main line should be kept as short as possi-ble. The slew-rate-limited MAX483 and MAX487–MAX489are more tolerant of imperfect termination.
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
______________________________________________________________________________________ 13
DI
VY-VZ
RO
5V
0V
1V
0V-1V
5V
0V
2µs/div
DI
VY-VZ
RO
5V
0V
1V
0V-1V
5V
0V
2µs/div
DI RO DE
RE
A
B
RE
RERE
RO
RO
RO
DI
DI
DI
DE
DE
DE
D D
D
RR
R
B B
B
AAA
120Ω 120Ω
D
R
MAX481MAX483MAX485MAX487MAX1487
Figure 19. MAX481/MAX485/MAX490/MAX491/MAX1487 SystemDifferential Voltage at 110kHz Driving 4000ft of Cable
Figure 20. MAX483, MAX487–MAX489 System DifferentialVoltage at 110kHz Driving 4000ft of Cable
Figure 21. MAX481/MAX483/MAX485/MAX487/MAX1487 Typical Half-Duplex RS-485 Network
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
14 ______________________________________________________________________________________
Figure 22. MAX488–MAX491 Full-Duplex RS-485 Network
120Ω 120ΩR
D
RO
RE
DE
DI
A
B
Y
120Ω 120ΩDI
DI DIRO RO
RO
DE DE
DE
RE
RE
RE
Z
Z
Z
Z
Y Y
Y
A A AB B
B
D D
D
R R
R
MAX489MAX491
NOTE: RE AND DE ON MAX489/MAX491 ONLY.
Figure 23. Line Repeater for MAX488–MAX491
120Ω
120Ω DATA IN
DATA OUT
R
D
ROREDE
DI
A
B
Z
Y
MAX488–MAX491
NOTE: RE AND DE ON MAX489/MAX491 ONLY.
Isolated RS-485For isolated RS-485 applications, see the MAX253 andMAX1480 data sheets.
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
______________________________________________________________________________________ 15
__Ordering Information (continued)
_________________Chip TopographiesMAX481/MAX483/MAX485/MAX487/MAX1487
N.C.
RO
0.054"(1.372mm)
0.080"(2.032mm)
DE
DI
GND
B
N.C.
VCC
A
RE
* Contact factory for dice specifications.
14 CERDIP-55°C to +125°CMAX489MJD14 SO-40°C to +85°CMAX489ESD14 Plastic DIP-40°C to +85°CMAX489EPDDice*0°C to +70°CMAX489C/D14 SO0°C to +70°CMAX489CSD14 Plastic DIP0°C to +70°CMAX489CPD8 CERDIP-55°C to +125°CMAX488MJA8 SO-40°C to +85°CMAX488ESA8 Plastic DIP-40°C to +85°CMAX488EPADice*0°C to +70°CMAX488C/D
8 SO0°C to +70°CMAX488CSA8 Plastic DIP0°C to +70°CMAX488CPA8 CERDIP-55°C to +125°CMAX487MJA8 SO-40°C to +85°CMAX487ESA8 Plastic DIP-40°C to +85°CMAX487EPADice*0°C to +70°CMAX487C/D
8 SO0°C to +70°CMAX487CSA8 Plastic DIP0°C to +70°CMAX487CPA8 CERDIP-55°C to +125°CMAX485MJA8 SO-40°C to +85°CMAX485ESA8 Plastic DIP-40°C to +85°CMAX485EPADice*0°C to +70°CMAX485C/D
8 SO0°C to +70°CMAX485CSA8 Plastic DIP0°C to +70°CMAX485CPA8 CERDIP-55°C to +125°CMAX483MJA8 SO-40°C to +85°CMAX483ESA8 Plastic DIP-40°C to +85°CMAX483EPA
8 CERDIP-55°C to +125°CMAX481MJA
8 Plastic DIP-40°C to +85°CMAX481EPA
PIN-PACKAGETEMP. RANGEPART
14 CERDIP-55°C to +125°CMAX491MJD14 SO-40°C to +85°CMAX491ESD14 Plastic DIP-40°C to +85°CMAX491EPDDice*0°C to +70°CMAX491C/D14 SO0°C to +70°CMAX491CSD14 Plastic DIP0°C to +70°CMAX491CPD8 CERDIP-55°C to +125°CMAX490MJA8 SO-40°C to +85°CMAX490ESA8 Plastic DIP-40°C to +85°CMAX490EPADice*0°C to +70°CMAX490C/D
8 Plastic DIP0°C to +70°CMAX490CPAPIN-PACKAGETEMP. RANGEPART
8 SO-40°C to +85°CMAX481ESA
8 µMAX0°C to +70°CMAX485CUA
8 µMAX0°C to +70°CMAX487CUA
8 µMAX0°C to +70°CMAX488CUA
8 SO0°C to +70°CMAX490CSA8 µMAX0°C to +70°CMAX490CUA
__Ordering Information (continued)
8 CERDIP-55°C to +125°CMAX1487MJA8 SO-40°C to +85°CMAX1487ESA8 Plastic DIP-40°C to +85°CMAX1487EPADice*0°C to +70°CMAX1487C/D
8 SO0°C to +70°CMAX1487CSA8 Plastic DIP0°C to +70°CMAX1487CPA
8 µMAX0°C to +70°CMAX1487CUA
8 µMAX0°C to +70°CMAX483CUA
Dice*0°C to +70°CMAX483C/D
8 SO0°C to +70°CMAX483CSA
8 Plastic DIP0°C to +70°CMAX483CPA
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
16 ______________________________________________________________________________________
TRANSISTOR COUNT: 248
SUBSTRATE CONNECTED TO GND
MAX488/MAX490
B
RO
0.054"(1.372mm)
0.080"(2.032mm)
N.C.
DI
GND
Z
A
VCC
Y
N.C.
_____________________________________________Chip Topographies (continued)
MAX489/MAX491
B
RO
0.054"(1.372mm)
0.080"(2.032mm)
DE
DI
GND
Z
A
VCC
Y
RE
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
______________________________________________________________________________________ 17
Package Information(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline informationgo to www.maxim-ic.com/packages.)
SO
ICN
.EP
SPACKAGE OUTLINE, .150" SOIC
11
21-0041 BREV.DOCUMENT CONTROL NO.APPROVAL
PROPRIETARY INFORMATION
TITLE:
TOP VIEW
FRONT VIEW
MAX
0.010
0.069
0.019
0.157
0.010
INCHES
0.150
0.007
E
C
DIM
0.014
0.004
B
A1
MIN
0.053A
0.19
3.80 4.00
0.25
MILLIMETERS
0.10
0.35
1.35
MIN
0.49
0.25
MAX
1.75
0.0500.016L 0.40 1.27
0.3940.386D
D
MINDIM
D
INCHES
MAX
9.80 10.00
MILLIMETERS
MIN MAX
16 AC
0.337 0.344 AB8.758.55 14
0.189 0.197 AA5.004.80 8
N MS012
N
SIDE VIEW
H 0.2440.228 5.80 6.20
e 0.050 BSC 1.27 BSC
C
HE
e B A1
A
D
0∞-8∞L
1
VARIATIONS:
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
18 ______________________________________________________________________________________
8LU
MA
XD
.EP
S
PACKAGE OUTLINE, 8L uMAX/uSOP
11
21-0036 JREV.DOCUMENT CONTROL NO.APPROVAL
PROPRIETARY INFORMATION
TITLE:
MAX0.043
0.006
0.014
0.120
0.120
0.198
0.026
0.007
0.037
0.0207 BSC
0.0256 BSC
A2 A1
ce
b
A
L
FRONT VIEW SIDE VIEW
E H
0.6±0.1
0.6±0.1
ÿ 0.50±0.1
1
TOP VIEW
D
8
A2 0.030
BOTTOM VIEW
16∞
S
b
L
HE
De
c
0∞
0.010
0.116
0.116
0.188
0.016
0.005
84X S
INCHES
-
A1
A
MIN
0.002
0.950.75
0.5250 BSC
0.25 0.36
2.95 3.05
2.95 3.05
4.78
0.41
0.65 BSC
5.03
0.66
6∞0∞
0.13 0.18
MAXMIN
MILLIMETERS
- 1.10
0.05 0.15
α
α
DIM
Package Information (continued)(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline informationgo to www.maxim-ic.com/packages.)
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. 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.
MA
X4
81
/MA
X4
83
/MA
X4
85
/MA
X4
87
–MA
X4
91
/MA
X1
48
7
PD
IPN
.EP
S
Package Information (continued)(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline informationgo to www.maxim-ic.com/packages.)