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19-2217; Rev 1; 2/03
+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers
General Description
The MAX3460-MAX3464 are high-speed differential bus transceivers for RS-485 and RS-422 communications. They are designed to meet TIA/EIA-422-B, TIA/EIA-485-A, V.11, and X.27 standards. The transceiver complies with the Profibus specification providing +2.1V output level with a 54 load, 20Mbps data rate, and output skew less than 2ns. Each part contains one three-state differential line driver and one differential input line receiver. The devices operate from a +5V supply and feature true fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. This enables all receiver outputs on a terminated bus to output logic highs when all transmitters are disabled. All devices feature a 1/4 standard unit load receiver input impedance that allows 128 transceivers on the bus. Driver and receiver propagation delays are guaranteed under 20ns for multidrop, clock distribution applications. Drivers are short-circuit current limited and are protected against excessive power dissipation by thermal shutdown circuitry. The driver and receiver feature active-high and active-low enables, respectively, that can be connected together externally to serve as a direction control. o Guaranteed 20Mbps Data Rate o 20ns Transmitter and Receiver Propagation Delay o 2ns Transmitter and Receiver Skew o High Differential Driver Output Level (2.1V on 54) o Hot-Swap Versions o 1A Shutdown Supply Current o Low Supply Current Requirements (2.5mA typ) o Allow Up to 128 Transceivers on the Bus o True Fail-Safe Receiver while Maintaining EIA/TIA485 Compatibility o Designed for Multipoint Transmissions on Long or Noisy Bus Lines o Full Duplex and Half Duplex Versions Available o Phase Controls to Correct for Twisted-Pair Reversal for 14-Pin Versions o Current-Limiting and Thermal Shutdown for Driver Overload Protection
Features
o Recommended for Profibus Applications
MAX3460-MAX3464
Applications
High-Speed RS-485 Communications High-Speed RS-422 Communications Level Translators Industrial-Control Local Area Networks Profibus Applications
PART MAX3460CSD MAX3460CPD MAX3460ESD MAX3460EPD
Ordering Information
TEMP RANGE 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 14 SO 14 Plastic DIP 14 SO 14 Plastic DIP
Ordering Information continued at end of data sheet. Pin Configurations appear at end of data sheet.
Selector Guide
PART NUMBER MAX3460 MAX3461 MAX3462 MAX3463 MAX3464 HALF/FULL DUPLEX Full Full Full Half Half RECEIVER/ DRIVER ENABLE Yes Yes No Yes Yes LOWPOWER SHUTDOWN Yes Yes No Yes Yes HOT SWAP Yes No No Yes No RECEIVER/ DRIVER PHASE SELECT Yes Yes No No No INDEPENDENT SHDN PIN Yes Yes No No No PIN COUNT 14 14 8 8 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.
+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers MAX3460-MAX3464
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC) to GND ..................................-0.3V to +6V Control Input Voltage (RE, DE, DI, SHDN, TXP, RXP) to GND....................................................-0.3V to (VCC + 0.3V) Driver Output Voltage (Y, Z) to GND .........................-8V to +13V Receiver Input Voltage (A, B) to GND.......................-8V to +13V Differential Driver Output Voltage (Y - Z) ...............................8V Differential Receiver Input (A - B) ..........................................8V Receiver Output Voltage (RO) to GND.......-0.3V to (VCC + 0.3V) Output Driver Current (Y, Z) ...........................................250mA Continuous Power Dissipation (TA = +70C) 8-Pin SO (derate 5.88mW/C above +70C)................471mW 8-Pin DIP (derate 9.09mW/C above +70C) ...............727mW 14-Pin SO (derate 8.33mW/C above +70C)..............667mW 14-Pin DIP (derate 10mW/C above +70C) ................800mW Operating Temperature Range MAX346_C__ ......................................................0C to +70C MAX346_E__....................................................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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.
ELECTRICAL CHARACTERISTICS
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) (Note 1)
PARAMETER Power-Supply Range DRIVER Differential Driver Output (no load) Differential Driver Output Change in Magnitude of Differential Output Voltage Driver Common-Mode Output Voltage Change in Magnitude of Common-Mode Voltage Input High Voltage Input Low Voltage Input Hysteresis Output Leakage (Y and Z) Full Duplex Input Current Pulldown Current Driver Short-Circuit Output Current (Note 3) Driver Short-Circuit Foldback Output Current (Note 3) Thermal Shutdown Threshold RECEIVER Differential Input Capacitance Input Current (A and B) Full Duplex Receiver Differential Threshold Voltage CA, B IA, B VTH DE = GND, VCC = GND or 5.25V -7V VCM 12V VIN = +12V VIN = -7V -200 -200 -125 -50 8 250 pF A mV IOSD IOSFD VOD VOD VOD VOC VOC VIH VIL VHYS IO IIN Figure 5, R = Figure 5, R = 27 Figure 5, R = 50 or 27 (Note 2) Figure 5, R = 50 or 27 Figure 5, R = 50 or 27 (Note 2) DE, DI, RE, SHDN DE, DI, RE, SHDN DE, DI, RE, SHDN DE = GND, VCC = GND or +5.25V DI, RE, DE, SHDN RXP = TXP = VCC 0 VOUT 12V, output low -7V VOUT VCC, output high (VCC - 1V) VOUT 12V, output low -7V VOUT 1V, output high 140 -250 +25 -25 5 15 VIN = +12V VIN = -7V -100 1 30 +250 50 +125 2.0 0.8 2.1 0.2 3 0.2 VCC V V V V V V V mV A A A mA mA C SYMBOL VCC CONDITIONS MIN 4.75 TYP MAX 5.25 UNITS V
2
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+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) (Note 1)
PARAMETER Receiver Input Hysteresis Receiver Output High Voltage Receiver Output Low Voltage Three-State Output Current at Receiver Receiver Input Resistance Receiver Output Short-Circuit Current SUPPLY CURRENT Normal Operation (static condition) Supply Current in SHDN SWITCHING CHARACTERISTICS Driver Propagation Delay Driver Differential Output Rise or Fall Time Driver Output Skew |tPLH - tPHL| Maximum Data Rate Driver Enable to Output High Driver Enable to Output Low Driver Disable Time from Low Driver Disable Time from High Receiver Propagation Delay Receiver Output Skew |tPLH - tPHL| Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable Time from Low Receiver Disable Time from High tZH tZL tLZ tHZ tPLH tPHL tSKEW tZL tZH tLZ tHZ Figures 8 and 9, S2 closed, RL = 500, CL = 50pF Figures 8 and 9, S1 closed, RL = 500, CL = 50pF Figures 8 and 9, S1 closed, RL = 500, CL = 50pF Figures 8 and 9, S2 closed, RL = 500, CL = 50pF Figure 10, CL = 15pF (Note 4) Figure 10, CL = 15pF, RXP = GND or floating (Note 4) Figures 8 and 11, RL = 1k, CL = 15pF, S1 closed (Note 4) Figures 8 and 11, RL = 1k, CL = 15pF, S2 closed (Note 4) Figures 8 and 11, RL = 1k, CL = 15pF, S1 closed (Note 4) Figures 8 and 11, RL = 1k, CL = 15pF, S2 closed (Note 4) tPLH tPHL tR tF tSKEW Figures 6 and 7, RDIFF = 54, CL = 50pF Figures 6 and 7, RDIFF = 54, CL = 50pF Figures 6 and 7, RDIFF = 54, CL = 50pF, TXP = GND or floating 20 100 100 100 100 20 2 100 100 100 100 20 20 2 ns ns ns Mbps ns ns ns ns ns ns ns ns ns ns IQ ISHDN No load, DI = VCC or DI = GND DE = GND and RE = VCC, or SHDN = VCC 2.5 1 4 10 mA A SYMBOL VTH VOH VOL IOZR RIN IOSR V A + VB = 0 IO = -4mA, VA - VB = VTH IO = 4mA, VB - VA = VTH 0 VO VCC -7V VCM 12V 0 VRO VCC 48 7 95 VCC - 1.5 0.4 1 CONDITIONS MIN TYP 20 MAX UNITS mV V V A k mA
MAX3460-MAX3464
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+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers MAX3460-MAX3464
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) (Note 1)
PARAMETER 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 SYMBOL tSHDN tZH (SHDN) tZL (SHDN) tZH (SHDN) tZL (SHDN) (Note 5) Figures 8 and 9, RL = 500, CL = 50pF, S2 closed (Note 5) Figures 8 and 9, RL = 500, CL = 50pF, S1 closed (Note 5) Figures 8 and 11, RL = 1k, CL = 15pF, S2 closed (Notes 4, 5) Figures 8 and 11, RL = 1k, CL = 15pF, S1 closed (Notes 4, 5) CONDITIONS MIN 50 TYP MAX 800 4 4 4 4 UNITS ns s s s s
Note 1: All currents into the device are positive; all currents out of the device are negative. All voltages are referenced to device ground, unless otherwise noted. Note 2: VOD and VOC are the changes in VOD and VOC, respectively, when the DI input changes state. Note 3: The short-circuit output current applies to peak current just prior to foldback-current limiting; the short-circuit foldback output current applies during current limiting to allow a recovery from bus contention. Note 4: Capacitive load includes test probe and fixture capacitance. Note 5: Shutdown is enabled by bringing RE high and DE low or by bringing SHDN high. If the enable inputs are in this state for less than 50ns, the device is guaranteed not to enter shutdown. If the enable inputs are in this state for at least 800ns, the device is guaranteed to have entered shutdown.
Typical Operating Characteristics
(VCC = +5V, TA = +25C, unless otherwise noted.)
NO LOAD SUPPLY CURRENT vs. TEMPERATURE
MAX3460-64 toc01
OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE
MAX3460-64 toc02
OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE
MAX3460-64 toc03
2.40 NO LOAD SUPPLY CURRENT (mA) 2.35 2.30 2.25 2.20 DE = GND 2.15 2.10 2.05 2.00 -40 -20 40 TEMPERATURE (C) 0 20 60 80 DE = VCC
60 50 OUTPUT CURRENT (mA) 40 30 20 10 0 0
35 30 OUTPUT CURRENT (mA) 25 20 15 10 5 0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 OUTPUT LOW VOLTAGE (V)
0
1
2
3
4
5
OUTPUT HIGH VOLTAGE (V)
4
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+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers
Typical Operating Characteristics (continued)
(VCC = +5V, TA = +25C, unless otherwise noted.)
MAX3460-MAX3464
SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE
MAX3460-64 toc04
RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE
MAX3460-64 toc05
RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE
IO = -4mA
MAX3460-64 toc06
50 SHUTDOWN SUPPLY CURRENT (nA)
4.90 4.85 OUTPUT HIGH VOLTAGE (V) 4.80 4.75 4.70 4.65
RECEIVER OUTPUT LOW VOLTAGE (mV)
IO = 4mA 140
40
30
120
20
100
10
0 -40 -15 10 35 60 85 TEMPERATURE (C)
80 -40 -15 10 35 60 85 TEMPERATURE (C)
4.60 -40 -15 10 35 60 85 TEMPERATURE (C)
RECEIVER PROPAGATION DELAY vs. TEMPERATURE
MAX3460-64 toc07
DRIVER PROPAGATION DELAY vs. TEMPERATURE
MAX3460-64 toc08
DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE
RDIFF = 54
MAX3460-64 toc09
11
12
4.0
RDIFF = 54 CL = 50pF
PROPAGATION DELAY (ns)
9
OUTPUT VOLTAGE (V)
10
PROPAGATION DELAY (ns)
10
3.5
8
3.0
8
6
2.5
7 -40 -15 10 35 60 85 TEMPERATURE (C)
4 -40 -15 10 35 60 85 TEMPERATURE (C)
2.0 -40 -15 10 35 60 85 TEMPERATURE (C)
DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX3460-64 toc10
OUTPUT CURRENT vs. DRIVER OUTPUT LOW VOLTAGE
MAX3460-64 toc11
OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGE
MAX3460-64 toc12
100
200
-160
160 OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
10
120
OUTPUT CURRENT (mA)
-120
-80
80
1
40
-40
0.1 0 1 2 3 4 5 DIFFERENTIAL OUTPUT VOLTAGE (V)
0 0 3 6 9 12 OUTPUT LOW VOLTAGE (V)
0 -7 -5 -3 -1 1 3 5 OUTPUT HIGH VOLTAGE (V)
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+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers MAX3460-MAX3464
Typical Operating Characteristics (continued)
(VCC = +5V, TA = +25C, unless otherwise noted.)
DRIVER AND RECEIVER PROPAGATION DELAYS
MAX3460-64 toc13
ENABLE RESPONSE TIME
MAX3460-64 toc14
EYE DIAGRAM
5V/div
MAX3460-64 toc15
DE DI 0 5V/div 0
Y, Z 0
2V/div
Y, Z
1V/div
RO 0 10ns/div
5V/div
0 20ns/div 10ns/div
Pin Description
PIN MAX3460/ MAX3461 MAX3462 MAX3463/ MAX3464 HALF DUPLEX -- 1 2 SHDN RO RE Shutdown. Drive SHDN high to enter low-power shutdown mode. Receiver Output. When RE is low and (A - B) -50mV, RO is high; if (A - B) -200mV, RO is low. Receiver Output Enable. Drive RE low to enable RO; RO is high impedance when RE is high. Drive RE high and DE low to enter low-power shutdown mode. Driver Output Enable. Drive DE high to enable driver output. These outputs are high impedance when DE is low. Drive RE high and DE low to enter lowpower shutdown mode. Driver Input. With DE high, a low on DI forces the noninverting output low and the inverting output high. Similarly, a high on DI forces the noninverting output high and the inverting output low. Ground Transmitter Phase. Connect TXP to GND, or leave unconnected for normal transmitter phase/polarity. Connect TXP to VCC to invert the transmitter phase/polarity. TXP has an internal 15A pulldown. Noninverting Driver Output Inverting Driver Output Inverting Receiver Input Noninverting Receiver Input Receiver Phase. Connect RXP to GND, or leave unconnected for normal receiver phase/polarity. Connect RXP to VCC to invert the receiver phase/polarity. RXP has an internal 15A pulldown. Positive Supply: +4.75V VCC +5.25V. Bypass VCC to GND with a 0.1F capacitor. Inverting Receiver Input and Inverting Driver Output Noninverting Receiver Input and Noninverting Driver Output NAME FUNCTION
FULL DUPLEX 1 2 3 -- 2 --
4
--
3
DE
5 6, 7 8 9 10 11 12 13 14 -- --
3 4 -- 5 6 7 8 -- 1 -- --
4 5 -- -- -- -- -- -- 8 7 6
DI GND TXP Y Z B A RXP VCC B A
6
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+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers
Function Tables
MAX3460/MAX3461
TRANSMITTING INPUTS RE X X 0 1 X DE 1 1 0 0 X DI 1 0 X X X SHDN 0 0 0 X 1 OUTPUTS Z 0 1 High-Z Y 1 0 High-Z RECEIVING INPUTS A-B RECEIVING INPUTS RE 0 0 0 1 1 X DE X X X 1 0 X A-B -0.05V -0.2V Open/Shorted X X X SHDN 0 0 0 0 X 1 OUTPUT RO 1 0 1 High-Z Shutdown Shutdown INPUTS RE X X 0 1 DE 1 1 0 0 DI 1 0 X X RECEIVING INPUTS RE 0 0 0 1 1 DE X X X 1 0 A-B -0.05V -0.2V Open/Shorted X X OUTPUT RO 1 0 1 High-Z Shutdown B 0 1 High-Z Shutdown TRANSMITTING OUTPUTS A 1 0 High-Z -0.05V -0.2V Open/Shorted OUTPUT RO 1 0 1 INPUT DI 1 0 Z 0 1
MAX3460-MAX3464
MAX3462
TRANSMITTING OUTPUTS Y 1 0
Shutdown Shutdown
MAX3463/MAX3464
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+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers MAX3460-MAX3464
Pin Configurations and Typical Operating Circuit
TOP VIEW
DE 4 SHDN 1 RO RE 2 3 R 14 VCC 13 RXP 12 A 11 B 10 Z D GND 6 GND 7 9 8 Y TXP RO TXP RXP 2 8 13 3 6, 7 GND R 12 11 B A Rt D DI DI 5 D VCC 14 9 10 Z 0.1F Y Rt R RO VCC RE
MAX3460 MAX3461
DE 4 DI 5
DIP/SO
RE
GND
DE
Figure 1. MAX3460/MAX3461 Pin Configuration and Typical Full-Duplex Operating Circuit
TOP VIEW
VCC 1 5 VCC 1 RO DI 2 3 D GND 4 5 Y RO R 8 7 6 A B Z 2 R 8 7 DI 3 D 6
0.1F
VCC
MAX3462
Y Rt Z R RO
A Rt B D DI
DIP/SO
4 GND GND
Figure 2. MAX3462 Pin Configuration and Typical Full-Duplex Operating Circuit
TOP VIEW
0.1F RO 1 RE 2 DE 3 DI 4 D R 8 VCC 7B 6A 5 GND RO 1 RE 2 DE 3 DI 4 D R VCC 8 7B 6 A 5 GND Rt Rt A D RO
MAX3463 MAX3464
B
DE
R
DI
DIP/SO
NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.
RE
Figure 3. MAX3463/MAX3464 Pin Configuration and Typical Full-Duplex Operating Circuit 8 _______________________________________________________________________________________
+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers
Detailed Description
The MAX3460-MAX3464 high-speed transceivers for RS-485/RS-422 communication contain one driver and one receiver. These devices feature true fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted, or when they are connected to a terminated transmission line with all drivers disabled (see the True Fail-Safe section). The MAX3460-MAX3464's driver slew rates allow transmit speeds up to 20Mbps. The MAX3463 and MAX3464 are half-duplex transceivers, while the MAX3460, MAX3461, and MAX3462 are full-duplex transceivers. All of these parts operate from a single +5V supply. Drivers are output short-circuit current limited. Thermal shutdown circuitry protects drivers against excessive power dissipation. When activated, the thermal shutdown circuitry places the driver outputs into a high-impedance state. The MAX3460 and MAX3463 devices have a hot-swap input structure that prevents disturbances on the differential signal lines when a circuit board is plugged into a "hot" backplane (see Hot Swap section). All devices have output levels that are compatible with Profibus standards. level. Leakage currents up to 10A from the highimpedance output could cause DE to drift to an incorrect logic state. Additionally, parasitic circuit board capacitance could cause coupling of VCC or GND to DE. These factors could improperly enable the driver. When VCC rises, an internal pulldown circuit holds DE low for around 15s. After the initial power-up sequence, the pulldown circuit becomes transparent, resetting the hot-swap tolerable input. Hot-Swap Input Circuitry The MAX3460/MAX3463 enable inputs feature hot-swap capability. At the input there are two NMOS devices, M1 and M2 (Figure 4). When VCC ramps from 0, an internal 15s timer turns on M2 and sets the SR latch, which also turns on M1. Transistors M2, a 2mA current sink, and M1, a 100A current sink, pull DE to GND through a 5.6k resistor. M2 is designed to pull DE to the disabled state against an external parasitic capacitance up to 100pF that can drive DE high. After 15s, the timer deactivates M2 while M1 remains on, holding DE low against three-state leakages that can drive DE high. M1 remains on until an external source overcomes the required input current. At this time, the SR latch resets and M1 turns off. When M1 turns off, DE reverts to a standard, high-impedance CMOS input. Whenever VCC drops below 1V, the hot-swap input is reset. For RE there is a complimentary circuit employing two PMOS devices pulling RE to VCC.
MAX3460-MAX3464
True Fail-Safe
The MAX3460-MAX3464 guarantee a logic-high receiver output when the receiver inputs are shorted or open, or when they are connected to a terminated transmission line with all drivers disabled. This is done by setting the receiver threshold between -50mV and -200mV. If the differential receiver input voltage (A - B) is greater than or equal to -50mV, RO is logic high. If A - B is less than or equal to -200mV, RO is logic low. In the case of a terminated bus with all transmitters disabled, the receiver's differential input voltage is pulled to 0V by the termination. With the receiver thresholds of the MAX3460-MAX3464, this results in a logic high with a 50mV minimum noise margin. Unlike previous true fail-safe devices, the -50mV to -200mV threshold complies with the 200mV EIA/TIA-485 standard.
VCC 15s TIMER TIMER
Hot-Swap Capability
Hot-Swap Inputs When circuit boards are inserted into a "hot" or powered backplane, disturbances to the enable and differential receiver inputs can lead to data errors. Upon initial circuit board insertion, the processor undergoes its power-up sequence. During this period, the output drivers are high impedance and are unable to drive the DE input of the MAX3460/MAX3463 to a defined logic
5.6k EN 100A M1 2mA M2 DE (HOT SWAP)
Figure 4. Simplified Structure of the Driver Enable Pin (DE)
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+5V, Fail-Safe, 20Mbps, Profibus RS-485/ MAX3460-MAX3464
Y R VOD R Z VOC OUTPUT UNDER TEST CL S2 RL S1
VCC
Figure 8. Enable/Disable Timing Test Load
Figure 5. Driver DC Test Load
DE
3V 1.5V 0 tZL(SHDN), tZL Y, Z VOL 2.3V OUTPUT NORMALLY LOW VOL + 0.5V tLZ 1.5V
Y, Z
OUTPUT NORMALLY HIGH 2.3V VOH - 0.5V tHZ
3V DE DI Y VID Z RDIFF CL
0 tZH(SHDN), tZH
Figure 9. Driver Enable and Disable Times
= 1MHz, tR 3ns, tF 3ns VOH RO 1.5V VOL 1V -1V A B tPHL INPUT OUTPUT tPLH 1.5V
Figure 6. Driver Timing Test Circuit
Figure 10. Receiver Propagation Delays
= 1MHz, tR 3ns, tF 3ns 3V DI 0 1.5V tPLH tPHL 1.5V 1/2 VO
tZL(SHDN), tZL tLZ VOL + 0.5V VCC RO RE 0 3V 1.5V 1.5V
Z VO Y 1/2 VO VDIFF = V (Y) - V (Z) VO VDIFF 0 -VO 90% 10% tR tSKEW = | tPLH - tPHL | tF 90% 10%
1.5V
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH RO 0 tZH(SHDN), tZH tHZ 1.5V VOH - 0.5V
Figure 7. Driver Propagation Delays
Figure 11. Receiver Enable and Disable Times
10
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+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers
high-impedance state if the die temperature exceeds +140C.
B ATE VID A R RECEIVER OUTPUT
MAX3460-MAX3464
Propagation Delay
Many digital encoding schemes depend on the difference between the driver and receiver propagation delay times. Typical propagation delays are shown in the Typical Operating Characteristics. The difference in receiver delay times, |tPLH - tPHL|, is a maximum of 2ns. The driver skew time |tPLH - tPHL| is also a maximum of 2ns.
Figure 12. Receiver Propagation Delay Test Circuit
Typical Applications
The MAX3460-MAX3464 transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figures 13 and 14 show typical network applications circuits. 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.
Applications Information
128 Transceivers on the Bus
The standard RS-485 receiver input impedance is 12k (one-unit load), and the standard driver can drive up to 32 unit loads. The MAX3460-MAX3464 family of transceivers has a 1/4-unit-load receiver input impedance (48k), allowing up to 128 transceivers to be connected in parallel on one communication line. Any combination of these devices and/or other RS-485 transceivers with a total of 32 unit loads or less can be connected to the line.
Profibus Termination
The MAX3460-MAX3464 are designed for driving Profibus termination networks. With a worst-case loading of two termination networks with 220 termination impedance and 390 pullups and pulldowns, the drivers can drive VA-B> 2.1V output.
Low-Power Shutdown Mode (except MAX3462)
Low-power shutdown mode is initiated by bringing SHDN high (MAX3460/MAX3461), or both RE high and DE low. In shutdown, the devices typically draw only 1A of supply current. RE and DE can 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 800ns, the parts are guaranteed to enter shutdown.
Chip Information
TRANSISTOR COUNT: 610 PROCESS: BiCMOS
Ordering Information (continued)
PART MAX3461CSD MAX3461CPD MAX3461ESD MAX3461EPD MAX3462CSA MAX3462CPA MAX3462ESA MAX3462EPA MAX3463CSA MAX3463CPA MAX3463ESA MAX3463EPA MAX3464CSA MAX3464CPA MAX3464ESA MAX3464EPA TEMP RANGE 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 14 SO 14 Plastic DIP 14 SO 14 Plastic DIP 8 SO 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO 8 Plastic DIP
Driver Output Protection
Two mechanisms prevent excessive output current and power dissipation caused by faults or by bus contention. The first, 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). The second, a thermal shutdown circuit, forces the driver outputs into a
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11
+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers MAX3460-MAX3464
120 DI D B 120 B D DE
DE
A R
B
A
B
A
A R
DI
RO RE
RO RE
R
R D
MAX3463 MAX3464 (HALF-DUPLEX)
D
DI
DE
RO
RE
DI
DE
RO
RE
Figure 13. Typical Half-Duplex RS-485 Network
A 120 RO RE DE Z DI D Y Y Z B A B Y Z 120 120 R B 120
Y D Z DE RE R A RO DI
B
R D D
R
MAX3460 MAX3461 MAX3462 (FULL-DUPLEX)
DI
DE RE
RO
DI
DE RE
RO
NOTE: RE AND DE ON MAX3460/MAX3461/MAX3462 ONLY
Figure 14. Typical Full-Duplex RS-485 Network
12
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+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers
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
MAX3460-MAX3464
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 C
A e B A1
0 -8 L
FRONT VIEW
SIDE VIEW
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE, .150" SOIC
APPROVAL DOCUMENT CONTROL NO. REV.
21-0041
B
1 1
______________________________________________________________________________________
13
+5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers MAX3460-MAX3464
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.)
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.
14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
PDIPN.EPS

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