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| 19-3038; Rev 2; 8/09 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers General Description The MAX3465-MAX3469 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 minimum output level with a 54 load, 40Mbps 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. Up to 40Mbps Data Rate 15ns Transmitter Propagation Delay 20ns Receiver Propagation Delay 2ns Transmitter and Receiver Skew High Differential Driver Output Level (2.1V on 54) Hot-Swap Versions 1A Shutdown Supply Current Low Supply Current Requirements (2.5mA, typ) Allow Up to 128 Transceivers on the Bus True Fail-Safe Receiver while Maintaining EIA/TIA485 Compatibility Designed for Multipoint Transmissions on Long or Noisy Bus Lines Full-Duplex and Half-Duplex Versions Available Phase Controls to Correct for Twisted-Pair Reversal for 14-Pin Versions Current-Limiting and Thermal Shutdown for Driver Overload Protection Features Recommended for Profibus Applications MAX3465-MAX3469 Applications High-Speed RS-485 Communications High-Speed RS-422 Communications Level Translators Industrial-Control Local Area Networks Profibus Applications PART MAX3465CSD MAX3465CPD MAX3465ESD MAX3465EPD 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 MAX3465 MAX3466 MAX3467 MAX3468 MAX3469 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 Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers MAX3465-MAX3469 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 CA, B IA, B Between A and B DE = GND, VCC = GND or +5.25V VIN = +12V VIN = -7V -200 8 +250 pF A 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 _______________________________________________________________________________________ +5V, Fail-Safe, 40Mbps, 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 Differential Threshold Voltage 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 ESD Protection 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| Driver Output Transition Skew Maximum Data Rate Driver Enable to Output High Driver Enable to Output Low Driver Disable Time from Low Driver Disable to Output High Driver Enable Skew Time Driver Disable Skew Time Receiver Propagation Delay tZH tZL tLZ tHZ |tZL - tZH| |tZL - tZH| tPLH tPHL 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 RL = 500, CL = 50pF, S1 closed (Figures 8 and 9), output low RL = 500, CL = 50pF, S2 closed (Figures 8 and 9), output high Figure 10, CL = 15pF (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 open Guaranteed by design 30 40 30 30 30 30 5 5 20 15 10 2 1 ns ns ns ns Mbps 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 VTH VOH VOL IOZR RIN IOSR CONDITIONS -7V VCM +12V VCM = 0 IO = -4mA, VA - VB = VTH IO = 4mA, VB - VA = VTH 0 VO VCC -7V VCM +12V 0 VRO VCC A, B, Y, and Z pins (MAX3467/MAX3468/MAX3469) 48 7 6 95 VCC - 1.5 0.4 1 MIN -200 TYP -125 20 MAX -50 UNITS mV mV V V A k mA kV MAX3465-MAX3469 _______________________________________________________________________________________ 3 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers MAX3465-MAX3469 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 Output Skew Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable Time from Low Receiver Disable Time from High 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 |tPLH tPHL| tZL tZH tLZ tHZ tSHDN tZH (SHDN) tZL (SHDN) tZH (SHDN) tZL (SHDN) CONDITIONS Figure 10, CL = 15pF, RXP = GND or open (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) (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) 50 MIN TYP MAX 2 30 30 30 30 800 4 4 4 4 UNITS ns ns ns ns ns 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 OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE MAX3465 toc02 (VCC = +5V, TA = +25C, unless otherwise noted.) NO-LOAD SUPPLY CURRENT vs. TEMPERATURE 2.45 2.40 2.35 2.30 DE = GND 2.25 2.20 2.15 2.10 -40 -20 0 20 40 60 80 TEMPERATURE (C) 10 0 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) DE = VCC MAX3465 toc01 OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE 60 50 OUTPUT CURRENT (mA) 40 30 20 35 30 OUTPUT CURRENT (mA) 25 20 15 10 5 0 NO-LOAD SUPPLY CURRENT (mA) 0 1 2 3 4 5 OUTPUT HIGH VOLTAGE (V) 4 _______________________________________________________________________________________ MAX3465 toc03 2.50 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers Typical Operating Characteristics (continued) (VCC = +5V, TA = +25C, unless otherwise noted.) MAX3465-MAX3469 SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE MAX3465 toc04 RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE MAX3465 toc05 RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE RECEIVER OUTPUT HIGH VOLTAGE (mV) IO = 4mA 4.85 4.80 4.75 4.70 4.65 4.60 MAX3465 toc06 300 SHUTDOWN SUPPLY CURRENT (nA) 250 200 150 100 50 0 -40 -15 10 35 60 200 RECEIVER OUTPUT LOW VOLTAGE (mV) IO = -4mA 175 150 125 100 75 50 4.90 85 -40 -15 10 35 60 85 -40 -15 10 35 60 85 TEMPERATURE (C) TEMPERATURE (C) TEMPERATURE (C) RECEIVER PROPAGATION DELAY vs. TEMPERATURE MAX3465 toc07 DRIVER PROPAGATION DELAY vs. TEMPERATURE MAX3465 toc08 DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE RDIFF = 54 MAX3465 toc09 20 12 RDIFF = 54 PROPAGATION DELAY (ns) 10 3.5 PROPAGATION DELAY (ns) 18 OUTPUT VOLTAGE (V) 3.0 16 8 14 2.5 12 6 10 -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 MAX3465 toc10 OUTPUT CURRENT vs. DRIVER OUTPUT LOW VOLTAGE (TA = +25C) MAX3465 toc11 OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGE MAX3465 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) _______________________________________________________________________________________ 5 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers MAX3465-MAX3469 Typical Operating Characteristics (continued) (VCC = +5V, TA = +25C, unless otherwise noted.) DRIVER AND RECEIVER PROPAGATION DELAYS MAX3465 toc13 ENABLE RESPONSE TIME MAX3465 toc14 EYE DIAGRAM MAX3465 toc15 DI 5V/div 5V/div DE Y, Z 2V/div Y, Z 1V/div Y, Z 1V/div RO 5V/div RDIFF = 54 DATA RATE = 20Mbps 10ns/div RDIFF = 54 20ns/div RDIFF = 54 DATA RATE = 20Mbps 10ns/div Pin Description PIN FULL DUPLEX MAX3465/ MAX3466 1 2 3 MAX3467 -- 2 -- HALF DUPLEX MAX3468/ MAX3469 -- 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. The driver outputs are high impedance when DE is low. Drive RE high and DE low to enter low-power shutdown mode. Do not leave RE unconnected when using the MAX3466 or MAX3469. 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 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 _______________________________________________________________________________________ +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers Function Tables MAX3465/MAX3466 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 RE X X 0 1 INPUTS 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 -0.05V -0.2V Open/Shorted OUTPUT RO 1 0 1 INPUT DI 1 0 Z 0 1 MAX3465-MAX3469 MAX3467 TRANSMITTING OUTPUTS Y 1 0 Shutdown Shutdown MAX3468/MAX3469 TRANSMITTING OUTPUTS A 1 0 High-Z _______________________________________________________________________________________ 7 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers MAX3465-MAX3469 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 MAX3465 MAX3466 DE 4 DI 5 DIP/SO RE GND DE Figure 1. MAX3465/MAX3466 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 MAX3467 Y Rt Z R RO A Rt B D DI DIP/SO 4 GND GND Figure 2. MAX3467 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 MAX3468 MAX3469 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. MAX3468/MAX3469 Pin Configuration and Typical Full-Duplex Operating Circuit 8 _______________________________________________________________________________________ +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers Detailed Description The MAX3465-MAX3469 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 MAX3465-MAX3469's driver slew rates allow transmit speeds up to 40Mbps. The MAX3468 and MAX3469 are half-duplex transceivers, while the MAX3465, MAX3466, and MAX3467 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 MAX3465 and MAX3468 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 the Hot-Swap Capability section). All devices have output levels that are compatible with Profibus standards. defined logic level. Leakage currents up to 10A from the high-impedance 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. MAX3465-MAX3469 True Fail-Safe The MAX3465-MAX3469 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 MAX3465-MAX3469, 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. Hot-Swap Input Circuitry The MAX3465/MAX3468 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 complementary circuit employing two PMOS devices pulling to VCC. 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 processor output drivers are high impedance and are unable to drive the DE input of the MAX3465/MAX3468 to a 5.6k EN 100A M1 2mA M2 DE (HOT SWAP) Figure 4. Simplified Structure of the Driver Enable Pin (DE) _______________________________________________________________________________________ 9 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers MAX3465-MAX3469 Y R VOD R Z VOC 3V DE 0V tZL(SHDN), tZL Y, Z VOL 50% OUTPUT NORMALLY LOW VOL + 0.5V tLZ 1.5V 1.5V Y, Z 50% 0V OUTPUT NORMALLY HIGH VOH - 0.5V tHZ Figure 5. Driver DC Test Load tZH(SHDN), tZH Figure 9. Driver Enable and Disable Times 3V DE DI Y VID Z RO VOL 1V A B tPHL INPUT -1V RDIFF CL VOH 1.5V f = 1MHz, tR 3ns, tF 3ns 1.5V OUTPUT tPLH Figure 6. Driver Timing Test Circuit f = 1MHz, tR 3ns, tF 3ns 3V DI 0V 1.5V tPLH tPHL 1.5V 1/2 VO Figure 10. Receiver Propagation Delays Z VO Y 1/2 VO VDIFF = V (Y) - V (Z) VO VDIFF 0V -VO 90% 10% tR tSKEW = | tPLH - tPHL | tF 90% 10% RE 3V 1.5V 0V tZL(SHDN), tZL VCC RO 1.5V tLZ VOL + 0.5V 1.5V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH RO 0V tZH(SHDN), tZH tHZ 1.5V VOH - 0.5V Figure 7. Driver Propagation Delays OUTPUT UNDER TEST CL RL S1 VCC Figure 11. Receiver Enable and Disable Times S2 Figure 8. Enable/Disable Timing Test Load 10 ______________________________________________________________________________________ +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers Propagation Delay B ATE VID A R RECEIVER OUTPUT MAX3465-MAX3469 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 MAX3465-MAX3469 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 MAX3465-MAX3469 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 MAX3465-MAX3469 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. Chip Information TRANSISTOR COUNT: 610 PROCESS: BiCMOS Low-Power Shutdown Mode (Except MAX3467) Low-power shutdown mode is initiated by bringing SHDN high (MAX3465/MAX3466), 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 devices 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 devices are guaranteed to enter shutdown. Ordering Information (continued) PART MAX3466CSD MAX3466CPD MAX3466ESD MAX3466EPD MAX3467CSA MAX3467CPA MAX3467ESA MAX3467EPA MAX3468CSA MAX3468CPA MAX3468ESA MAX3468EPA MAX3469CSA MAX3469CPA MAX3469ESA MAX3469EPA 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 the Typical Operating Characteristics). The second, a thermal-shutdown circuit, forces the driver outputs into a high-impedance state if the die temperature exceeds +140C. ______________________________________________________________________________________ 11 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers MAX3465-MAX3469 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 MAX3468 MAX3469 (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 B A 120 120 R B 120 Y D Z DE RE R A RO DI B R D D R MAX3465 MAX3466 MAX3467 (FULL-DUPLEX) DI DE RE RO DI DE RE RO NOTE: RE AND DE ON MAX3465/MAX3466/MAX3467 ONLY. Figure 14. Typical Full-Duplex RS-485 Network Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE 14 SO 14 PDIP PACKAGE CODE -- -- DOCUMENT NO. 21-0041 21-0043 12 ______________________________________________________________________________________ +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers Revision History REVISION NUMBER 0 1 2 REVISION DATE 10/09 1/04 8/09 Initial release. Updated the description for the DE pin in the Pin Description table. Replaced TOC 11. DESCRIPTION PAGES CHANGED -- 6 5 MAX3465-MAX3469 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 ____________________ 13 (c) 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc. |
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