19-3038; Rev 2; 8/09 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers 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 54Ω 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. Features ♦ Recommended for Profibus Applications ♦ 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 54Ω) ♦ Hot-Swap Versions ♦ 1µA 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 Ordering Information Applications High-Speed RS-485 Communications PART TEMP RANGE PIN-PACKAGE High-Speed RS-422 Communications MAX3465CSD Level Translators MAX3465CPD 0°C to +70°C Industrial-Control Local Area Networks MAX3465ESD -40°C to +85°C 14 SO Profibus Applications MAX3465EPD -40°C to +85°C 14 Plastic DIP 0°C to +70°C 14 SO 14 Plastic DIP Ordering Information continued at end of data sheet. Pin Configurations appear at end of data sheet. Selector Guide MAX3465 Full RECEIVER/ DRIVER ENABLE Yes MAX3466 Full Yes PART NUMBER HALF/FULL DUPLEX LOWPOWER SHUTDOWN Yes Yes Yes RECEIVER/ DRIVER PHASE SELECT Yes No Yes HOT SWAP INDEPENDENT SHDN PIN PIN COUNT Yes 14 Yes 14 MAX3467 Full No No No No No 8 MAX3468 Half Yes Yes Yes No No 8 MAX3469 Half Yes Yes No No No 8 ________________________________________________________________ Maxim Integrated Products 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. 1 MAX3465–MAX3469 General Description MAX3465–MAX3469 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers 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 = +70°C) 8-Pin SO (derate 5.88mW/°C above +70°C)................471mW 8-Pin DIP (derate 9.09mW/°C above +70°C) ...............727mW 14-Pin SO (derate 8.33mW/°C above +70°C)..............667mW 14-Pin DIP (derate 10mW/°C above +70°C) ................800mW Operating Temperature Range MAX346_C__ ......................................................0°C to +70°C MAX346_E__....................................................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.) (Note 1) PARAMETER Power-Supply Range SYMBOL CONDITIONS VCC MIN TYP 4.75 MAX UNITS 5.25 V VCC V DRIVER Differential Driver Output (No Load) VOD Figure 5, R = ∞ Differential Driver Output VOD Figure 5, R = 27Ω Change in Magnitude of Differential Output Voltage ΔVOD Figure 5, R = 50Ω or 27Ω (Note 2) Driver Common-Mode Output Voltage VOC Figure 5, R = 50Ω or 27Ω Change in Magnitude of Common-Mode Voltage ΔVOC Figure 5, R = 50Ω or 27Ω (Note 2) Input High Voltage VIH DE, DI, RE, SHDN Input Low Voltage VIL DE, DI, RE, SHDN VHYS DE, DI, RE, SHDN Output Leakage (Y and Z) Full Duplex IO DE = GND, VCC = GND or +5.25V Input Current IIN DI, RE, DE, SHDN Input Hysteresis 2.1 V 0.2 V 3 V 0.2 V 2.0 V 0.8 50 VIN = +12V VIN = -7V Pulldown Current RXP = TXP = VCC Driver Short-Circuit Output Current (Note 3) IOSD 0 ≤ VOUT ≤ +12V, output low Driver Short-Circuit Foldback Output Current (Note 3) IOSFD +125 -100 5 15 -250 (VCC - 1V) ≤ VOUT ≤ +12V, output low +25 -7V ≤ VOUT ≤ +1V, output high µA 30 µA -25 Thermal Shutdown Threshold µA ±1 +250 -7V ≤ VOUT ≤ VCC, output high V mV mA mA °C 140 RECEIVER Differential Input Capacitance Input Current (A and B) Full Duplex 2 CA, B IA, B Between A and B DE = GND, VCC = GND or +5.25V 8 VIN = +12V VIN = -7V pF +250 -200 _______________________________________________________________________________________ µA +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers (VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS -200 -125 -50 mV Receiver Differential Threshold Voltage VTH -7V ≤ VCM ≤ +12V Receiver Input Hysteresis ΔVTH VCM = 0 Receiver Output High Voltage VOH IO = -4mA, VA - VB = VTH Receiver Output Low Voltage VOL IO = 4mA, VB - VA = VTH 0.4 V Three-State Output Current at Receiver IOZR 0 ≤ VO ≤ VCC ±1 µA Receiver Input Resistance RIN -7V ≤ VCM ≤ +12V 48 Receiver Output Short-Circuit Current IOSR 0 ≤ VRO ≤ VCC ±7 ESD Protection 20 mV VCC - 1.5 V kΩ ±95 mA A, B, Y, and Z pins (MAX3467/MAX3468/MAX3469) ±6 No load, DI = VCC or DI = GND 2.5 4 mA 1 10 µA Figures 6 and 7, RDIFF = 54Ω, CL = 50pF 15 ns Figures 6 and 7, RDIFF = 54Ω, CL = 50pF 10 ns Figures 6 and 7, RDIFF = 54Ω, CL = 50pF, TXP = GND or open 2 ns kV SUPPLY CURRENT Normal Operation (Static Condition) IQ Supply Current in SHDN ISHDN DE = GND and RE = VCC, or SHDN = VCC SWITCHING CHARACTERISTICS Driver Propagation Delay tPLH tPHL Driver Differential Output Rise or Fall Time tR Driver Output Skew |tPLH - tPHL| tSKEW tF Driver Output Transition Skew Guaranteed by design Maximum Data Rate 1 30 40 ns Mbps Driver Enable to Output High tZH Figures 8 and 9, S2 closed, RL = 500Ω, CL = 50pF 30 ns Driver Enable to Output Low tZL Figures 8 and 9, S1 closed, RL = 500Ω, CL = 50pF 30 ns Driver Disable Time from Low tLZ Figures 8 and 9, S1 closed, RL = 500Ω, CL = 50pF 30 ns Driver Disable to Output High tHZ Figures 8 and 9, S2 closed, RL = 500Ω, CL = 50pF 30 ns Driver Enable Skew Time |tZL - tZH| RL = 500Ω, CL = 50pF, S1 closed (Figures 8 and 9), output low 5 ns Driver Disable Skew Time |tZL - tZH| RL = 500Ω, CL = 50pF, S2 closed (Figures 8 and 9), output high 5 ns Figure 10, CL = 15pF (Note 4) 20 ns Receiver Propagation Delay tPLH tPHL _______________________________________________________________________________________ 3 MAX3465–MAX3469 ELECTRICAL CHARACTERISTICS (continued) ELECTRICAL CHARACTERISTICS (continued) (VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS |tPLH tPHL| Receiver Output Skew MIN TYP MAX UNITS Figure 10, CL = 15pF, RXP = GND or open (Note 4) 2 ns Receiver Enable to Output Low tZL Figures 8 and 11, RL = 1kΩ, CL = 15pF, S1 closed (Note 4) 30 ns Receiver Enable to Output High tZH Figures 8 and 11, RL = 1kΩ, CL = 15pF, S2 closed (Note 4) 30 ns Receiver Disable Time from Low tLZ Figures 8 and 11, RL = 1kΩ, CL = 15pF, S1 closed (Note 4) 30 ns Receiver Disable Time from High tHZ Figures 8 and 11, RL = 1kΩ, CL = 15pF, S2 closed (Note 4) 30 ns Time to Shutdown tSHDN 800 ns tZH (SHDN) Figures 8 and 9, RL = 500Ω, CL = 50pF, S2 closed (Note 5) 4 µs Driver Enable from Shutdown to Output Low tZL (SHDN) Figures 8 and 9, RL = 500Ω, CL = 50pF, S1 closed (Note 5) 4 µs Receiver Enable from Shutdown to Output High tZH (SHDN) Figures 8 and 11, RL = 1kΩ, CL = 15pF, S2 closed (Notes 4, 5) 4 µs Receiver Enable from Shutdown to Output Low tZL (SHDN) Figures 8 and 11, RL = 1kΩ, CL = 15pF, S1 closed (Notes 4, 5) 4 µs Driver Enable from Shutdown to Output High (Note 5) 50 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: ΔVOD and ΔVOC 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 = +25°C, unless otherwise noted.) OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE 2.35 2.30 DE = GND 2.25 40 30 20 2.20 10 -40 -20 0 20 40 TEMPERATURE (°C) 60 80 25 20 15 10 5 0 0 2.10 30 OUTPUT CURRENT (mA) 2.40 50 OUTPUT CURRENT (mA) DE = VCC 35 MAX3465 toc02 2.45 2.15 4 60 MAX3465 toc01 2.50 OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE MAX3465 toc03 NO-LOAD SUPPLY CURRENT vs. TEMPERATURE NO-LOAD SUPPLY CURRENT (mA) MAX3465–MAX3469 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers 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 OUTPUT HIGH VOLTAGE (V) _______________________________________________________________________________________ 4 5 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE 200 150 100 50 0 -15 10 35 60 150 125 100 75 4.90 4.80 4.75 4.70 4.65 4.60 -40 -15 10 35 60 85 -40 -15 10 35 60 85 TEMPERATURE (°C) TEMPERATURE (°C) RECEIVER PROPAGATION DELAY vs. TEMPERATURE DRIVER PROPAGATION DELAY vs. TEMPERATURE DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE 12 10 RDIFF = 54Ω OUTPUT VOLTAGE (V) 10 8 10 35 60 3.0 2.5 6 2.0 4 -15 MAX3465 toc09 RDIFF = 54Ω PROPAGATION DELAY (ns) 14 3.5 MAX3465 toc08 12 MAX3465 toc07 16 85 -40 -15 10 35 60 -40 85 -15 10 35 60 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE OUTPUT CURRENT vs. DRIVER OUTPUT LOW VOLTAGE (TA = +25°C) OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGE 1 OUTPUT CURRENT (mA) 120 80 0 1 2 3 4 DIFFERENTIAL OUTPUT VOLTAGE (V) 5 -120 -80 -40 40 0.1 85 MAX3465 toc12 160 OUTPUT CURRENT (mA) 10 -160 MAX3465 toc11 200 MAX3465 toc10 100 0 IO = 4mA 4.85 TEMPERATURE (°C) 18 -40 MAX3465 toc06 175 85 20 PROPAGATION DELAY (ns) IO = -4mA 50 -40 OUTPUT CURRENT (mA) MAX3465 toc05 250 200 RECEIVER OUTPUT LOW VOLTAGE (mV) MAX3465 toc04 SHUTDOWN SUPPLY CURRENT (nA) 300 RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE RECEIVER OUTPUT HIGH VOLTAGE (mV) SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE 0 0 3 6 9 OUTPUT LOW VOLTAGE (V) 12 -7 -5 -3 -1 1 3 5 OUTPUT HIGH VOLTAGE (V) _______________________________________________________________________________________ 5 MAX3465–MAX3469 Typical Operating Characteristics (continued) (VCC = +5V, TA = +25°C, unless otherwise noted.) MAX3465–MAX3469 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers Typical Operating Characteristics (continued) (VCC = +5V, TA = +25°C, unless otherwise noted.) DRIVER AND RECEIVER PROPAGATION DELAYS EYE DIAGRAM ENABLE RESPONSE TIME MAX3465 toc13 MAX3465 toc15 MAX3465 toc14 DI 5V/div 5V/div DE Y, Z 2V/div Y, Z 1V/div Y, Z 1V/div RO 5V/div RDIFF = 54Ω RDIFF = 54Ω RDIFF = 54Ω DATA RATE = 20Mbps 10ns/div DATA RATE = 20Mbps 10ns/div 20ns/div Pin Description PIN FULL DUPLEX 6 HALF DUPLEX MAX3465/ MAX3466 MAX3467 MAX3468/ MAX3469 1 — — NAME SHDN FUNCTION Shutdown. Drive SHDN high to enter low-power shutdown mode. 2 2 1 RO Receiver Output. When RE is low and (A - B) ≥ -50mV, RO is high; if (A - B) ≤ -200mV, RO is low. 3 — 2 RE 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. 4 — 3 DE 5 3 4 DI 6, 7 4 5 GND 8 — — TXP 9 10 11 12 5 6 7 8 — — — — Y Z B A 13 — — RXP 14 — — 1 — — 8 7 6 VCC B A 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 15µA 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 15µA pulldown. Positive Supply: +4.75V ≤ VCC ≤ +5.25V. Bypass VCC to GND with a 0.1µF capacitor. Inverting Receiver Input and Inverting Driver Output Noninverting Receiver Input and Noninverting Driver Output _______________________________________________________________________________________ +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers MAX3465/MAX3466 MAX3467 TRANSMITTING TRANSMITTING INPUTS OUTPUTS INPUT OUTPUTS RE DE DI SHDN Z Y DI Z Y X 1 1 0 0 1 1 0 1 X 1 0 0 1 0 0 1 0 0 0 X 0 High-Z High-Z 1 0 X X Shutdown X X X 1 Shutdown RECEIVING OUTPUT A-B RO ≥ -0.05V 1 OUTPUT ≤ -0.2V 0 Open/Shorted 1 RECEIVING INPUTS INPUTS RE DE A-B SHDN RO 0 X ≥ -0.05V 0 1 0 X ≤ -0.2V 0 0 0 X Open/Shorted 0 1 1 1 X 0 High-Z 1 0 X X Shutdown X X X 1 Shutdown MAX3468/MAX3469 TRANSMITTING INPUTS OUTPUTS RE DE DI B A X 1 1 0 1 X 1 0 1 0 0 0 X High-Z High-Z 1 0 X Shutdown RECEIVING INPUTS OUTPUT RE DE A-B RO 0 X ≥ -0.05V 1 0 X ≤ -0.2V 0 0 X Open/Shorted 1 1 1 X High-Z 1 0 X Shutdown _______________________________________________________________________________________ 7 MAX3465–MAX3469 Function Tables MAX3465–MAX3469 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers Pin Configurations and Typical Operating Circuit VCC DE TOP VIEW 4 SHDN 1 VCC RE 0.1μF 14 14 VCC 13 RXP RO 2 RE 3 12 A DE 4 11 B R DI 5 9 DI 5 D GND 6 9 GND 7 8 Y TXP Y Rt 10 RO R Z A 12 10 Z D MAX3465 MAX3466 RO TXP RXP 2 R 8 Rt 11 D DI B 13 3 6, 7 GND DIP/SO RE DE GND Figure 1. MAX3465/MAX3466 Pin Configuration and Typical Full-Duplex Operating Circuit 0.1μF TOP VIEW VCC MAX3467 VCC 1 5 VCC 1 RO 2 DI 3 R 8 A DI D Y Rt 6 RO R Z 7 B 6 Z 5 Y A 8 D GND 4 3 RO 2 R Rt 7 D DI B DIP/SO 4 GND GND Figure 2. MAX3467 Pin Configuration and Typical Full-Duplex Operating Circuit TOP VIEW 0.1μF RO 1 R 8 VCC RO 1 RE 2 7 B RE 2 DE 3 6 A DE 3 5 GND DI 4 DI 4 D R VCC 8 7 B A 5 DI D RO Rt A GND DIP/SO NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH. Figure 3. MAX3468/MAX3469 Pin Configuration and Typical Full-Duplex Operating Circuit 8 R B Rt 6 D DE MAX3468 MAX3469 _______________________________________________________________________________________ RE +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers 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. 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. defined logic level. Leakage currents up to 10µA 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 15µs. After the initial power-up sequence, the pulldown circuit becomes transparent, resetting the hot-swap-tolerable input. 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 15µs timer turns on M2 and sets the SR latch, which also turns on M1. Transistors M2, a 2mA current sink, and M1, a 100µA current sink, pull DE to GND through a 5.6kΩ 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 15µs, 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 15μs 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 5.6kΩ DE (HOT SWAP) EN 100μA M1 2mA M2 Figure 4. Simplified Structure of the Driver Enable Pin (DE) _______________________________________________________________________________________ 9 MAX3465–MAX3469 Detailed Description MAX3465–MAX3469 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers 3V Y DE 1.5V 1.5V 0V R tLZ tZL(SHDN), tZL VOD Y, Z R 50% VOL VOC Z VOL + 0.5V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH Y, Z 50% VOH - 0.5V 0V tHZ tZH(SHDN), tZH Figure 5. Driver DC Test Load Figure 9. Driver Enable and Disable Times 3V DE DI Y VID RDIFF CL f = 1MHz, tR ≤ 3ns, tF ≤ 3ns Z VOH RO 1.5V 1V A -1V B 1.5V OUTPUT VOL tPHL tPLH INPUT Figure 6. Driver Timing Test Circuit Figure 10. Receiver Propagation Delays f = 1MHz, tR ≤ 3ns, tF ≤ 3ns 3V DI 1.5V 0V 1.5V tPLH tPHL 1/2 VO Z 3V VO 1.5V RE Y 1.5V 0V 1/2 VO VDIFF = V (Y) - V (Z) VO VDIFF 0V -VO tZL(SHDN), tZL 90% 90% 10% 10% tR VCC RO 1.5V RO 1.5V tLZ OUTPUT NORMALLY LOW VOL + 0.5V tF OUTPUT NORMALLY HIGH tSKEW = | tPLH - tPHL | RL OUTPUT UNDER TEST VOH - 0.5V 0V Figure 7. Driver Propagation Delays tZH(SHDN), tZH S1 VCC tHZ Figure 11. Receiver Enable and Disable Times CL S2 Figure 8. Enable/Disable Timing Test Load 10 ______________________________________________________________________________________ +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers B ATE R VID RECEIVER OUTPUT A Figure 12. Receiver Propagation Delay Test Circuit Applications Information 128 Transceivers on the Bus The standard RS-485 receiver input impedance is 12kΩ (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 (48kΩ), 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. 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 1µA 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. 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 +140°C. 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. Profibus Termination The MAX3465–MAX3469 are designed for driving Profibus termination networks. With a worst-case loading of two termination networks with 220Ω termination impedance and 390Ω pullups and pulldowns, the drivers can drive VA-B > 2.1V output. Chip Information TRANSISTOR COUNT: 610 PROCESS: BiCMOS Ordering Information (continued) PART TEMP RANGE PIN-PACKAGE MAX3466CSD 0°C to +70°C 14 SO MAX3466CPD 0°C to +70°C 14 Plastic DIP MAX3466ESD -40°C to +85°C 14 SO MAX3466EPD -40°C to +85°C 14 Plastic DIP MAX3467CSA 0°C to +70°C 8 SO MAX3467CPA 0°C to +70°C 8 Plastic DIP MAX3467ESA -40°C to +85°C 8 SO MAX3467EPA -40°C to +85°C 8 Plastic DIP MAX3468CSA 0°C to +70°C 8 SO MAX3468CPA 0°C to +70°C MAX3468ESA -40°C to +85°C 8 SO 8 Plastic DIP MAX3468EPA -40°C to +85°C 8 Plastic DIP MAX3469CSA 0°C to +70°C 8 SO MAX3469CPA 0°C to +70°C 8 Plastic DIP MAX3469ESA -40°C to +85°C 8 SO MAX3469EPA -40°C to +85°C 8 Plastic DIP ______________________________________________________________________________________ 11 MAX3465–MAX3469 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. MAX3465–MAX3469 +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers 120Ω 120Ω B DI B DE D D DE A B A B A DI A R RO R RO RE RE R R D MAX3468 MAX3469 (HALF-DUPLEX) D DI DE RO DI RE DE RO RE Figure 13. Typical Half-Duplex RS-485 Network A Y 120Ω 120Ω R RO D B RE DE Z Z DI DI 120Ω D DE RE B 120Ω R Y RO A Y Z B A B Y Z B R MAX3465 MAX3466 MAX3467 (FULL-DUPLEX) R D DI A D 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. 12 PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 14 SO — 21-0041 14 PDIP — 21-0043 ______________________________________________________________________________________ +5V, Fail-Safe, 40Mbps, Profibus RS-485/ RS-422 Transceivers REVISION NUMBER REVISION DATE 0 10/09 1 2 DESCRIPTION PAGES CHANGED Initial release. — 1/04 Updated the description for the DE pin in the Pin Description table. 6 8/09 Replaced TOC 11. 5 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 © 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc. MAX3465–MAX3469 Revision History