19-2217; Rev 1; 2/03 +5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers Features ♦ Recommended for Profibus Applications ♦ Guaranteed 20Mbps Data Rate ♦ 20ns Transmitter and 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 MAX3460CSD 0°C to +70°C 14 SO Level Translators MAX3460CPD 0°C to +70°C 14 Plastic DIP Industrial-Control Local Area Networks MAX3460ESD -40°C to +85°C 14 SO Profibus Applications MAX3460EPD -40°C to +85°C 14 Plastic DIP Ordering Information continued at end of data sheet. Pin Configurations appear at end of data sheet. Selector Guide MAX3460 Full RECEIVER/ DRIVER ENABLE Yes Yes RECEIVER/ DRIVER PHASE SELECT Yes Yes 14 MAX3461 Full Yes Yes No Yes Yes 14 MAX3462 Full No No No No No 8 MAX3463 Half Yes Yes Yes No No 8 MAX3464 Half Yes Yes No No No 8 PART NUMBER HALF/FULL DUPLEX LOWPOWER SHUTDOWN Yes HOT SWAP INDEPENDENT SHDN PIN PIN COUNT ________________________________________________________________ Maxim Integrated Products 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. 1 MAX3460–MAX3464 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 54Ω 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. MAX3460–MAX3464 +5V, Fail-Safe, 20Mbps, 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 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 ∆VOD Figure 5, R = 50Ω or 27Ω (Note 2) 0.2 V Driver Common-Mode Output Voltage VOC Figure 5, R = 50Ω or 27Ω 3 V Change in Magnitude of Common-Mode Voltage ∆VOC Figure 5, R = 50Ω or 27Ω (Note 2) 0.2 V Input High Voltage VIH DE, DI, RE, SHDN 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 Low Voltage Input Hysteresis Pulldown Current VCC 2.1 2.0 0.8 VIN = +12V RXP = TXP = VCC Driver Short-Circuit Output Current (Note 3) IOSD Driver Short-Circuit Foldback Output Current (Note 3) IOSFD V 50 VIN = -7V -100 15 0 ≤ VOUT ≤ 12V, output low -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 +125 5 V V mA mA 140 °C 8 pF RECEIVER 2 Differential Input Capacitance CA, B Input Current (A and B) Full Duplex IA, B DE = GND, VCC = GND or 5.25V Receiver Differential Threshold Voltage VTH -7V ≤ VCM ≤ 12V VIN = +12V VIN = -7V 250 -200 -200 -125 _______________________________________________________________________________________ -50 µA mV +5V, Fail-Safe, 20Mbps, 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 Receiver Input Hysteresis ∆VTH V A + VB = 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 20 mV VCC - 1.5 V kΩ ±95 mA 2.5 4 mA 1 10 µA Figures 6 and 7, RDIFF = 54Ω, CL = 50pF 20 ns Figures 6 and 7, RDIFF = 54Ω, CL = 50pF 20 ns Figures 6 and 7, RDIFF = 54Ω, CL = 50pF, TXP = GND or floating 2 ns SUPPLY CURRENT Normal Operation (static condition) Supply Current in SHDN IQ ISHDN No load, DI = VCC or DI = GND 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 Maximum Data Rate 20 Mbps Driver Enable to Output High tZH Figures 8 and 9, S2 closed, RL = 500Ω, CL = 50pF Driver Enable to Output Low tZL Figures 8 and 9, S1 closed, RL = 500Ω, CL = 50pF 100 ns Driver Disable Time from Low tLZ Figures 8 and 9, S1 closed, RL = 500Ω, CL = 50pF 100 ns Driver Disable Time from High tHZ Figures 8 and 9, S2 closed, RL = 500Ω, CL = 50pF 100 ns Figure 10, CL = 15pF (Note 4) 20 ns Figure 10, CL = 15pF, RXP = GND or floating (Note 4) 2 ns Receiver Propagation Delay Receiver Output Skew |tPLH - tPHL| tPLH tPHL tSKEW 100 ns Receiver Enable to Output Low tZL Figures 8 and 11, RL = 1kΩ, CL = 15pF, S1 closed (Note 4) 100 ns Receiver Enable to Output High tZH Figures 8 and 11, RL = 1kΩ, CL = 15pF, S2 closed (Note 4) 100 ns Receiver Disable Time from Low tLZ Figures 8 and 11, RL = 1kΩ, CL = 15pF, S1 closed (Note 4) 100 ns Receiver Disable Time from High tHZ Figures 8 and 11, RL = 1kΩ, CL = 15pF, S2 closed (Note 4) 100 ns _______________________________________________________________________________________ 3 MAX3460–MAX3464 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 Time to Shutdown CONDITIONS tSHDN MIN (Note 5) TYP 50 MAX UNITS 800 ns Driver Enable from Shutdown to Output High 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 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 = +25°C, unless otherwise noted.) NO LOAD SUPPLY CURRENT vs. TEMPERATURE 2.25 2.20 DE = GND 2.15 2.10 40 30 20 10 2.05 2.00 -20 0 20 40 TEMPERATURE (°C) 60 80 MAX3460-64 toc03 30 25 20 15 10 5 0 0 -40 4 50 35 OUTPUT CURRENT (mA) 2.30 MAX3460-64 toc02 DE = VCC 60 OUTPUT CURRENT (mA) MAX3460-64 toc01 2.35 OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE 2.40 NO LOAD SUPPLY CURRENT (mA) MAX3460–MAX3464 +5V, Fail-Safe, 20Mbps, 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, 20Mbps, Profibus RS-485/ RS-422 Transceivers 30 20 10 0 120 100 -15 10 35 60 4.80 4.75 4.70 4.60 -40 -15 10 35 60 -40 85 -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 8 7 -15 10 35 60 4.0 MAX3460-64 toc08 RDIFF = 54Ω CL = 50pF 10 OUTPUT VOLTAGE (V) PROPAGATION DELAY (ns) MAX3460-64 toc07 9 12 8 RDIFF = 54Ω 3.5 3.0 2.5 6 2.0 4 85 MAX3460-64 toc09 TEMPERATURE (°C) 10 -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 OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGE 1 120 80 40 0 0.1 1 2 3 4 DIFFERENTIAL OUTPUT VOLTAGE (V) 5 85 MAX3460-64 toc12 MAX3460-64 toc11 160 -160 OUTPUT CURRENT (mA) 10 200 OUTPUT CURRENT (mA) MAX3460-64 toc10 100 0 IO = -4mA 4.85 4.65 85 11 -40 MAX3460-64 toc06 140 4.90 80 -40 PROPAGATION DELAY (ns) IO = 4mA OUTPUT HIGH VOLTAGE (V) 40 MAX3460-64 toc05 MAX3460-64 toc04 SHUTDOWN SUPPLY CURRENT (nA) 50 OUTPUT CURRENT (mA) RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE RECEIVER OUTPUT LOW VOLTAGE (mV) SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE -120 -80 -40 0 0 3 6 9 OUTPUT LOW VOLTAGE (V) 12 -7 -5 -3 -1 1 3 5 OUTPUT HIGH VOLTAGE (V) _______________________________________________________________________________________ 5 MAX3460–MAX3464 Typical Operating Characteristics (continued) (VCC = +5V, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +5V, TA = +25°C, unless otherwise noted.) DRIVER AND RECEIVER PROPAGATION DELAYS ENABLE RESPONSE TIME EYE DIAGRAM MAX3460-64 toc14 MAX3460-64 toc13 MAX3460-64 toc15 MAX3460–MAX3464 +5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers 5V/div DE DI 0 5V/div Y, Z 2V/div 0 1V/div Y, Z 0 RO 0 0 5V/div 10ns/div 20ns/div 10ns/div Pin Description PIN MAX3460/ MAX3461 MAX3462 FULL DUPLEX 1 6 — MAX3463/ MAX3464 NAME FUNCTION HALF DUPLEX — SHDN 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. 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 VCC — — — — 7 6 B A 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 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, 20Mbps, Profibus RS-485/ RS-422 Transceivers MAX3460/MAX3461 MAX3462 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 RECEIVING INPUTS 1 ≤ -0.2V 0 Open/Shorted 1 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 1 RO ≥ -0.05V DE X OUTPUT A–B OUTPUT RE X INPUTS Shutdown MAX3463/MAX3464 TRANSMITTING INPUTS OUTPUTS RE DE DI B A X 1 1 0 1 X 1 0 1 0 0 0 X High-Z 1 0 X High-Z 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 MAX3460–MAX3464 Function Tables MAX3460–MAX3464 +5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers Pin Configurations and Typical Operating Circuit VCC DE TOP VIEW 4 SHDN 1 VCC RE 2 RE 3 12 A DE 4 11 B 9 13 RXP R DI 5 DI 5 D GND 7 8 12 RO Y TXP Rt 10 10 Z 9 Y RO R Z D GND 6 0.1µF 14 14 VCC RO MAX3460 MAX3461 TXP RXP 2 R 8 A Rt 11 DI D B 13 3 6, 7 GND DIP/SO RE DE GND Figure 1. MAX3460/MAX3461 Pin Configuration and Typical Full-Duplex Operating Circuit 0.1µF TOP VIEW VCC MAX3462 VCC 1 5 VCC 1 R 8 A DI D Y Rt 6 RO R Z RO 2 7 B DI 3 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. MAX3462 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 R DI D RO B Rt 6 D DE MAX3463 MAX3464 GND DIP/SO Rt A RE NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH. Figure 3. MAX3463/MAX3464 Pin Configuration and Typical Full-Duplex Operating Circuit 8 _______________________________________________________________________________________ +5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers 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. 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. level. Leakage currents up to 10µA 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 15µs. 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 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 complimentary circuit employing two PMOS devices pulling RE 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 output drivers are high impedance and are unable to drive the DE input of the MAX3460/MAX3463 to a defined logic 5.6kΩ DE (HOT SWAP) EN 100µA M1 2mA M2 Figure 4. Simplified Structure of the Driver Enable Pin (DE) _______________________________________________________________________________________ 9 MAX3460–MAX3464 Detailed Description MAX3460–MAX3464 +5V, Fail-Safe, 20Mbps, Profibus RS-485/ Y R OUTPUT UNDER TEST VOD VCC S1 RL CL R S2 VOC Z Figure 8. Enable/Disable Timing Test Load Figure 5. Driver DC Test Load 3V DE 1.5V 1.5V 0 tLZ tZL(SHDN), tZL Y, Z 2.3V VOL OUTPUT NORMALLY HIGH Y, Z 2.3V 3V VOH - 0.5V 0 DE DI VOL + 0.5V OUTPUT NORMALLY LOW tHZ tZH(SHDN), tZH Y VID RDIFF CL Figure 9. Driver Enable and Disable Times Z ƒ = 1MHz, tR ≤ 3ns, tF ≤ 3ns VOH RO 1.5V 1V A -1V B 1.5V OUTPUT VOL Figure 6. Driver Timing Test Circuit tPHL tPLH INPUT Figure 10. Receiver Propagation Delays ƒ = 1MHz, tR ≤ 3ns, tF ≤ 3ns 3V 3V DI 1.5V 0 1.5V tPLH 1.5V RE 1.5V 0 tPHL 1/2 VO tZL(SHDN), tZL Z VO VCC RO 1.5V RO 1.5V Y tLZ OUTPUT NORMALLY LOW VOL + 0.5V 1/2 VO OUTPUT NORMALLY HIGH VDIFF = V (Y) - V (Z) VO VDIFF 0 -VO 90% 90% 10% 10% tR tF VOH - 0.5V 0 tZH(SHDN), tZH tHZ tSKEW = | tPLH - tPHL | Figure 7. Driver Propagation Delays 10 Figure 11. Receiver Enable and Disable Times ______________________________________________________________________________________ +5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers B ATE R VID RECEIVER OUTPUT A Figure 12. Receiver Propagation Delay Test Circuit 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. Typical Applications 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 MAX3460–MAX3464 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 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 1µA 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. 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 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. Profibus Termination The MAX3460–MAX3464 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 0°C to +70°C 14 SO MAX3461CPD 0°C to +70°C 14 Plastic DIP MAX3461ESD -40°C to +85°C 14 SO MAX3461EPD -40°C to +85°C 14 Plastic DIP MAX3462CSA 0°C to +70°C 8 SO MAX3462CPA 0°C to +70°C 8 Plastic DIP MAX3462ESA -40°C to +85°C 8 SO MAX3462EPA -40°C to +85°C 8 Plastic DIP MAX3463CSA 0°C to +70°C 8 SO MAX3463CPA 0°C to +70°C 8 Plastic DIP MAX3463ESA -40°C to +85°C 8 SO MAX3463EPA -40°C to +85°C 8 Plastic DIP MAX3464CSA 0°C to +70°C 8 SO MAX3464CPA 0°C to +70°C 8 Plastic DIP MAX3464ESA -40°C to +85°C 8 SO MAX3464EPA -40°C to +85°C 8 Plastic DIP MAX3461CSD ______________________________________________________________________________________ 11 MAX3460–MAX3464 high-impedance state if the die temperature exceeds +140°C. MAX3460–MAX3464 +5V, Fail-Safe, 20Mbps, 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 D MAX3463 MAX3464 (HALF-DUPLEX) 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 120Ω D DE RE B 120Ω R Y A Y Z B A B Y Z R D DI R D DE RE RO DI DE RE MAX3460 MAX3461 MAX3462 (FULL-DUPLEX) RO NOTE: RE AND DE ON MAX3460/MAX3461/MAX3462 ONLY Figure 14. Typical Full-Duplex RS-485 Network 12 DI ______________________________________________________________________________________ RO +5V, Fail-Safe, 20Mbps, Profibus RS-485/ RS-422 Transceivers N E H INCHES MILLIMETERS 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 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 SOICN .EPS DIM A A1 B C e E H L 1.27 VARIATIONS: 1 INCHES TOP VIEW DIM D D D MIN 0.189 0.337 0.386 MAX 0.197 0.344 0.394 MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.00 N MS012 8 AA 14 AB 16 AC D A B e C 0 -8 A1 L FRONT VIEW SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, .150" SOIC APPROVAL DOCUMENT CONTROL NO. 21-0041 REV. B 1 1 ______________________________________________________________________________________ 13 MAX3460–MAX3464 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.) 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.) PDIPN.EPS MAX3460–MAX3464 +5V, Fail-Safe, 20Mbps, Profibus RS-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 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 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.