MAX485ED

Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 DESCRIPTION The MAX485 is a half-duplex transceiver that meets the specifications of RS-485 and RS-422. Its BiCMOS design allows low power operation without sacrificing performance. The MAX485 meets the requirements of the RS-485 and RS-422 protocols up to 5Mbps SOP-8 underload. The ESD tolerance is more than ±8kV for both Human Body Model and ±15kV for IEC61000-4-2 DIP-8 Air Discharge Method on this device. FEATURES • Single +5V Supply • Low Power BiCMOS • Driver/Receiver Enable for Multi-Drop Configurations • Half-Duplex Versions Available • Data rate: 5 Mbps • ESD Specifications TRUTH TABLE - ±15kV IEC61000-4-2 Air Discharge Transmission - ±8kV Human Body Model Inputs APPLICATIONS • Low Power RS-485 Systems • DTE-DCE Interface • Packet Switching • Local Area Networks • Data Concentration • Data Multiplexers • Integrated Services Digital Network (ISDN) R 7 B DE 3 6 A 4 Apr. 2019_R1.1 D DE DI A B X 1 1 1 0 X 1 0 0 1 0 0 X Z Z 1 0 X Z Z Receiver Outputs RE DE A-B RO 0 0 ≥ +0.2V 1 0 0 ≤ -0.2V 0 0 0 Open 1 1 0 X Z 8 VCC RE 2 DI RE Inputs PIN CONFIGRUATION AND LOGIC DIAGRAM RO 1 Outputs 5 GND 1 /10 HTC Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 ORDERING INFORMATION Package Oder No. Description Marking Compliance Status SOP-8 MAX485ED RS-485/RS-422 Transceivers MAX485E RoHS, Green Active DIP-8 MAX485EN RS-485/RS-422 Transceivers MAX485E RoHS, Green Contact us MAX 485 Package Type D N : SOP-8 : DIP-8 Ambient Temperature E : -40℃ ~ 85℃ Root Name Product Code Apr. 2019_R1.1 2 /10 HTC Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 ABSOLUTE MAXIMUM RATINGS Characteristic Symbol Supply Voltage Min VCC Max Unit 7 V Control Input Voltage VDE, VRE -0.3 VCC + 0.5 V Driver Input Voltage VDI -0.3 VCC + 0.5 V Driver Output Voltage A, B -15 15 V Receiver Input Voltage A, B -15 15 V Receiver Output Voltage VRO -0.3 VCC + 0.5 V TJ -40 125 °C TSTG -65 150 °C Symbol Min Max Unit Supply Voltage VCC 4.75 5.25 V Operating Ambient Temperature Ranges TA -40 85 °C Junction Temperature Storage Temperature Range RECOMMENDED OPERATING CONDITIONS Characteristic Apr. 2019_R1.1 3 /10 HTC Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 PIN CONFIGURATION 1 2 8 1 7 2 8 7 MAX485EN MAX485ED 3 6 3 6 4 5 4 5 SOP-8 DIP-8 PIN DESCRIPTION SOP-8 / DIP-8 PKG Pin No. Function Name 1 RO Receiver Output 2 RE* Receiver Output Enable Active Low 3 DE Driver Output Enable Active High 4 DI Driver Input 5 GND 6 A Non-inverting Driver Output and Receiver Input 7 B Inverting Driver Output and Receiver Input 8 VCC Apr. 2019_R1.1 Ground Power Supply: 4.75V to 5.25V 4 /10 HTC Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 ELECTRICAL CHARACTERISTICS Unless otherwise specified: VCC = 5V ± 5%, TA = TMIN to TMAX PARAMETER DRIVER DC Characteristics Differential Driver Output (no load) Differential Driver Output (with load) Change in Magnitude of Driver Differential Output Voltage for Complementary Output States Driver Common-Mode Output Voltage Change in Magnitude of Driver Common-Mode Output Voltage for Complementary Output States Input High Voltage Input Low Voltage Input Current Driver Short Circuit Current Driver Short-Circuit Current, VO = High Driver Short-Circuit Current, VO = Low DRIVER AC Characteristics Max. Transmission Rate Driver Input to Output Driver Output Skew to Output Driver Rise or Fall Time Driver Enable to Output High Driver Enable to Output Low Driver Disable Time from Low Driver Disable Time from High RECEIVER DC Characteristics Receiver Differential Threshold Voltage Receiver Input Hysteresis Receiver Output High Voltage Receiver Output Low Voltage Three-State (High Impedance) Output Current at Receiver Receiver Input Resistance Symbol MAX UNITS GND VCC V 2 1.5 VCC VCC V MIN TYP VOD1 RL = ∞, Figure 1 VOD2 RL = 50Ω (RS-422), Figure 1 RL = 27Ω (RS-485), Figure 1 ΔVOD RL = 27Ω or 50Ω, Figure 1 0.2 V VOC RL = 27Ω or 50Ω, Figure 1 3 V ΔVOC R = 27Ω or 50Ω, Figure 1 0.2 V 0.8 ±10 V V uA VIH VIL IIN1 DE, DI, RE* DE, DI, RE* DE, DI, RE* 2.0 IOSD1 -7V ≤ VO ≤ 12V ±250 mA IOSD2 -7V ≤ VO ≤ 12V ±250 mA 60 60 10 40 70 70 70 70 Mbps ns ns ns ns ns ns ns ns 0.2 V 0.4 mV V V ±1 uA fMAX tDPLH tDPHL tSKEW tr , tf tZH tZL tHZ tLZ VTH 5 Figure 4 & 6 CL=100pF S2 closed S1 closed S2 closed S1 closed -7V ≤ VCM ≤ 12V -0.2 VCM = 0V IO = -4mA, VID = +200mV IO = +4mA, VID = -200mV IOZR 0.4V ≤ VO ≤ 2.4V, RE* = 5V RIN -7V ≤ VCM ≤ 12V IIN2 Receiver Short-Circuit Current IOSR 30 30 5 15 40 40 40 40 Figure 3 & 5 RL = 54Ω, CL1 = CL2 = 100pF ΔVTH VOH VOL Input Current (A, B) Apr. 2019_R1.1 CONDITIONS DE = 0V VCC = 0V or 5.25V 0V ≤ VO ≤ VCC 5 /10 20 3.5 12 VIN = 12V VIN = -7V 7 kΩ 15 1.0 -0.8 95 mA mA HTC Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 RECEIVER AC Characteristics Receiver Input to Output | tPLH - tPHL | Differential Receiver Skew Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable Time from Low Receiver Disable Time from High Supply Current No-Load Supply Current Apr. 2019_R1.1 tPLH tPHL tSKD 20 20 Figure 2 & 7 S1, S2 open CL = 15pF 45 45 13 tZL tZH tLZ tHZ Figure 2 & 8 CL = 15pF S1 closed S2 closed S1 closed S2 closed 45 45 45 45 ICC RE = 0V or VCC DE=VCC DE=0V 900 600 6 /10 100 100 ns ns ns 70 70 70 70 ns ns ns Ns uA HTC Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 TEST CIRCUITS A VCC RO RL S1 Receiver Output VOD RL 1kΩ VOC S2 CL B Figure1. Figure 2. VCC CL1 DI D Output Under Test RL VO S1 500Ω CL CL2 DE Figure 3. S2 Figure 4. tSKEW = |tDPLH – tDPHL| 3V Driver Input 1.5V 1.5V 0V tDPLH tDPHL Z 1/2VO Driver Output 1/2VO VO Y VO Differential Output 90% 90% 0V VDIFF=V(Y) - V(Z) -VO 10% 10% tR tF Figure 5. Apr. 2019_R1.1 7 /10 HTC Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 3V 1.5V DE 1.5V 0V tLZ tZL Y, Z 2.3V A, B VOL + 0.5V VOL VOH Y, Z VOH – 0.5V 2.3V A, B 0V tZH tHZ Figure 6. VOH RO 1.5V 1.5V OUTPUT VOL tPLH tPHL VOD2+ A-B 0V 0V INPUT VOD2- Figure 7. 3V 1.5V RE* 1.5V 0V tLZ tZL VCC 1.5V VOL + 0.5V RO VIL VIH VOH – 0.5V 1.5V 0V tZH tHZ Figure 8. Apr. 2019_R1.1 8 /10 HTC Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 APPLICATION INFORMATION FUNCTIONAL DESCRIPTION The MAX485 is half-duplex differential transceiver that meets the requirements of RS-485 and RS-422. The RS-485 standard is ideal for multi-drop applications and for long-distance interfaces. RS-485 allows up to 32 drivers and 32 receivers to be connected to a data bus, making it an ideal choice for multi-drop applications. Since the cabling can be as long as 4,000 feet, RS-485 transceivers are equipped with a wide (-7V to +12V) common mode range to accommodate ground potential differences. Because RS-485 is a differential interface, data is virtually immune to noise in the transmission line. DRIVERS The driver outputs of the MAX485 are differential outputs meeting the RS-485 and RS-422 standards. The typical voltage output swing with no load will be 0 Volts to +5 Volts. With worst case loading of 54Ω across the differential outputs, the drivers can maintain greater than 1.5V voltage levels. The drivers of the MAX485 have an enable control line which is active HIGH. A logic HIGH on DE (pin 3) will enable the differential driver outputs. A logic LOW on the DE(pin 3) will tri-state the driver output. The transmitters of the MAX485 will operate up to at least 5Mbps. RECEIVERS The MAX485 receiver has differential inputs with an input sensitivity as low as ±200mV. Input impedance of the receivers is typically 15kΩ (12kΩ minimum). A wide common mode range of -7V to +12V allows for large ground potential differences between systems. The receivers of the MAX485 have a tri-state enable control pin. A logic LOW on RE* (pin 2) will enable the receiver, a logic HIGH on RE*(pin 2) will disable the receiver. The receiver for the MAX485 will operate up to at least 5Mbps. The receiver is equipped with the fail-safe feature. Fail-safe guarantees that the receiver output will be in a HIGH state when the input is left unconnected. Apr. 2019_R1.1 9 /10 HTC Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers MAX485 REVISION NOTICE The description in this datasheet can be revised without any notice to describe its electrical characteristics properly. Apr. 2019_R1.1 10 /10 HTC