Low power RS-485/RS-422 transceiver

www.DataSheet4U.com ST485 Low power RS-485/RS-422 transceiver General features I I I I I I I I I Low quiescent current: 300mA Designed for RS-485 interface application -7V to 12V common mode input voltage range Driver maintains high impedance in 3-state or with the power OFF 70mV tipycal input hysteresis 30ns propagation delay, 5ns skew Operate from a single 5V supply Current limiting and thermal shutdown for driver overload protection Allows up to 64 transceivers on the bus DIP-8 SO-8 Description The ST485 is al low power transceiver for RS-485 and RS-422 communication. Each part contains one driver and one receiver. This transceiver draw 300mA (typ.) of supply current when unloaded or fully loaded with disabled drivers. It operates from a single 5V supply. Driver is short-circuit current limited and is protected against excessive power dissipation by thermal shutdown circuitry that placed the driver outputs into a high-impedance state. The ST485 is designed for bi-directional data communications on multipoint bus transmission line (half-duplex applciations). The ST485 is available in three temperature range: commercial (0°C to 70°C), industrial (40°C to 850°C) and automotive (-55°C to 125°C) Order code Part number ST485CN ST485BN ST485XN ST485CD ST485BD ST485CDR ST485BDR ST485XDR Temperature range 0 to 70 °C -40 to 85 °C -55 to 125 °C 0 to 70 °C -40 to 85 °C 0 to 70 °C -40 to 85 °C -55 to 125 °C Package DIP-8 DIP-8 DIP-8 SO-8 (Tube) SO-8 (Tube) SO-8 (Tape & reel) SO-8 (Tape & reel) SO-8 (Tape & reel) Comments 50parts per tube / 40tube per box 50parts per tube / 40tube per box 50parts per tube / 40tube per box 100parts per tube / 20tube per box 100parts per tube / 20tube per box 2500 parts per reel 2500 parts per reel 2500 parts per reel March 2006 Rev 12 1/19 www.st.com 19 Contents ST485 Contents 1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 3 4 Truth tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.1 4.2 Driver switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Receiver switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5 6 7 Test circuit and typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2/19 ST485 Pin configuration 1 Pin configuration Figure 1. Pin configuration 1.1 Pin description Table 1. Pin description Symbol RO RE DE DI GND A B VCC Receiver Output Receiver Output Enable Driver Output Enable Driver Input Ground Non-inverting Receiver Input and Non-inverting Driver Output Inverting Receiver Input and Inverting Driver Output Supply Voltage Name and function Pin n° 1 2 3 4 5 6 7 8 3/19 Truth tables ST485 2 Truth tables Table 2. Truth table (driver) Inputs RE X X X DE H H L DI H L X B L H Z Outputs A H L Z Note: Table 3. X = Don’t care; Z = High impedance Truth table (receiver) Inputs RE L L L H DE L L L L ≥ ≤ Outputs A-B +0.2V -0.2V RO H L H Z INPUTS OPEN X Note: X = Don’t care; Z = High impedance 4/19 ST485 Maximum ratings 3 Table 4. Symbol VCC VI VDI VDO VRI VRO Maximum ratings Absolute maximum ratings Parameter Supply Voltage Control Input Voltage (RE, DE) Driver Input Voltage (DI) Driver Output Voltage (A, B) Receiver Input Voltage (A, B) Receiver Output Voltage (RO) Value 7 -0.5 to (VCC + 0.5) -0.5 to (VCC + 0.5) ± 14 ± 14 -0.5 to (VCC + 0.5) Unit V V V V V V Note: Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. V+ and V- can have a maximum magnitude of +7V, but their absolute addition can not exceed 13 V. 5/19 Electrical characteristics ST485 4 Electrical characteristics VCC = 5V ± 5%, TA = TMIN to TMAX , unless otherwise specified. Typical values are referred to TA = 25°C) Table 5. DC Electrical characteristics Value Symbol Parameter Test conditions (1) -40 to 85 °C Min Typ Max 5 1.5 5 5 -55 to 125 °C Min Max 5 1.4 5 5 Unit VOD1 VOD2 Differential Driver Output (No Load) Differential Driver Output RL = 27Ω (RS-485) (Figure 2.) (With Load) RL = 50Ω (RS-422) (Figure 2.) Change in Magnitude of Driver Differential Output RL = 27Ω or 50Ω (Figure 2.) 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 Input Current (A, B) Receiver Differential Threshold Voltage Receiver Input Hysteresis Receiver Output High Voltage Receiver Output Low Voltage 3-State (High Impedance) Output Current at Receiver Receiver Input Resistance RL = 27Ω or 50Ω (Figure 2.) V V V ∆VOD 0.2 0.2 V VOC 3 3 V ∆VOC RL = 27Ω or 50Ω (Figure 2.) 0.2 0.2 V VIH VIL IIN1 IIN2 RE, DE, DI RE, DE, DI RE, DE, DI VCM = 0V or 5.25VVDE = 0V VIN = 12V VIN = -7V VCM = -7 to 12V VCM = 0V IO = -4mAVID = 200mV IO = 4mAVID = -200mV 2.0 0.8 ±2 1 -0.8 -0.2 70 3.5 0.4 0.2 2.0 0.8 ±2 1 -0.8 -0.2 0.2 V V µA mA mA V mV VTH ∆VTH VOH VOL 3.4 0.55 V V IOZR VO = 0.4 to 2.4V ±1 ±1 µA RIN VCM = -7 to 12V 24 24 KW 6/19 ST485 Table 5. DC Electrical characteristics Electrical characteristics Value Symbol Parameter Test conditions (1) -40 to 85 °C Min ICC No Load Supply Current (2) -55 to 125 °C Min Max 900 500 35 35 7 250 250 95 Unit Typ 400 300 Max 900 500 250 250 95 VRE = 0V or V CC VDE = VCC VDE = 0V VO = -7 to 12V (3) VO = -7 to 12V (3) VO = 0V to V CC 35 35 7 µA µA mA mA mA IOSD1 IOSD2 IOSR Driver Short-Circuit Current, VO=High Driver Short-Circuit Current, VO=Low Receiver Short-Circuit Current 1. All currents into device pins are positive; all cuttents out of device pins are negative; all voltages are referenced to device ground unless specified. 2. Supply current specification is valid for loaded transmitters when VDE = 0V 3. Applies to peak current. See typical Operating Characteristics. 4.1 Driver switching characteristics VCC = 5V ± 5%, TA = TMIN to TMAX , unless otherwise specified. Typical values are referred to TA = 25°C Table 6. Driver switching characteristics Value Symbol Parameter Test conditions (1) -40 to 85 °C Min. Typ. 30 5 3 15 70 70 70 70 Max. 60 10 40 90 90 90 90 -55 to 125°C Min. Max. 70 10 3 45 90 90 90 90 Unit tPLH tPHL tSK tTLH tTHL tPZH tPZL tPLZ tPHZ Propagation Delay Input to Output Output Skew to Output Rise or Fall Time Output Enable Time Output Enable Time Output Disable Time Output Disable Time RDIFF = 54ΩCL1 = C L2 = 100pF (See Figure 4. and Figure 6.) RDIFF = 54ΩCL1 = C L2 = 100pF (See Figure 4. and Figure 6.) RDIFF = 54ΩCL1 = C L2 = 100pF (See Figure 4. and Figure 6.) CL = 100pFS2 = Closed (See Figure 5. and Figure 7.) CL = 100pFS1 = Closed (See Figure 5. and Figure 7.) CL = 15pFS1 = Closed (See Figure 5. and Figure 7.) CL = 15pFS2 = Closed (See Figure 5. and Figure 7.) 10 ns ns ns ns ns ns ns 1. All currents into device pins are positive; all cuttents out of device pins are negative; all voltages are referenced to device ground unless specified. 7/19 Electrical characteristics ST485 4.2 Receiver switching characteristics VCC = 5V ± 5%, TA = TMIN to TMAX , unless otherwise specified. Typical values are referred to TA = 25°C) Table 7. Receiver switching characteristics Value Symbol Parameter Test conditions (1) -40 to 85 °C Min. Typ. 130 13 20 20 20 20 2.5 50 50 50 50 Max. 210 -55 to 125°C Min. Max. 230 Unit tPLH tPHL tSKD tPZH tPZL tPLZ tPHZ fMAX Propagation Delay Input RDIFF = 54ΩCL1 = CL2 = 100pF to Output (See Figure 4. and Figure 8.) Differential Receiver Skew Output Enable Time Output Enable Time Output Disable Time Output Disable Time Maximum Data Rate RDIFF = 54ΩCL1 = CL2 = 100pF (See Figure 4. and Figure 8.) CRL = 15pFS1 = Closed (See Fig. 2 and Figure 9.) CRL = 15pFS2 = Closed (See Fig. 2 and Figure 9.) CRL = 15pFS1 = Closed (See Fig. 2 and Figure 9.) CRL = 15pFS2 = Closed (See Fig. 2 and Figure 9.) 20 ns ns 56 56 56 56 2.5 ns ns ns ns Mbps 1. All currents into device pins are positive; all cuttents out of device pins are negative; all voltages are referenced to device ground unless specified 8/19 ST485 Test circuit and typical characteristics 5 Figure 2. Test circuit and typical characteristics Driver DC test load Figure 3. Receiver timing test load Figure 4. Drive/receiver timing test circuit Figure 5. Driver timing test load 9/19 Test circuit and typical characteristics Figure 6. Driver propagation delay ST485 Figure 7. Driver enable and disable time 10/19 ST485 Figure 8. Receiver propagation delay Test circuit and typical characteristics Figure 9. Receiver Enable and Disable Time 11/19 Test circuit and typical characteristics Figure 10. Receiver output current vs. output low voltage Figure 11. ST485 Receiver output current vs. output high voltage Figure 12. Driver output current vs. output low Figure 13. Driver output current vs. output voltage high voltage Figure 14. Supply current vs. temperature Figure 15. Receiver high level output voltage vs. temperature 12/19 ST485 Figure 16. Receiver low level output voltage vs. temperature Test circuit and typical characteristics Figure 17. Differential driver output voltage vs. temperature 13/19 Package mechanical data ST485 6