ST485EB ST485EC - ST485EX ±15 kV ESD protected, low power RS-485/RS-422 transceiver Features ■ Low quiescent current: 300 µA ■ Designed for RS-485 interface application ■ -7 V to 12 V common mode input voltage range ■ Driver maintains high impedance in 3-state or with the power OFF ■ 70 mV typical input hysteresis ■ 30 ns propagation delay, 5 ns skew ■ Operates from a single 5 V supply ■ Current limiting and thermal shutdown for driver overload protection ■ ESD protection: – ±15 kV (H.B.M.) – ±8 kV (IEC-1000-4-2 contact discharge) ■ SO-8 Driver is short-circuit current limited and is protected against excessive power dissipation by thermal shutdown circuitry that place the driver outputs into a high-impedance state. The ST485E is designed for bi-directional data communications on multipoint bus transmission lines (half-duplex applications). Allows up to 256 transceivers on the bus Description The ST485E is a low power transceiver for RS485 and RS-422 communication. Each driver output and receiver input is protected against ±15 kV electrostatic discharge (H.B.M.) (ESD) shocks, without latch-up. These parts contain one driver and one receiver in half duplex configuration. This transceiver draws 300 µA (typ.) of supply current when unloaded or fully loaded with disabled drivers. It operates from a single 5 V supply. Table 1. Device summary Order codes Temperature range Package Packaging ST485EBD -40 to 85 °C SO-8 (Tube) 100parts per tube / 20tube per box ST485ECDR 0 to 70 °C SO-8 (Tape and reel) 2500 parts per reel ST485EBDR -40 to 85 °C SO-8 (Tape and reel) 2500 parts per reel ST485EXDR -55 to 125 °C SO-8 (Tape and reel) 2500 parts per reel February 2008 Rev 13 1/18 www.st.com 18 Contents ST485EB - ST485EC - ST485EX Contents 1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Truth tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Test circuit and typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2/18 ST485EB - ST485EC - ST485EX 1 Pin configuration Figure 1. Pin connections (top view) Table 2. Pin description Pin configuration Pin n° Symbol Name and function 1 RO Receiver output 2 RE Receiver output enable 3 DE Driver output enable 4 DI Driver input 5 GND 6 A Non-inverting receiver input and non-inverting driver output 7 B Inverting receiver input and inverting driver output 8 VCC Ground Supply voltage 3/18 Truth tables ST485EB - ST485EC - ST485EX 2 Truth tables Table 3. Truth table (driver) Inputs Outputs RE DE DI B A X H H L H X H L H L X L X Z Z Note: X = Don’t care; Z = High impedance Table 4. Truth table (receiver) Inputs Note: 4/18 Outputs RE DE A-B L L L L ≤-0.2V L L L Inputs open H H L X Z ≥ X = Don’t care; Z = High impedance +0.2V RO H ST485EB - ST485EC - ST485EX Maximum ratings 3 Maximum ratings Table 5. Absolute maximum ratings Symbol VCC Parameter Supply voltage Value Unit 7 V VI Control input voltage (RE, DE) -0.5 to (VCC + 0.5) V VDI Driver input voltage (DI) -0.5 to (VCC + 0.5) V VDO Driver output voltage (A, B) ± 14 V VRI Receiver input voltage (A, B) ± 14 V VRO Receiver output voltage (RO) -0.5 to (VCC + 0.5) V Note: Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these is not implied. V+ and V- can have a maximum magnitude of +7 V, but their absolute addition exceed 13 V. 5/18 Electrical characteristics ST485EB - ST485EC - ST485EX 4 Electrical characteristics Table 6. ESD performance: transmitter outputs, receiver inputs Symbol Parameter Test conditions Min. Typ. Max. Unit ESD ESD protection voltage Human body model ±15 kV ESD ESD protection voltage IEC-1000-4-2 ±8 kV Table 7. DC electrical characteristics (VCC = 5 V ± 5 %, TA = TMIN to TMAX, unless otherwise specified. Typical values are referred to TA = 25 °C) Test conditions (1) Symbol Parameter VOD1 Differential driver output (no load) VOD2 Differential driver output (with load) RL = 27 Ω (RS-485) (Figure 2) RL = 50 Ω (RS-422) (Figure 2.) ΔVOD Change in magnitude of driver differential output voltage for complementary output states RL = 27 Ω or 50 Ω (Figure 2) VOC Driver common-mode output RL = 27 Ω or 50 Ω (Figure 2) voltage ΔVOC Change in magnitude of driver common-mode output voltage for complementary output states RL = 27 Ω or 50 Ω (Figure 2) VIH Input high voltage RE, DE, DI VIL Input low voltage RE, DE, DI 0.8 V IIN1 Input current RE, DE, DI ±2 µA IIN2 Input current (A, B) VCM = 0 V or 5.25 V, VDE = 0 V VIN = 12 V VIN = -7 V 1 -0.8 mA mA VTH Receiver differential threshold voltage VCM = -7 to 12 V 0.2 V ΔVTH Receiver input hysteresis VCM = 0 V VOH Receiver output high voltage IO = -4 mA, VID = 200 mV VOL Receiver output low voltage IO = 4 mA, VID = -200 mV 0.4 V IOZR 3-State (high impedance) output current at receiver VO = 0.4 to 2.4 V ±1 µA RIN Receiver input resistance VCM = -7 to 12 V ICC No load supply current (2) VRE = 0V or VCC VDE = VCC VDE = 0 V IOSD1 Driver short-circuit current, VO=High VO = -7 to 12 V (3) 6/18 Min. Typ. 1.5 Max. Unit 5 V 5 5 V V 0.2 V 3 V 0.2 V 2.0 V -0.2 70 mV 3.5 V 96 kΩ 400 300 35 900 500 µA µA 250 mA ST485EB - ST485EC - ST485EX Table 7. Symbol Electrical characteristics DC electrical characteristics (continued) (VCC = 5 V ± 5 %, TA = TMIN to TMAX, unless otherwise specified. Typical values are referred to TA = 25 °C) Parameter Test conditions (1) IOSD2 Driver short-circuit current, VO=Low IOSR Receiver short-circuit current VO = 0 V to VCC VO = -7 to 12 V (3) Min. Typ. Max. Unit 35 250 mA 7 95 mA 1. All currents into device pins are positive; all 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 = 0 V 3. Applies to peak current. See typical Operating Characteristics. Table 8. Symbol Driver switching characteristics (VCC = 5 V ± 5 %, TA = TMIN to TMAX, unless otherwise specified. Typical values are referred to TA = 25 °C) Parameter Test conditions (1) Min. Typ. Max. Unit tPLH tPHL Propagation delay input to RDIFF = 54 Ω, CL1 = CL2 = 100 pF output (See Figure 4 and Figure 6) 25 45 ns tSK Output skew to output RDIFF = 54 Ω, CL1 = CL2 = 100 pF (See Figure 4 and Figure 6) 2 5 ns tTLH tTHL Rise or fall time RDIFF = 54 Ω, CL1 = CL2 = 100 pF (See Figure 4 and Figure 6) 15 40 ns tPZH Output enable time CL = 100 pF, S2 = Closed (See Figure 5 and Figure 7) 35 50 ns tPZL Output enable time CL = 100 pF, S1 = Closed (See Figure 5 and Figure 7) 25 40 ns tPLZ Output disable time CL = 15 pF, S1 = Closed (See Figure 5 and Figure 7) 25 40 ns tPHZ Output disable time CL = 15 pF, S2 = Closed (See Figure 5 and Figure 7) 35 50 ns 1. All currents into device pins are positive; all out of device pins are negative; all voltages are referenced to device ground unless specified. 7/18 Electrical characteristics Table 9. Symbol ST485EB - ST485EC - ST485EX Receiver switching characteristics (VCC = 5 V ± 5%, TA = TMIN to TMAX, unless otherwise specified. Typical values are referred to TA = 25 °C) Parameter Test conditions (1) Min. Typ. Max. Unit tPLH tPHL Propagation delay input to output RDIFF = 54 Ω, CL1 = CL2 = 100 pF (See Figure 4 and Figure 8) 110 130 ns tSKD Differential receiver skew RDIFF = 54 Ω, CL1 = CL2 = 100 pF (See Figure 4 and Figure 8) 5 10 ns tPZH Output enable time CRL = 15 pF, S1 = Closed (See Figure 2 and Figure 9) 11 35 ns tPZL Output enable time CRL = 15 pF, S2 = Closed (See Figure 2 and Figure 9) 13 35 ns tPLZ Output disable time CRL = 15 pF, S1 = Closed (See Figure 2 and Figure 9) 13 35 ns tPHZ Output disable time CRL = 15 pF, S2 = Closed (See Figure 2 and Figure 9) 11 35 ns fMAX Maximum data rate 5 Mbps 1. All currents into device pins are positive; all out of device pins are negative; all voltages are referenced to device ground unless specified 8/18 ST485EB - ST485EC - ST485EX Test circuit and typical characteristics 5 Test circuit and typical characteristics Figure 2. Driver DC test load Figure 3. Receiver timing test load Figure 4. Drive/receiver timing test circuit Figure 5. Driver timing test load 9/18 Test circuit and typical characteristics Figure 6. Driver propagation delay Figure 7. Driver enable and disable time 10/18 ST485EB - ST485EC - ST485EX ST485EB - ST485EC - ST485EX Figure 8. Receiver propagation delay Figure 9. Receiver enable and disable time Test circuit and typical characteristics 11/18 Test circuit and typical characteristics Figure 10. Receiver output current vs output low voltage ST485EB - ST485EC - ST485EX Figure 11. 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 12/18 Figure 15. Receiver high level output voltage vs temperature ST485EB - ST485EC - ST485EX Figure 16. Receiver low level output voltage vs temperature Test circuit and typical characteristics Figure 17. Differential driver output voltage vs temperature 13/18 Package mechanical data 6 ST485EB - ST485EC - ST485EX Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com 14/18 ST485EB - ST485EC - ST485EX Package mechanical data SO-8 mechanical data Dim. mm. Min. Typ. inch. Max. Min. Typ. Max. A 1.35 1.75 0.053 0.069 A1 0.10 0.25 0.04 0.010 A2 1.10 1.65 0.043 0.065 B 0.33 0.51 0.013 0.020 C 0.19 0.25 0.007 0.010 D 4.80 5.00 0.189 0.197 E 3.80 4.00 0.150 0.157 e 1.27 0.050 H 5.80 6.20 0.228 0.244 h 0.25 0.50 0.010 0.020 L 0.40 1.27 0.016 0.050 k ddd 8° (max.) 0.1 0.04 0016023/C 15/18 Package mechanical data ST485EB - ST485EC - ST485EX Tape & reel SO-8 mechanical data mm. inch. Dim. Min. A Max. Min. 330 13.2 Typ. Max. 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 16/18 Typ. 0.504 22.4 0.519 0.882 Ao 8.1 8.5 0.319 0.335 Bo 5.5 5.9 0.216 0.232 Ko 2.1 2.3 0.082 0.090 Po 3.9 4.1 0.153 0.161 P 7.9 8.1 0.311 0.319 ST485EB - ST485EC - ST485EX 7 Revision history Table 10. Document revision history Revision history Date Revision Changes 21-Mar-2006 9 Order codes has been updated and new template. 05-Jun-2006 10 Change value row 10 on the features and RIN in Table 7. 29-Jan-2007 11 Typo mistake on page 1. 29-Aug-2007 12 Change value RIN min. on Table 7. 07-Feb-2008 13 Modified: Table 1 on page 1. 17/18 ST485EB - ST485EC - ST485EX Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. 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