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ST485AB Very high speed low power RS-485/RS-422 transceiver Features Low supply current: 5 mA max High data rate > 30 Mbps Designed for RS 485 interface applications -7 to 12 common mode input voltage range Driver maintains high impedance in 3-state or with the power off 70mV typical input hysteresis Operate from single 5 supply 4 kV ESD protection Current limiting and thermal shutdown for driver overload protection Latch-up free up to 500 mA The ST485A is designed for bi-directional data communications or multipoint bus transmission lines. DIP-8 SO-8 Description The ST485A is a low power, high speed transceiver for RS-485 and RS-422 communications. The device contains one driver and one receiver in half duplex configuration. The ST485A draws 3 mA (typ.) of supply current when unloaded or fully loaded with disabled drivers. It operates from a single 5 V supply. 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 receiver input has a fail-safe feature that guarantees a logic high output if both inputs are open circuit. Table 1. Device summary Temperature range -40 to 85 C -40 to 85 C Package DIP-8 SO-8 (Tape & reel) Rev. 3 Packaging 50parts per tube / 40tube per box 2500 parts per reel 1/19 www.st.com 19 Order code ST485ABN ST485ABDR August 2007 Contents ST485AB Contents 1 2 3 4 5 6 7 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Truth tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Test circuit and typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2/19 ST485AB Pin configuration 1 Figure 1. Pin configuration Pin configuration Table 2. Pin n 1 2 Pin description Symbol RO RE Name and function Receiver output. If A>B by 200 mV, RO will be high; if A3 DE 4 5 6 7 8 DI GND A B VCC 3/19 Truth tables ST485AB 2 Table 3. Truth tables Truth table (driver) Inputs RE X X L DE H H L DI H L X B L H Z Outputs A H L Z Mode A Normal Normal Normal Note: Table 4. X = Don't care; Z = High impedance Truth table (receiver) Inputs RE L L L DE L L L Outputs Mode A-B -0.2 V V RO H L H Normal Normal Normal -0.2 Inputs open Note: X = Don't care; Z = High impedance 4/19 ST485AB Maximum ratings 3 Table 5. 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 -0.3 to 7 -0.3 to 7 -7.5 to 12.5 -7.5 to 12.5 -0.3 to (VCC + 0.3) 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. 5/19 Electrical characteristics ST485AB 4 Table 6. Symbol Electrical characteristics DC electrical characteristics (VCC = 4.5 V to 5.5 V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA = 25C, VCC = 5 V) (Note: 1) Parameter Test conditions No load, VRE=0 V or VCC VDE = VCC VDE = 0 V Min. Typ. 2.3 2.6 10 10 Max. 5 5 Unit mA mA pF pF ISUPPLY VCC Power supply current CI/O CAB Input/output capacitance Driver output capacity Table 7. Symbol VIL VIH IIN1 IIN2 Logic input electrical characteristics (VCC = 4.5 V to 5.5 V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA = 25C, VCC = 5 V) (Note: 1) Parameter Input logic threshold low Input logic threshold high Logic input current Input current (A, B) DE, DI, RE DE, DI, RE DE, DI, RE VDE=0 V, VCC= 0 or 5.25 V VIN=12 V VIN=-7 V 2 2.0 1 -0.8 Test conditions Min. Typ. Max. 0.8 Unit V V A mA mA Table 8. Symbol VOD1 VOD2 Transmitter electrical characteristics (VCC = 4.5 V to 5.5 V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA = 25C, VCC = 5 V) (Note: 1) Parameter Differential driver output (No load) Differential driver output (with load) Change in magnitude of driver differential output voltage for complementary output states (Note: 1) Driver common mode output voltage Change in magnitude of driver common mode output voltage (Note: 1) Driver short circuit output current RL= 54 (RS-422) VCM= -7 V to 12 V RL= 27 or 50 1.5 2.7 Test conditions Min. Typ. Max. 5 5 Unit V V VOD 0 0.2 V VOC VOC IOSD RL= 27 or 50 RL= 54 or 100 VO= -7 V to 12 V 1 3 V 0 0.2 250 V mA 6/19 ST485AB Electrical characteristics Table 9. Symbol VTH VTH VOH VOL IOZR RRIN IOSR Receiver electrical characteristics (VCC = 4.5 V to 5.5 V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA = 25C, VCC = 5 V) (Note: 1) Parameter 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 Receiver Short-Circuit Current Test conditions VCM = -7 V to 12 V VCM = 0 V IOUT = -4 mA, VID = 200 mV IOUT = 4 mA, VID = -200 mV VO = 0.4 V to 2.4 V VCM = -7 V to 12 V VO = 0 V to VCC 12 7 24 95 3.5 Min. -0.2 70 4.7 0.2 0.4 1 Typ. Max. 0.2 Unit V mV V V A K mA Table 10. Symbol DR tPLH tPHL tSKEW tTLH tTHL tPZL tPZH tPHZ tPLZ tSK(EN) tSK(DS) Driver switching characteristics (VCC = 4.5 V to 5.5 V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA = 25C, VCC = 5 V) (See Note: 1, Note 3) Parameter Maximum data rate Propagation delay input to output Differential output delay skew Rise or fall differential time Output enable time Output enable time Output disable time Output disable time Synchronous driver operation a-b at enable Synchronous driver operation A-B at disable 4 Test conditions Jitter < 5% , RL= 54 CL1=CL2=50 pF, (Figure 8.) , RL= 54 CL1=CL2=50 pF, (Figure 6.) RL= 54 CL1=CL2=50 pF, , (Figure 6.) CL= 50 pF, S1 Closed CL= 50 pF, S2 Closed CL= 15 pF, S2 Closed CL= 15 pF, S1 Closed Min. 30 Typ. 50 18 0.5 8 30 2 12 30 30 30 30 2 6 Max. Unit Mbps ns ns ns ns ns ns ns ns ns 7/19 Electrical characteristics ST485AB Table 11. Symbol tPLH tPHL tRPDS tPZL tPZH tPHZ tPLZ Driver switching characteristics (VCC = 4.5V to 5.5V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA = 25C, VCC = 5V) (See Note: 1, Note 3) Parameter Propagation Delay Test conditions CL = 15 pF Min. Typ. 18 0.5 7 7 7 7 Max. 30 2 12 12 12 12 Unit ns ns ns ns ns ns |tPLH - tPHL| Propagation delay skew CL = 15 pF Output enable time Output enable time Output disable time Output disable time CRL = 15 pF, S1 Closed CRL = 15 pF, S2 Closed CRL = 15 pF, S2 Closed CRL = 15 pF, S1 Closed Note: 1 2 3 All currents into device pins are positive; all currents out of device pins are negative; all voltages are referenced to device ground unless specified. Applies to peak current. See typical Operating Characteristics. tr=tf 6 ms. 8/19 ST485AB 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. Driver/receiver timing test circuit 9/19 Test circuit and typical characteristics ST485AB Figure 5. Driver timing test load Figure 6. Driver timing test load 10/19 ST485AB Test circuit and typical characteristics Figure 7. Driver enable and disable time Figure 8. Receiver propagation delay 11/19 Test circuit and typical characteristics ST485AB Figure 9. Receiver enable and disable time Figure 10. Receiver output current vs. output voltage (output low) Figure 11. Receiver output current vs. output voltage (output high) 12/19 ST485AB Test circuit and typical characteristics Figure 12. Driver diff. output voltage vs Figure 13. Driver diff. output voltage vs common mode voltage (diff. output common mode voltage (diff. output low) low) Figure 14. Driver short circuit current vs line voltage (output high) Figure 15. Driver short circuit current vs. line voltage (output low) Figure 16. Receiver input current vs input voltage 13/19 Package mechanical data ST485AB 6 Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK(R) 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 14/19 ST485AB Package mechanical data Plastic DIP-8 mechanical data mm. Dim. Min. A a1 B B1 b b1 D E e e3 e4 F I L Z 0.44 3.3 1.6 0.017 8.8 2.54 7.62 7.62 7.1 4.8 0.130 0.063 0.38 0.7 1.39 0.91 0.5 0.5 9.8 0.346 0.100 0.300 0.300 0.280 0.189 0.015 1.65 1.04 Typ. 3.3 0.028 0.055 0.036 0.020 0.020 0.386 0.065 0.041 Max. Min. Typ. 0.130 Max. inch. P001F 15/19 Package mechanical data ST485AB SO-8 mechanical data Dim. A A1 A2 B C D E e H h L k ddd 0.1 5.80 0.25 0.40 mm. Min. 1.35 0.10 1.10 0.33 0.19 4.80 3.80 1.27 6.20 0.50 1.27 8 (max.) 0.04 0.228 0.010 0.016 Typ. Max. 1.75 0.25 1.65 0.51 0.25 5.00 4.00 Min. 0.053 0.04 0.043 0.013 0.007 0.189 0.150 0.050 0.244 0.020 0.050 inch. Typ. Max. 0.069 0.010 0.065 0.020 0.010 0.197 0.157 0016023/C 16/19 ST485AB Package mechanical data Tape & reel SO-8 mechanical data mm. Dim. Min. A C D N T Ao Bo Ko Po P 8.1 5.5 2.1 3.9 7.9 12.8 20.2 60 22.4 8.5 5.9 2.3 4.1 8.1 0.319 0.216 0.082 0.153 0.311 Typ. Max. 330 13.2 0.504 0.795 2.362 0.882 0.335 0.232 0.090 0.161 0.319 Min. Typ. Max. 12.992 0.519 inch. 17/19 Revision history ST485AB 7 Table 12. Date Revision history Revision history Revision 2 3 Changes Order codes updated and new template. Added Table 1. in cover page. 28-Mar-2006 24-Aug-2007 18/19 ST485AB 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. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such third party products or services or any intellectual property contained therein. UNLESS OTHERWISE SET FORTH IN ST'S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE, ST PRODUCTS ARE NOT RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY, DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER'S OWN RISK. Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any liability of ST. ST and the ST logo are trademarks or registered trademarks of ST in various countries. Information in this document supersedes and replaces all information previously supplied. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. (c) 2007 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com 19/19 |
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