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| ST491A Low power high speed RS-485/RS-422 transceiver Features Low supply current: 5mA max Designed for RS485 interface applications -7V to 12V common mode input voltage range 70mV typical input hysteresis Designed for 25Mbps operation Operate from a single 5V supply 4kV ESD protection Current limiting and thermal shutdown for driver overload protection DIP-14 Description The ST491A is a low power transceiver for RS485 and RS-422 communications. The device contains one driver and one receiver in full duplex configuration. The ST491A draws 5mA (typ.) of supply current when unloaded and operates from a single 5V 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. Order code Part number ST491ACN Temperature range 0 to 70 C Package DIP-14 Packaging 25parts per tube / 40tube per box May 2007 Rev 6 1/17 www.st.com 17 Contents ST491A 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2/17 ST491A Pin configuration 1 Figure 1. Pin configuration Pin connections Table 1. Pin description Symbol NC RO RE DE DI GND GND NC Y Z A B VCC VCC Not connected Receiver output. Receiver output enable Driver output enable Inverting driver input Ground Ground Not connected Non-inverting driver output Inverting driver output Inverting receiver input Non-inverting receiver input Supply voltage Supply voltage Name and function Pin n 1 2 3 4 5 6 7 8 9 10 11 12 13 14 3/17 Truth tables ST491A 2 Table 2. Truth tables Truth table (driver) Inputs DI L H X DE H H L Y L H Z Outputs Z H L Z Note: Table 3. X = Don't care; Z = High impedance Truth table (receiver) Inputs A-B RE L L L L H Outputs RO H ? L H Z -0.2V between -0.2V to 0.2V -0.2V OPEN X Note: ?=Irrelevant; X = Don't care; Z = High impedance 4/17 ST491A Maximum ratings 3 Table 4. Symbol VCC VDI VY, VZ VA, VB VRO ESD Maximum ratings Absolute maximum ratings Parameter Supply voltage Driver input voltage Driver output voltage Receiver input voltage Receiver output voltage Human body model Value 7 -0.5 to 7 -7.5 to 12.5 -7.5 to 12.5 -0.3 to (VCC + 0.3) 3.5 Unit V V V V V KV Note: Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. 5/17 Electrical characteristics ST491A 4 Table 5. Electrical characteristics Electrical characteristics (VCC = 4.5V to 5.5V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA=25C) Parameter No load supply current Input capacitance Driver output capacitance Output capacitance Min. Typ. 2 1.8 1.2 2.3 Max. 5 Unit mA pF pF pF Symbol ISUPPLY CIN CYZ COUT Table 6. Transmitter electrical characteristics (VCC = 4.5V to 5.5V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA=25C) Parameter Differential drive output (no load) Differential drive output (with load) Differential drive 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 Power off output current RL= 54 (RS-422) (Figure 1.) RL= 100 (RS-422) (Figure 1.) 1.5 2 2.6 3 Test conditions Min. Typ. Max. VCC 5 Unit V V V Symbol VOD1 VOD2 VOD3 VOD RL= 54 or 100 (Figure 1.) 0 0.2 V VOC VOC IOFF IOSD VIL VIH RL= 54 (Figure 1.) RL= 54 (Figure 1.) VCC = 0V, VO=-7V to 12V 1 0 3 0.2 100 V V A mA V V Driver short circuit output current VO=-7V to 12V Input logic threshold low Input logic threshold high 35 250 0.8 2 6/17 ST491A Electrical characteristics Table 7. Receiver electrical characteristics (VCC = 4.5V to 5.5V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA=25C) Parameter Input current (A, B) Receiver differential threshold voltage Receiver input hysteresis Receiver output high voltage Receiver output low voltage Receiver input resistance Test conditions Other input = 0V VCC = 0 or 5.25V VCM = -7V to 12V VCM = 0V IOUT = -8mA, VID = 200mV IOUT = 8mA, VID = -200mV VCM = -7V to 12V 12 3.5 VIN=12V VIN=-7V -0.2 70 4.7 0.3 24 0.5 Min. Typ. 0.5 -0.35 Max. 1 mA -0.8 0.2 V mV V V K Unit Symbol IIN VTH VTH VOH VOL RRIN Table 8. Driver switching characteristics (VCC = 4.5V to 5.5V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA=25C) 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 Jitter <5% RL= 54 CL1=CL2=50pF, (Figure 1.) , , RL= 54 CL1=CL2=50pF, (Figure 1.) , RL= 54 CL1=CL2=50pF, (Figure 1.) CL= 50pF, S1 Closed CL= 50pF, S2 Closed CL= 15pF, S2 Closed CL= 15pF, S1 Closed Test conditions Min. 25 Typ. 50 10 1 8 14 14 10 16 16 3 12 25 25 25 25 Max. Unit Mbps ns ns ns ns ns ns ns Symbol DR tPLH tPHL tSKEW tTLH tTHL tPZL tPZH tPHZ tPLZ 7/17 Electrical characteristics Table 9. ST491A Receiver switching characteristics (VCC = 4.5V to 5.5V, TA = -40 to 85C, unless otherwise specified. Typical values are referred to TA=25C) Parameter Propagation delay input to output |tPLH - tPHL| Receiver output skew Rise or fall time Output enable time Output enable time Output disable time Output disable time Test conditions CL = 15pF, (Figure 2., Figure 4.) CL = 15pF, (Figure 2., Figure 4.) CL = 15pF, (Figure 2., Figure 4.) CRL= 15pF, S1 Closed CRL= 15pF, S2 Closed CRL= 15pF, S2 Closed CRL= 15pF, S1 Closed Min. Typ. 19 1 6 6 7 6 6 12 12 12 12 Max. 30 3 Unit ns ns ns ns ns ns ns Symbol tPLH tPHL tSKD tTLH tTHL tPZL tPZH tPHZ tPLZ 8/17 ST491A Test circuit and typical characteristics 5 Figure 2. Test circuit and typical characteristics Driver DC test load Figure 3. Receiver timing test load 9/17 Test circuit and typical characteristics ST491A Figure 4. Driver/receiver timing test circuit Figure 5. Driver timing test load 10/17 ST491A Test circuit and typical characteristics Figure 6. Driver propagation delay Figure 7. Receiver propagation delay 11/17 Test circuit and typical characteristics ST491A Figure 8. Receiver output current vs. output low voltage (output low) Figure 9. Receiver output current vs. output high voltage (output high) Figure 10. Driver diff. output voltage vs Figure 11. Driver diff. output voltage vs common mode voltage (diff. output common mode voltage (diff. output low) high) Figure 12. Driver short circuit current vs line voltage (output high) Figure 13. Receiver high level output voltage vs. temperature 12/17 ST491A Test circuit and typical characteristics Figure 14. Receiver input current vs input voltage 13/17 Package mechanical data ST491A 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 14/17 ST491A Package mechanical data Plastic DIP-14 MECHANICAL DATA mm. DIM. MIN. a1 B b b1 D E e e3 F I L Z 1.27 3.3 2.54 0.050 8.5 2.54 15.24 7.1 5.1 0.130 0.100 0.51 1.39 0.5 0.25 20 0.335 0.100 0.600 0.280 0.201 1.65 TYP MAX. MIN. 0.020 0.055 0.020 0.010 0.787 0.065 TYP. MAX. inch P001A 15/17 Revision history ST491A 7 Table 10. Date Revision history Revision history Revision 3 4 5 6 Mistake on Figure 1. Mistake on Figure 1 and Table 1 (Pin 13). Order codes has been updated and new template. Order codes has been updated. Changes 10-May-2005 04-Jul-2005 28-Apr-2006 28-May-2007 16/17 ST491A 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 AUTHORIZE REPRESENTATIVE OF ST, ST PRODUCTS ARE NOT DESIGNED, 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. 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 17/17 |
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